core/num/
uint_macros.rs

1macro_rules! uint_impl {
2    (
3        Self = $SelfT:ty,
4        ActualT = $ActualT:ident,
5        SignedT = $SignedT:ident,
6
7        // These are all for use *only* in doc comments.
8        // As such, they're all passed as literals -- passing them as a string
9        // literal is fine if they need to be multiple code tokens.
10        // In non-comments, use the associated constants rather than these.
11        BITS = $BITS:literal,
12        BITS_MINUS_ONE = $BITS_MINUS_ONE:literal,
13        MAX = $MaxV:literal,
14        rot = $rot:literal,
15        rot_op = $rot_op:literal,
16        rot_result = $rot_result:literal,
17        fsh_op = $fsh_op:literal,
18        fshl_result = $fshl_result:literal,
19        fshr_result = $fshr_result:literal,
20        swap_op = $swap_op:literal,
21        swapped = $swapped:literal,
22        reversed = $reversed:literal,
23        le_bytes = $le_bytes:literal,
24        be_bytes = $be_bytes:literal,
25        to_xe_bytes_doc = $to_xe_bytes_doc:expr,
26        from_xe_bytes_doc = $from_xe_bytes_doc:expr,
27        bound_condition = $bound_condition:literal,
28    ) => {
29        /// The smallest value that can be represented by this integer type.
30        ///
31        /// # Examples
32        ///
33        /// ```
34        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")]
35        /// ```
36        #[stable(feature = "assoc_int_consts", since = "1.43.0")]
37        pub const MIN: Self = 0;
38
39        /// The largest value that can be represented by this integer type
40        #[doc = concat!("(2<sup>", $BITS, "</sup> &minus; 1", $bound_condition, ").")]
41        ///
42        /// # Examples
43        ///
44        /// ```
45        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")]
46        /// ```
47        #[stable(feature = "assoc_int_consts", since = "1.43.0")]
48        pub const MAX: Self = !0;
49
50        /// The size of this integer type in bits.
51        ///
52        /// # Examples
53        ///
54        /// ```
55        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
56        /// ```
57        #[stable(feature = "int_bits_const", since = "1.53.0")]
58        pub const BITS: u32 = Self::MAX.count_ones();
59
60        /// Returns the number of ones in the binary representation of `self`.
61        ///
62        /// # Examples
63        ///
64        /// ```
65        #[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
66        /// assert_eq!(n.count_ones(), 3);
67        ///
68        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
69        #[doc = concat!("assert_eq!(max.count_ones(), ", stringify!($BITS), ");")]
70        ///
71        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
72        /// assert_eq!(zero.count_ones(), 0);
73        /// ```
74        #[stable(feature = "rust1", since = "1.0.0")]
75        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
76        #[doc(alias = "popcount")]
77        #[doc(alias = "popcnt")]
78        #[must_use = "this returns the result of the operation, \
79                      without modifying the original"]
80        #[inline(always)]
81        pub const fn count_ones(self) -> u32 {
82            return intrinsics::ctpop(self);
83        }
84
85        /// Returns the number of zeros in the binary representation of `self`.
86        ///
87        /// # Examples
88        ///
89        /// ```
90        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
91        #[doc = concat!("assert_eq!(zero.count_zeros(), ", stringify!($BITS), ");")]
92        ///
93        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
94        /// assert_eq!(max.count_zeros(), 0);
95        /// ```
96        #[stable(feature = "rust1", since = "1.0.0")]
97        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
98        #[must_use = "this returns the result of the operation, \
99                      without modifying the original"]
100        #[inline(always)]
101        pub const fn count_zeros(self) -> u32 {
102            (!self).count_ones()
103        }
104
105        /// Returns the number of leading zeros in the binary representation of `self`.
106        ///
107        /// Depending on what you're doing with the value, you might also be interested in the
108        /// [`ilog2`] function which returns a consistent number, even if the type widens.
109        ///
110        /// # Examples
111        ///
112        /// ```
113        #[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
114        /// assert_eq!(n.leading_zeros(), 2);
115        ///
116        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
117        #[doc = concat!("assert_eq!(zero.leading_zeros(), ", stringify!($BITS), ");")]
118        ///
119        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
120        /// assert_eq!(max.leading_zeros(), 0);
121        /// ```
122        #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
123        #[stable(feature = "rust1", since = "1.0.0")]
124        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
125        #[must_use = "this returns the result of the operation, \
126                      without modifying the original"]
127        #[inline(always)]
128        pub const fn leading_zeros(self) -> u32 {
129            return intrinsics::ctlz(self as $ActualT);
130        }
131
132        /// Returns the number of trailing zeros in the binary representation
133        /// of `self`.
134        ///
135        /// # Examples
136        ///
137        /// ```
138        #[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
139        /// assert_eq!(n.trailing_zeros(), 3);
140        ///
141        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
142        #[doc = concat!("assert_eq!(zero.trailing_zeros(), ", stringify!($BITS), ");")]
143        ///
144        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
145        #[doc = concat!("assert_eq!(max.trailing_zeros(), 0);")]
146        /// ```
147        #[stable(feature = "rust1", since = "1.0.0")]
148        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
149        #[must_use = "this returns the result of the operation, \
150                      without modifying the original"]
151        #[inline(always)]
152        pub const fn trailing_zeros(self) -> u32 {
153            return intrinsics::cttz(self);
154        }
155
156        /// Returns the number of leading ones in the binary representation of `self`.
157        ///
158        /// # Examples
159        ///
160        /// ```
161        #[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
162        /// assert_eq!(n.leading_ones(), 2);
163        ///
164        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
165        /// assert_eq!(zero.leading_ones(), 0);
166        ///
167        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
168        #[doc = concat!("assert_eq!(max.leading_ones(), ", stringify!($BITS), ");")]
169        /// ```
170        #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
171        #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
172        #[must_use = "this returns the result of the operation, \
173                      without modifying the original"]
174        #[inline(always)]
175        pub const fn leading_ones(self) -> u32 {
176            (!self).leading_zeros()
177        }
178
179        /// Returns the number of trailing ones in the binary representation
180        /// of `self`.
181        ///
182        /// # Examples
183        ///
184        /// ```
185        #[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
186        /// assert_eq!(n.trailing_ones(), 3);
187        ///
188        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
189        /// assert_eq!(zero.trailing_ones(), 0);
190        ///
191        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
192        #[doc = concat!("assert_eq!(max.trailing_ones(), ", stringify!($BITS), ");")]
193        /// ```
194        #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
195        #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
196        #[must_use = "this returns the result of the operation, \
197                      without modifying the original"]
198        #[inline(always)]
199        pub const fn trailing_ones(self) -> u32 {
200            (!self).trailing_zeros()
201        }
202
203        /// Returns the minimum number of bits required to represent `self`.
204        ///
205        /// This method returns zero if `self` is zero.
206        ///
207        /// # Examples
208        ///
209        /// ```
210        /// #![feature(uint_bit_width)]
211        ///
212        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")]
213        #[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")]
214        #[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")]
215        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")]
216        /// ```
217        #[unstable(feature = "uint_bit_width", issue = "142326")]
218        #[must_use = "this returns the result of the operation, \
219                      without modifying the original"]
220        #[inline(always)]
221        pub const fn bit_width(self) -> u32 {
222            Self::BITS - self.leading_zeros()
223        }
224
225        /// Returns `self` with only the most significant bit set, or `0` if
226        /// the input is `0`.
227        ///
228        /// # Examples
229        ///
230        /// ```
231        /// #![feature(isolate_most_least_significant_one)]
232        ///
233        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
234        ///
235        /// assert_eq!(n.isolate_highest_one(), 0b_01000000);
236        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
237        /// ```
238        #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
239        #[must_use = "this returns the result of the operation, \
240                      without modifying the original"]
241        #[inline(always)]
242        pub const fn isolate_highest_one(self) -> Self {
243            self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
244        }
245
246        /// Returns `self` with only the least significant bit set, or `0` if
247        /// the input is `0`.
248        ///
249        /// # Examples
250        ///
251        /// ```
252        /// #![feature(isolate_most_least_significant_one)]
253        ///
254        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
255        ///
256        /// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
257        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
258        /// ```
259        #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
260        #[must_use = "this returns the result of the operation, \
261                      without modifying the original"]
262        #[inline(always)]
263        pub const fn isolate_lowest_one(self) -> Self {
264            self & self.wrapping_neg()
265        }
266
267        /// Returns the index of the highest bit set to one in `self`, or `None`
268        /// if `self` is `0`.
269        ///
270        /// # Examples
271        ///
272        /// ```
273        /// #![feature(int_lowest_highest_one)]
274        ///
275        #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".highest_one(), None);")]
276        #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".highest_one(), Some(0));")]
277        #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".highest_one(), Some(4));")]
278        #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".highest_one(), Some(4));")]
279        /// ```
280        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
281        #[must_use = "this returns the result of the operation, \
282                      without modifying the original"]
283        #[inline(always)]
284        pub const fn highest_one(self) -> Option<u32> {
285            match NonZero::new(self) {
286                Some(v) => Some(v.highest_one()),
287                None => None,
288            }
289        }
290
291        /// Returns the index of the lowest bit set to one in `self`, or `None`
292        /// if `self` is `0`.
293        ///
294        /// # Examples
295        ///
296        /// ```
297        /// #![feature(int_lowest_highest_one)]
298        ///
299        #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".lowest_one(), None);")]
300        #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
301        #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".lowest_one(), Some(4));")]
302        #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".lowest_one(), Some(0));")]
303        /// ```
304        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
305        #[must_use = "this returns the result of the operation, \
306                      without modifying the original"]
307        #[inline(always)]
308        pub const fn lowest_one(self) -> Option<u32> {
309            match NonZero::new(self) {
310                Some(v) => Some(v.lowest_one()),
311                None => None,
312            }
313        }
314
315        /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
316        ///
317        /// This produces the same result as an `as` cast, but ensures that the bit-width remains
318        /// the same.
319        ///
320        /// # Examples
321        ///
322        /// ```
323        #[doc = concat!("let n = ", stringify!($SelfT), "::MAX;")]
324        ///
325        #[doc = concat!("assert_eq!(n.cast_signed(), -1", stringify!($SignedT), ");")]
326        /// ```
327        #[stable(feature = "integer_sign_cast", since = "1.87.0")]
328        #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
329        #[must_use = "this returns the result of the operation, \
330                      without modifying the original"]
331        #[inline(always)]
332        pub const fn cast_signed(self) -> $SignedT {
333            self as $SignedT
334        }
335
336        /// Shifts the bits to the left by a specified amount, `n`,
337        /// wrapping the truncated bits to the end of the resulting integer.
338        ///
339        /// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
340        /// particular, a rotation by the number of bits in `self` returns the input value
341        /// unchanged.
342        ///
343        /// Please note this isn't the same operation as the `<<` shifting operator!
344        ///
345        /// # Examples
346        ///
347        /// ```
348        #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
349        #[doc = concat!("let m = ", $rot_result, ";")]
350        ///
351        #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
352        #[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
353        /// ```
354        #[stable(feature = "rust1", since = "1.0.0")]
355        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
356        #[must_use = "this returns the result of the operation, \
357                      without modifying the original"]
358        #[inline(always)]
359        #[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
360        pub const fn rotate_left(self, n: u32) -> Self {
361            return intrinsics::rotate_left(self, n);
362        }
363
364        /// Shifts the bits to the right by a specified amount, `n`,
365        /// wrapping the truncated bits to the beginning of the resulting
366        /// integer.
367        ///
368        /// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
369        /// particular, a rotation by the number of bits in `self` returns the input value
370        /// unchanged.
371        ///
372        /// Please note this isn't the same operation as the `>>` shifting operator!
373        ///
374        /// # Examples
375        ///
376        /// ```
377        #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
378        #[doc = concat!("let m = ", $rot_op, ";")]
379        ///
380        #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
381        #[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
382        /// ```
383        #[stable(feature = "rust1", since = "1.0.0")]
384        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
385        #[must_use = "this returns the result of the operation, \
386                      without modifying the original"]
387        #[inline(always)]
388        #[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
389        pub const fn rotate_right(self, n: u32) -> Self {
390            return intrinsics::rotate_right(self, n);
391        }
392
393        /// Performs a left funnel shift (concatenates `self` with `rhs`, with `self`
394        /// making up the most significant half, then shifts the combined value left
395        /// by `n`, and most significant half is extracted to produce the result).
396        ///
397        /// Please note this isn't the same operation as the `<<` shifting operator or
398        /// [`rotate_left`](Self::rotate_left), although `a.funnel_shl(a, n)` is *equivalent*
399        /// to `a.rotate_left(n)`.
400        ///
401        /// # Panics
402        ///
403        /// If `n` is greater than or equal to the number of bits in `self`
404        ///
405        /// # Examples
406        ///
407        /// Basic usage:
408        ///
409        /// ```
410        /// #![feature(funnel_shifts)]
411        #[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
412        #[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
413        #[doc = concat!("let m = ", $fshl_result, ";")]
414        ///
415        #[doc = concat!("assert_eq!(a.funnel_shl(b, ", $rot, "), m);")]
416        /// ```
417        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
418        #[unstable(feature = "funnel_shifts", issue = "145686")]
419        #[must_use = "this returns the result of the operation, \
420                      without modifying the original"]
421        #[inline(always)]
422        pub const fn funnel_shl(self, rhs: Self, n: u32) -> Self {
423            assert!(n < Self::BITS, "attempt to funnel shift left with overflow");
424            // SAFETY: just checked that `shift` is in-range
425            unsafe { intrinsics::unchecked_funnel_shl(self, rhs, n) }
426        }
427
428        /// Performs a right funnel shift (concatenates `self` and `rhs`, with `self`
429        /// making up the most significant half, then shifts the combined value right
430        /// by `n`, and least significant half is extracted to produce the result).
431        ///
432        /// Please note this isn't the same operation as the `>>` shifting operator or
433        /// [`rotate_right`](Self::rotate_right), although `a.funnel_shr(a, n)` is *equivalent*
434        /// to `a.rotate_right(n)`.
435        ///
436        /// # Panics
437        ///
438        /// If `n` is greater than or equal to the number of bits in `self`
439        ///
440        /// # Examples
441        ///
442        /// Basic usage:
443        ///
444        /// ```
445        /// #![feature(funnel_shifts)]
446        #[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
447        #[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
448        #[doc = concat!("let m = ", $fshr_result, ";")]
449        ///
450        #[doc = concat!("assert_eq!(a.funnel_shr(b, ", $rot, "), m);")]
451        /// ```
452        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
453        #[unstable(feature = "funnel_shifts", issue = "145686")]
454        #[must_use = "this returns the result of the operation, \
455                      without modifying the original"]
456        #[inline(always)]
457        pub const fn funnel_shr(self, rhs: Self, n: u32) -> Self {
458            assert!(n < Self::BITS, "attempt to funnel shift right with overflow");
459            // SAFETY: just checked that `shift` is in-range
460            unsafe { intrinsics::unchecked_funnel_shr(self, rhs, n) }
461        }
462
463        /// Reverses the byte order of the integer.
464        ///
465        /// # Examples
466        ///
467        /// ```
468        #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
469        /// let m = n.swap_bytes();
470        ///
471        #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
472        /// ```
473        #[stable(feature = "rust1", since = "1.0.0")]
474        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
475        #[must_use = "this returns the result of the operation, \
476                      without modifying the original"]
477        #[inline(always)]
478        pub const fn swap_bytes(self) -> Self {
479            intrinsics::bswap(self as $ActualT) as Self
480        }
481
482        /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
483        ///                 second least-significant bit becomes second most-significant bit, etc.
484        ///
485        /// # Examples
486        ///
487        /// ```
488        #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
489        /// let m = n.reverse_bits();
490        ///
491        #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
492        #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
493        /// ```
494        #[stable(feature = "reverse_bits", since = "1.37.0")]
495        #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
496        #[must_use = "this returns the result of the operation, \
497                      without modifying the original"]
498        #[inline(always)]
499        pub const fn reverse_bits(self) -> Self {
500            intrinsics::bitreverse(self as $ActualT) as Self
501        }
502
503        /// Converts an integer from big endian to the target's endianness.
504        ///
505        /// On big endian this is a no-op. On little endian the bytes are
506        /// swapped.
507        ///
508        /// # Examples
509        ///
510        /// ```
511        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
512        ///
513        /// if cfg!(target_endian = "big") {
514        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
515        /// } else {
516        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
517        /// }
518        /// ```
519        #[stable(feature = "rust1", since = "1.0.0")]
520        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
521        #[must_use]
522        #[inline(always)]
523        pub const fn from_be(x: Self) -> Self {
524            #[cfg(target_endian = "big")]
525            {
526                x
527            }
528            #[cfg(not(target_endian = "big"))]
529            {
530                x.swap_bytes()
531            }
532        }
533
534        /// Converts an integer from little endian to the target's endianness.
535        ///
536        /// On little endian this is a no-op. On big endian the bytes are
537        /// swapped.
538        ///
539        /// # Examples
540        ///
541        /// ```
542        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
543        ///
544        /// if cfg!(target_endian = "little") {
545        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
546        /// } else {
547        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
548        /// }
549        /// ```
550        #[stable(feature = "rust1", since = "1.0.0")]
551        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
552        #[must_use]
553        #[inline(always)]
554        pub const fn from_le(x: Self) -> Self {
555            #[cfg(target_endian = "little")]
556            {
557                x
558            }
559            #[cfg(not(target_endian = "little"))]
560            {
561                x.swap_bytes()
562            }
563        }
564
565        /// Converts `self` to big endian from the target's endianness.
566        ///
567        /// On big endian this is a no-op. On little endian the bytes are
568        /// swapped.
569        ///
570        /// # Examples
571        ///
572        /// ```
573        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
574        ///
575        /// if cfg!(target_endian = "big") {
576        ///     assert_eq!(n.to_be(), n)
577        /// } else {
578        ///     assert_eq!(n.to_be(), n.swap_bytes())
579        /// }
580        /// ```
581        #[stable(feature = "rust1", since = "1.0.0")]
582        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
583        #[must_use = "this returns the result of the operation, \
584                      without modifying the original"]
585        #[inline(always)]
586        pub const fn to_be(self) -> Self { // or not to be?
587            #[cfg(target_endian = "big")]
588            {
589                self
590            }
591            #[cfg(not(target_endian = "big"))]
592            {
593                self.swap_bytes()
594            }
595        }
596
597        /// Converts `self` to little endian from the target's endianness.
598        ///
599        /// On little endian this is a no-op. On big endian the bytes are
600        /// swapped.
601        ///
602        /// # Examples
603        ///
604        /// ```
605        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
606        ///
607        /// if cfg!(target_endian = "little") {
608        ///     assert_eq!(n.to_le(), n)
609        /// } else {
610        ///     assert_eq!(n.to_le(), n.swap_bytes())
611        /// }
612        /// ```
613        #[stable(feature = "rust1", since = "1.0.0")]
614        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
615        #[must_use = "this returns the result of the operation, \
616                      without modifying the original"]
617        #[inline(always)]
618        pub const fn to_le(self) -> Self {
619            #[cfg(target_endian = "little")]
620            {
621                self
622            }
623            #[cfg(not(target_endian = "little"))]
624            {
625                self.swap_bytes()
626            }
627        }
628
629        /// Checked integer addition. Computes `self + rhs`, returning `None`
630        /// if overflow occurred.
631        ///
632        /// # Examples
633        ///
634        /// ```
635        #[doc = concat!(
636            "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ",
637            "Some(", stringify!($SelfT), "::MAX - 1));"
638        )]
639        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
640        /// ```
641        #[stable(feature = "rust1", since = "1.0.0")]
642        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
643        #[must_use = "this returns the result of the operation, \
644                      without modifying the original"]
645        #[inline]
646        pub const fn checked_add(self, rhs: Self) -> Option<Self> {
647            // This used to use `overflowing_add`, but that means it ends up being
648            // a `wrapping_add`, losing some optimization opportunities. Notably,
649            // phrasing it this way helps `.checked_add(1)` optimize to a check
650            // against `MAX` and a `add nuw`.
651            // Per <https://github.com/rust-lang/rust/pull/124114#issuecomment-2066173305>,
652            // LLVM is happy to re-form the intrinsic later if useful.
653
654            if intrinsics::unlikely(intrinsics::add_with_overflow(self, rhs).1) {
655                None
656            } else {
657                // SAFETY: Just checked it doesn't overflow
658                Some(unsafe { intrinsics::unchecked_add(self, rhs) })
659            }
660        }
661
662        /// Strict integer addition. Computes `self + rhs`, panicking
663        /// if overflow occurred.
664        ///
665        /// # Panics
666        ///
667        /// ## Overflow behavior
668        ///
669        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
670        ///
671        /// # Examples
672        ///
673        /// ```
674        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
675        /// ```
676        ///
677        /// The following panics because of overflow:
678        ///
679        /// ```should_panic
680        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
681        /// ```
682        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
683        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
684        #[must_use = "this returns the result of the operation, \
685                      without modifying the original"]
686        #[inline]
687        #[track_caller]
688        pub const fn strict_add(self, rhs: Self) -> Self {
689            let (a, b) = self.overflowing_add(rhs);
690            if b { overflow_panic::add() } else { a }
691        }
692
693        /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
694        /// cannot occur.
695        ///
696        /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
697        /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
698        ///
699        /// If you're just trying to avoid the panic in debug mode, then **do not**
700        /// use this.  Instead, you're looking for [`wrapping_add`].
701        ///
702        /// # Safety
703        ///
704        /// This results in undefined behavior when
705        #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
706        /// i.e. when [`checked_add`] would return `None`.
707        ///
708        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
709        #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
710        #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
711        #[stable(feature = "unchecked_math", since = "1.79.0")]
712        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
713        #[must_use = "this returns the result of the operation, \
714                      without modifying the original"]
715        #[inline(always)]
716        #[track_caller]
717        pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
718            assert_unsafe_precondition!(
719                check_language_ub,
720                concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
721                (
722                    lhs: $SelfT = self,
723                    rhs: $SelfT = rhs,
724                ) => !lhs.overflowing_add(rhs).1,
725            );
726
727            // SAFETY: this is guaranteed to be safe by the caller.
728            unsafe {
729                intrinsics::unchecked_add(self, rhs)
730            }
731        }
732
733        /// Checked addition with a signed integer. Computes `self + rhs`,
734        /// returning `None` if overflow occurred.
735        ///
736        /// # Examples
737        ///
738        /// ```
739        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
740        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
741        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
742        /// ```
743        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
744        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
745        #[must_use = "this returns the result of the operation, \
746                      without modifying the original"]
747        #[inline]
748        pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
749            let (a, b) = self.overflowing_add_signed(rhs);
750            if intrinsics::unlikely(b) { None } else { Some(a) }
751        }
752
753        /// Strict addition with a signed integer. Computes `self + rhs`,
754        /// panicking if overflow occurred.
755        ///
756        /// # Panics
757        ///
758        /// ## Overflow behavior
759        ///
760        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
761        ///
762        /// # Examples
763        ///
764        /// ```
765        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_signed(2), 3);")]
766        /// ```
767        ///
768        /// The following panic because of overflow:
769        ///
770        /// ```should_panic
771        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_add_signed(-2);")]
772        /// ```
773        ///
774        /// ```should_panic
775        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")]
776        /// ```
777        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
778        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
779        #[must_use = "this returns the result of the operation, \
780                      without modifying the original"]
781        #[inline]
782        #[track_caller]
783        pub const fn strict_add_signed(self, rhs: $SignedT) -> Self {
784            let (a, b) = self.overflowing_add_signed(rhs);
785            if b { overflow_panic::add() } else { a }
786        }
787
788        /// Checked integer subtraction. Computes `self - rhs`, returning
789        /// `None` if overflow occurred.
790        ///
791        /// # Examples
792        ///
793        /// ```
794        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
795        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
796        /// ```
797        #[stable(feature = "rust1", since = "1.0.0")]
798        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
799        #[must_use = "this returns the result of the operation, \
800                      without modifying the original"]
801        #[inline]
802        pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
803            // Per PR#103299, there's no advantage to the `overflowing` intrinsic
804            // for *unsigned* subtraction and we just emit the manual check anyway.
805            // Thus, rather than using `overflowing_sub` that produces a wrapping
806            // subtraction, check it ourself so we can use an unchecked one.
807
808            if self < rhs {
809                None
810            } else {
811                // SAFETY: just checked this can't overflow
812                Some(unsafe { intrinsics::unchecked_sub(self, rhs) })
813            }
814        }
815
816        /// Strict integer subtraction. Computes `self - rhs`, panicking if
817        /// overflow occurred.
818        ///
819        /// # Panics
820        ///
821        /// ## Overflow behavior
822        ///
823        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
824        ///
825        /// # Examples
826        ///
827        /// ```
828        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub(1), 0);")]
829        /// ```
830        ///
831        /// The following panics because of overflow:
832        ///
833        /// ```should_panic
834        #[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")]
835        /// ```
836        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
837        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
838        #[must_use = "this returns the result of the operation, \
839                      without modifying the original"]
840        #[inline]
841        #[track_caller]
842        pub const fn strict_sub(self, rhs: Self) -> Self {
843            let (a, b) = self.overflowing_sub(rhs);
844            if b { overflow_panic::sub() } else { a }
845        }
846
847        /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
848        /// cannot occur.
849        ///
850        /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
851        /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
852        ///
853        /// If you're just trying to avoid the panic in debug mode, then **do not**
854        /// use this.  Instead, you're looking for [`wrapping_sub`].
855        ///
856        /// If you find yourself writing code like this:
857        ///
858        /// ```
859        /// # let foo = 30_u32;
860        /// # let bar = 20;
861        /// if foo >= bar {
862        ///     // SAFETY: just checked it will not overflow
863        ///     let diff = unsafe { foo.unchecked_sub(bar) };
864        ///     // ... use diff ...
865        /// }
866        /// ```
867        ///
868        /// Consider changing it to
869        ///
870        /// ```
871        /// # let foo = 30_u32;
872        /// # let bar = 20;
873        /// if let Some(diff) = foo.checked_sub(bar) {
874        ///     // ... use diff ...
875        /// }
876        /// ```
877        ///
878        /// As that does exactly the same thing -- including telling the optimizer
879        /// that the subtraction cannot overflow -- but avoids needing `unsafe`.
880        ///
881        /// # Safety
882        ///
883        /// This results in undefined behavior when
884        #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
885        /// i.e. when [`checked_sub`] would return `None`.
886        ///
887        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
888        #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
889        #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
890        #[stable(feature = "unchecked_math", since = "1.79.0")]
891        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
892        #[must_use = "this returns the result of the operation, \
893                      without modifying the original"]
894        #[inline(always)]
895        #[track_caller]
896        pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
897            assert_unsafe_precondition!(
898                check_language_ub,
899                concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
900                (
901                    lhs: $SelfT = self,
902                    rhs: $SelfT = rhs,
903                ) => !lhs.overflowing_sub(rhs).1,
904            );
905
906            // SAFETY: this is guaranteed to be safe by the caller.
907            unsafe {
908                intrinsics::unchecked_sub(self, rhs)
909            }
910        }
911
912        /// Checked subtraction with a signed integer. Computes `self - rhs`,
913        /// returning `None` if overflow occurred.
914        ///
915        /// # Examples
916        ///
917        /// ```
918        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(2), None);")]
919        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(-2), Some(3));")]
920        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_sub_signed(-4), None);")]
921        /// ```
922        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
923        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
924        #[must_use = "this returns the result of the operation, \
925                      without modifying the original"]
926        #[inline]
927        pub const fn checked_sub_signed(self, rhs: $SignedT) -> Option<Self> {
928            let (res, overflow) = self.overflowing_sub_signed(rhs);
929
930            if !overflow {
931                Some(res)
932            } else {
933                None
934            }
935        }
936
937        /// Strict subtraction with a signed integer. Computes `self - rhs`,
938        /// panicking if overflow occurred.
939        ///
940        /// # Panics
941        ///
942        /// ## Overflow behavior
943        ///
944        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
945        ///
946        /// # Examples
947        ///
948        /// ```
949        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".strict_sub_signed(2), 1);")]
950        /// ```
951        ///
952        /// The following panic because of overflow:
953        ///
954        /// ```should_panic
955        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_sub_signed(2);")]
956        /// ```
957        ///
958        /// ```should_panic
959        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX).strict_sub_signed(-1);")]
960        /// ```
961        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
962        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
963        #[must_use = "this returns the result of the operation, \
964                      without modifying the original"]
965        #[inline]
966        #[track_caller]
967        pub const fn strict_sub_signed(self, rhs: $SignedT) -> Self {
968            let (a, b) = self.overflowing_sub_signed(rhs);
969            if b { overflow_panic::sub() } else { a }
970        }
971
972        #[doc = concat!(
973            "Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`",
974            stringify!($SignedT), "`], returning `None` if overflow occurred."
975        )]
976        ///
977        /// # Examples
978        ///
979        /// ```
980        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")]
981        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")]
982        #[doc = concat!(
983            "assert_eq!(",
984            stringify!($SelfT),
985            "::MAX.checked_signed_diff(",
986            stringify!($SignedT),
987            "::MAX as ",
988            stringify!($SelfT),
989            "), None);"
990        )]
991        #[doc = concat!(
992            "assert_eq!((",
993            stringify!($SignedT),
994            "::MAX as ",
995            stringify!($SelfT),
996            ").checked_signed_diff(",
997            stringify!($SelfT),
998            "::MAX), Some(",
999            stringify!($SignedT),
1000            "::MIN));"
1001        )]
1002        #[doc = concat!(
1003            "assert_eq!((",
1004            stringify!($SignedT),
1005            "::MAX as ",
1006            stringify!($SelfT),
1007            " + 1).checked_signed_diff(0), None);"
1008        )]
1009        #[doc = concat!(
1010            "assert_eq!(",
1011            stringify!($SelfT),
1012            "::MAX.checked_signed_diff(",
1013            stringify!($SelfT),
1014            "::MAX), Some(0));"
1015        )]
1016        /// ```
1017        #[stable(feature = "unsigned_signed_diff", since = "1.91.0")]
1018        #[rustc_const_stable(feature = "unsigned_signed_diff", since = "1.91.0")]
1019        #[inline]
1020        pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
1021            let res = self.wrapping_sub(rhs) as $SignedT;
1022            let overflow = (self >= rhs) == (res < 0);
1023
1024            if !overflow {
1025                Some(res)
1026            } else {
1027                None
1028            }
1029        }
1030
1031        /// Checked integer multiplication. Computes `self * rhs`, returning
1032        /// `None` if overflow occurred.
1033        ///
1034        /// # Examples
1035        ///
1036        /// ```
1037        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")]
1038        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
1039        /// ```
1040        #[stable(feature = "rust1", since = "1.0.0")]
1041        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1042        #[must_use = "this returns the result of the operation, \
1043                      without modifying the original"]
1044        #[inline]
1045        pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
1046            let (a, b) = self.overflowing_mul(rhs);
1047            if intrinsics::unlikely(b) { None } else { Some(a) }
1048        }
1049
1050        /// Strict integer multiplication. Computes `self * rhs`, panicking if
1051        /// overflow occurred.
1052        ///
1053        /// # Panics
1054        ///
1055        /// ## Overflow behavior
1056        ///
1057        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1058        ///
1059        /// # Examples
1060        ///
1061        /// ```
1062        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_mul(1), 5);")]
1063        /// ```
1064        ///
1065        /// The following panics because of overflow:
1066        ///
1067        /// ``` should_panic
1068        #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
1069        /// ```
1070        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1071        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1072        #[must_use = "this returns the result of the operation, \
1073                      without modifying the original"]
1074        #[inline]
1075        #[track_caller]
1076        pub const fn strict_mul(self, rhs: Self) -> Self {
1077            let (a, b) = self.overflowing_mul(rhs);
1078            if b { overflow_panic::mul() } else { a }
1079        }
1080
1081        /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
1082        /// cannot occur.
1083        ///
1084        /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
1085        /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
1086        ///
1087        /// If you're just trying to avoid the panic in debug mode, then **do not**
1088        /// use this.  Instead, you're looking for [`wrapping_mul`].
1089        ///
1090        /// # Safety
1091        ///
1092        /// This results in undefined behavior when
1093        #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
1094        /// i.e. when [`checked_mul`] would return `None`.
1095        ///
1096        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
1097        #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
1098        #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
1099        #[stable(feature = "unchecked_math", since = "1.79.0")]
1100        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
1101        #[must_use = "this returns the result of the operation, \
1102                      without modifying the original"]
1103        #[inline(always)]
1104        #[track_caller]
1105        pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
1106            assert_unsafe_precondition!(
1107                check_language_ub,
1108                concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
1109                (
1110                    lhs: $SelfT = self,
1111                    rhs: $SelfT = rhs,
1112                ) => !lhs.overflowing_mul(rhs).1,
1113            );
1114
1115            // SAFETY: this is guaranteed to be safe by the caller.
1116            unsafe {
1117                intrinsics::unchecked_mul(self, rhs)
1118            }
1119        }
1120
1121        /// Checked integer division. Computes `self / rhs`, returning `None`
1122        /// if `rhs == 0`.
1123        ///
1124        /// # Examples
1125        ///
1126        /// ```
1127        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
1128        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
1129        /// ```
1130        #[stable(feature = "rust1", since = "1.0.0")]
1131        #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1132        #[must_use = "this returns the result of the operation, \
1133                      without modifying the original"]
1134        #[inline]
1135        pub const fn checked_div(self, rhs: Self) -> Option<Self> {
1136            if intrinsics::unlikely(rhs == 0) {
1137                None
1138            } else {
1139                // SAFETY: div by zero has been checked above and unsigned types have no other
1140                // failure modes for division
1141                Some(unsafe { intrinsics::unchecked_div(self, rhs) })
1142            }
1143        }
1144
1145        /// Strict integer division. Computes `self / rhs`.
1146        ///
1147        /// Strict division on unsigned types is just normal division. There's no
1148        /// way overflow could ever happen. This function exists so that all
1149        /// operations are accounted for in the strict operations.
1150        ///
1151        /// # Panics
1152        ///
1153        /// This function will panic if `rhs` is zero.
1154        ///
1155        /// # Examples
1156        ///
1157        /// ```
1158        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div(10), 10);")]
1159        /// ```
1160        ///
1161        /// The following panics because of division by zero:
1162        ///
1163        /// ```should_panic
1164        #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
1165        /// ```
1166        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1167        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1168        #[must_use = "this returns the result of the operation, \
1169                      without modifying the original"]
1170        #[inline(always)]
1171        #[track_caller]
1172        pub const fn strict_div(self, rhs: Self) -> Self {
1173            self / rhs
1174        }
1175
1176        /// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None`
1177        /// if `rhs == 0`.
1178        ///
1179        /// # Examples
1180        ///
1181        /// ```
1182        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
1183        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
1184        /// ```
1185        #[stable(feature = "euclidean_division", since = "1.38.0")]
1186        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1187        #[must_use = "this returns the result of the operation, \
1188                      without modifying the original"]
1189        #[inline]
1190        pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
1191            if intrinsics::unlikely(rhs == 0) {
1192                None
1193            } else {
1194                Some(self.div_euclid(rhs))
1195            }
1196        }
1197
1198        /// Strict Euclidean division. Computes `self.div_euclid(rhs)`.
1199        ///
1200        /// Strict division on unsigned types is just normal division. There's no
1201        /// way overflow could ever happen. This function exists so that all
1202        /// operations are accounted for in the strict operations. Since, for the
1203        /// positive integers, all common definitions of division are equal, this
1204        /// is exactly equal to `self.strict_div(rhs)`.
1205        ///
1206        /// # Panics
1207        ///
1208        /// This function will panic if `rhs` is zero.
1209        ///
1210        /// # Examples
1211        ///
1212        /// ```
1213        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div_euclid(10), 10);")]
1214        /// ```
1215        /// The following panics because of division by zero:
1216        ///
1217        /// ```should_panic
1218        #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
1219        /// ```
1220        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1221        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1222        #[must_use = "this returns the result of the operation, \
1223                      without modifying the original"]
1224        #[inline(always)]
1225        #[track_caller]
1226        pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1227            self / rhs
1228        }
1229
1230        /// Checked integer division without remainder. Computes `self / rhs`,
1231        /// returning `None` if `rhs == 0` or if `self % rhs != 0`.
1232        ///
1233        /// # Examples
1234        ///
1235        /// ```
1236        /// #![feature(exact_div)]
1237        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(2), Some(32));")]
1238        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(32), Some(2));")]
1239        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(0), None);")]
1240        #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".checked_div_exact(2), None);")]
1241        /// ```
1242        #[unstable(
1243            feature = "exact_div",
1244            issue = "139911",
1245        )]
1246        #[must_use = "this returns the result of the operation, \
1247                      without modifying the original"]
1248        #[inline]
1249        pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
1250            if intrinsics::unlikely(rhs == 0) {
1251                None
1252            } else {
1253                // SAFETY: division by zero is checked above
1254                unsafe {
1255                    if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1256                        None
1257                    } else {
1258                        Some(intrinsics::exact_div(self, rhs))
1259                    }
1260                }
1261            }
1262        }
1263
1264        /// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
1265        ///
1266        /// # Panics
1267        ///
1268        /// This function will panic  if `rhs == 0`.
1269        ///
1270        /// # Examples
1271        ///
1272        /// ```
1273        /// #![feature(exact_div)]
1274        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
1275        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
1276        #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
1277        /// ```
1278        #[unstable(
1279            feature = "exact_div",
1280            issue = "139911",
1281        )]
1282        #[must_use = "this returns the result of the operation, \
1283                      without modifying the original"]
1284        #[inline]
1285        #[rustc_inherit_overflow_checks]
1286        pub const fn div_exact(self, rhs: Self) -> Option<Self> {
1287            if self % rhs != 0 {
1288                None
1289            } else {
1290                Some(self / rhs)
1291            }
1292        }
1293
1294        /// Unchecked integer division without remainder. Computes `self / rhs`.
1295        ///
1296        /// # Safety
1297        ///
1298        /// This results in undefined behavior when `rhs == 0` or `self % rhs != 0`,
1299        /// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
1300        #[unstable(
1301            feature = "exact_div",
1302            issue = "139911",
1303        )]
1304        #[must_use = "this returns the result of the operation, \
1305                      without modifying the original"]
1306        #[inline]
1307        pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
1308            assert_unsafe_precondition!(
1309                check_language_ub,
1310                concat!(stringify!($SelfT), "::unchecked_div_exact divide by zero or leave a remainder"),
1311                (
1312                    lhs: $SelfT = self,
1313                    rhs: $SelfT = rhs,
1314                ) => rhs > 0 && lhs % rhs == 0,
1315            );
1316            // SAFETY: Same precondition
1317            unsafe { intrinsics::exact_div(self, rhs) }
1318        }
1319
1320        /// Checked integer remainder. Computes `self % rhs`, returning `None`
1321        /// if `rhs == 0`.
1322        ///
1323        /// # Examples
1324        ///
1325        /// ```
1326        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1327        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1328        /// ```
1329        #[stable(feature = "wrapping", since = "1.7.0")]
1330        #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1331        #[must_use = "this returns the result of the operation, \
1332                      without modifying the original"]
1333        #[inline]
1334        pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1335            if intrinsics::unlikely(rhs == 0) {
1336                None
1337            } else {
1338                // SAFETY: div by zero has been checked above and unsigned types have no other
1339                // failure modes for division
1340                Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1341            }
1342        }
1343
1344        /// Strict integer remainder. Computes `self % rhs`.
1345        ///
1346        /// Strict remainder calculation on unsigned types is just the regular
1347        /// remainder calculation. There's no way overflow could ever happen.
1348        /// This function exists so that all operations are accounted for in the
1349        /// strict operations.
1350        ///
1351        /// # Panics
1352        ///
1353        /// This function will panic if `rhs` is zero.
1354        ///
1355        /// # Examples
1356        ///
1357        /// ```
1358        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem(10), 0);")]
1359        /// ```
1360        ///
1361        /// The following panics because of division by zero:
1362        ///
1363        /// ```should_panic
1364        #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1365        /// ```
1366        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1367        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1368        #[must_use = "this returns the result of the operation, \
1369                      without modifying the original"]
1370        #[inline(always)]
1371        #[track_caller]
1372        pub const fn strict_rem(self, rhs: Self) -> Self {
1373            self % rhs
1374        }
1375
1376        /// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None`
1377        /// if `rhs == 0`.
1378        ///
1379        /// # Examples
1380        ///
1381        /// ```
1382        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1383        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1384        /// ```
1385        #[stable(feature = "euclidean_division", since = "1.38.0")]
1386        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1387        #[must_use = "this returns the result of the operation, \
1388                      without modifying the original"]
1389        #[inline]
1390        pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1391            if intrinsics::unlikely(rhs == 0) {
1392                None
1393            } else {
1394                Some(self.rem_euclid(rhs))
1395            }
1396        }
1397
1398        /// Strict Euclidean modulo. Computes `self.rem_euclid(rhs)`.
1399        ///
1400        /// Strict modulo calculation on unsigned types is just the regular
1401        /// remainder calculation. There's no way overflow could ever happen.
1402        /// This function exists so that all operations are accounted for in the
1403        /// strict operations. Since, for the positive integers, all common
1404        /// definitions of division are equal, this is exactly equal to
1405        /// `self.strict_rem(rhs)`.
1406        ///
1407        /// # Panics
1408        ///
1409        /// This function will panic if `rhs` is zero.
1410        ///
1411        /// # Examples
1412        ///
1413        /// ```
1414        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem_euclid(10), 0);")]
1415        /// ```
1416        ///
1417        /// The following panics because of division by zero:
1418        ///
1419        /// ```should_panic
1420        #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1421        /// ```
1422        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1423        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1424        #[must_use = "this returns the result of the operation, \
1425                      without modifying the original"]
1426        #[inline(always)]
1427        #[track_caller]
1428        pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1429            self % rhs
1430        }
1431
1432        /// Same value as `self | other`, but UB if any bit position is set in both inputs.
1433        ///
1434        /// This is a situational micro-optimization for places where you'd rather
1435        /// use addition on some platforms and bitwise or on other platforms, based
1436        /// on exactly which instructions combine better with whatever else you're
1437        /// doing.  Note that there's no reason to bother using this for places
1438        /// where it's clear from the operations involved that they can't overlap.
1439        /// For example, if you're combining `u16`s into a `u32` with
1440        /// `((a as u32) << 16) | (b as u32)`, that's fine, as the backend will
1441        /// know those sides of the `|` are disjoint without needing help.
1442        ///
1443        /// # Examples
1444        ///
1445        /// ```
1446        /// #![feature(disjoint_bitor)]
1447        ///
1448        /// // SAFETY: `1` and `4` have no bits in common.
1449        /// unsafe {
1450        #[doc = concat!("    assert_eq!(1_", stringify!($SelfT), ".unchecked_disjoint_bitor(4), 5);")]
1451        /// }
1452        /// ```
1453        ///
1454        /// # Safety
1455        ///
1456        /// Requires that `(self & other) == 0`, otherwise it's immediate UB.
1457        ///
1458        /// Equivalently, requires that `(self | other) == (self + other)`.
1459        #[unstable(feature = "disjoint_bitor", issue = "135758")]
1460        #[rustc_const_unstable(feature = "disjoint_bitor", issue = "135758")]
1461        #[inline]
1462        pub const unsafe fn unchecked_disjoint_bitor(self, other: Self) -> Self {
1463            assert_unsafe_precondition!(
1464                check_language_ub,
1465                concat!(stringify!($SelfT), "::unchecked_disjoint_bitor cannot have overlapping bits"),
1466                (
1467                    lhs: $SelfT = self,
1468                    rhs: $SelfT = other,
1469                ) => (lhs & rhs) == 0,
1470            );
1471
1472            // SAFETY: Same precondition
1473            unsafe { intrinsics::disjoint_bitor(self, other) }
1474        }
1475
1476        /// Returns the logarithm of the number with respect to an arbitrary base,
1477        /// rounded down.
1478        ///
1479        /// This method might not be optimized owing to implementation details;
1480        /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
1481        /// can produce results more efficiently for base 10.
1482        ///
1483        /// # Panics
1484        ///
1485        /// This function will panic if `self` is zero, or if `base` is less than 2.
1486        ///
1487        /// # Examples
1488        ///
1489        /// ```
1490        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
1491        /// ```
1492        #[stable(feature = "int_log", since = "1.67.0")]
1493        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1494        #[must_use = "this returns the result of the operation, \
1495                      without modifying the original"]
1496        #[inline]
1497        #[track_caller]
1498        pub const fn ilog(self, base: Self) -> u32 {
1499            assert!(base >= 2, "base of integer logarithm must be at least 2");
1500            if let Some(log) = self.checked_ilog(base) {
1501                log
1502            } else {
1503                int_log10::panic_for_nonpositive_argument()
1504            }
1505        }
1506
1507        /// Returns the base 2 logarithm of the number, rounded down.
1508        ///
1509        /// # Panics
1510        ///
1511        /// This function will panic if `self` is zero.
1512        ///
1513        /// # Examples
1514        ///
1515        /// ```
1516        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
1517        /// ```
1518        #[stable(feature = "int_log", since = "1.67.0")]
1519        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1520        #[must_use = "this returns the result of the operation, \
1521                      without modifying the original"]
1522        #[inline]
1523        #[track_caller]
1524        pub const fn ilog2(self) -> u32 {
1525            if let Some(log) = self.checked_ilog2() {
1526                log
1527            } else {
1528                int_log10::panic_for_nonpositive_argument()
1529            }
1530        }
1531
1532        /// Returns the base 10 logarithm of the number, rounded down.
1533        ///
1534        /// # Panics
1535        ///
1536        /// This function will panic if `self` is zero.
1537        ///
1538        /// # Example
1539        ///
1540        /// ```
1541        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
1542        /// ```
1543        #[stable(feature = "int_log", since = "1.67.0")]
1544        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1545        #[must_use = "this returns the result of the operation, \
1546                      without modifying the original"]
1547        #[inline]
1548        #[track_caller]
1549        pub const fn ilog10(self) -> u32 {
1550            if let Some(log) = self.checked_ilog10() {
1551                log
1552            } else {
1553                int_log10::panic_for_nonpositive_argument()
1554            }
1555        }
1556
1557        /// Returns the logarithm of the number with respect to an arbitrary base,
1558        /// rounded down.
1559        ///
1560        /// Returns `None` if the number is zero, or if the base is not at least 2.
1561        ///
1562        /// This method might not be optimized owing to implementation details;
1563        /// `checked_ilog2` can produce results more efficiently for base 2, and
1564        /// `checked_ilog10` can produce results more efficiently for base 10.
1565        ///
1566        /// # Examples
1567        ///
1568        /// ```
1569        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
1570        /// ```
1571        #[stable(feature = "int_log", since = "1.67.0")]
1572        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1573        #[must_use = "this returns the result of the operation, \
1574                      without modifying the original"]
1575        #[inline]
1576        pub const fn checked_ilog(self, base: Self) -> Option<u32> {
1577            // Inform compiler of optimizations when the base is known at
1578            // compile time and there's a cheaper method available.
1579            //
1580            // Note: Like all optimizations, this is not guaranteed to be
1581            // applied by the compiler. If you want those specific bases,
1582            // use `.checked_ilog2()` or `.checked_ilog10()` directly.
1583            if core::intrinsics::is_val_statically_known(base) {
1584                if base == 2 {
1585                    return self.checked_ilog2();
1586                } else if base == 10 {
1587                    return self.checked_ilog10();
1588                }
1589            }
1590
1591            if self <= 0 || base <= 1 {
1592                None
1593            } else if self < base {
1594                Some(0)
1595            } else {
1596                // Since base >= self, n >= 1
1597                let mut n = 1;
1598                let mut r = base;
1599
1600                // Optimization for 128 bit wide integers.
1601                if Self::BITS == 128 {
1602                    // The following is a correct lower bound for ⌊log(base,self)⌋ because
1603                    //
1604                    // log(base,self) = log(2,self) / log(2,base)
1605                    //                ≥ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1)
1606                    //
1607                    // hence
1608                    //
1609                    // ⌊log(base,self)⌋ ≥ ⌊ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) ⌋ .
1610                    n = self.ilog2() / (base.ilog2() + 1);
1611                    r = base.pow(n);
1612                }
1613
1614                while r <= self / base {
1615                    n += 1;
1616                    r *= base;
1617                }
1618                Some(n)
1619            }
1620        }
1621
1622        /// Returns the base 2 logarithm of the number, rounded down.
1623        ///
1624        /// Returns `None` if the number is zero.
1625        ///
1626        /// # Examples
1627        ///
1628        /// ```
1629        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
1630        /// ```
1631        #[stable(feature = "int_log", since = "1.67.0")]
1632        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1633        #[must_use = "this returns the result of the operation, \
1634                      without modifying the original"]
1635        #[inline]
1636        pub const fn checked_ilog2(self) -> Option<u32> {
1637            match NonZero::new(self) {
1638                Some(x) => Some(x.ilog2()),
1639                None => None,
1640            }
1641        }
1642
1643        /// Returns the base 10 logarithm of the number, rounded down.
1644        ///
1645        /// Returns `None` if the number is zero.
1646        ///
1647        /// # Examples
1648        ///
1649        /// ```
1650        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
1651        /// ```
1652        #[stable(feature = "int_log", since = "1.67.0")]
1653        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1654        #[must_use = "this returns the result of the operation, \
1655                      without modifying the original"]
1656        #[inline]
1657        pub const fn checked_ilog10(self) -> Option<u32> {
1658            match NonZero::new(self) {
1659                Some(x) => Some(x.ilog10()),
1660                None => None,
1661            }
1662        }
1663
1664        /// Checked negation. Computes `-self`, returning `None` unless `self ==
1665        /// 0`.
1666        ///
1667        /// Note that negating any positive integer will overflow.
1668        ///
1669        /// # Examples
1670        ///
1671        /// ```
1672        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
1673        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
1674        /// ```
1675        #[stable(feature = "wrapping", since = "1.7.0")]
1676        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1677        #[must_use = "this returns the result of the operation, \
1678                      without modifying the original"]
1679        #[inline]
1680        pub const fn checked_neg(self) -> Option<Self> {
1681            let (a, b) = self.overflowing_neg();
1682            if intrinsics::unlikely(b) { None } else { Some(a) }
1683        }
1684
1685        /// Strict negation. Computes `-self`, panicking unless `self ==
1686        /// 0`.
1687        ///
1688        /// Note that negating any positive integer will overflow.
1689        ///
1690        /// # Panics
1691        ///
1692        /// ## Overflow behavior
1693        ///
1694        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1695        ///
1696        /// # Examples
1697        ///
1698        /// ```
1699        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".strict_neg(), 0);")]
1700        /// ```
1701        ///
1702        /// The following panics because of overflow:
1703        ///
1704        /// ```should_panic
1705        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
1706        /// ```
1707        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1708        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1709        #[must_use = "this returns the result of the operation, \
1710                      without modifying the original"]
1711        #[inline]
1712        #[track_caller]
1713        pub const fn strict_neg(self) -> Self {
1714            let (a, b) = self.overflowing_neg();
1715            if b { overflow_panic::neg() } else { a }
1716        }
1717
1718        /// Checked shift left. Computes `self << rhs`, returning `None`
1719        /// if `rhs` is larger than or equal to the number of bits in `self`.
1720        ///
1721        /// # Examples
1722        ///
1723        /// ```
1724        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1725        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
1726        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1727        /// ```
1728        #[stable(feature = "wrapping", since = "1.7.0")]
1729        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1730        #[must_use = "this returns the result of the operation, \
1731                      without modifying the original"]
1732        #[inline]
1733        pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1734            // Not using overflowing_shl as that's a wrapping shift
1735            if rhs < Self::BITS {
1736                // SAFETY: just checked the RHS is in-range
1737                Some(unsafe { self.unchecked_shl(rhs) })
1738            } else {
1739                None
1740            }
1741        }
1742
1743        /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1744        /// than or equal to the number of bits in `self`.
1745        ///
1746        /// # Panics
1747        ///
1748        /// ## Overflow behavior
1749        ///
1750        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1751        ///
1752        /// # Examples
1753        ///
1754        /// ```
1755        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1756        /// ```
1757        ///
1758        /// The following panics because of overflow:
1759        ///
1760        /// ```should_panic
1761        #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")]
1762        /// ```
1763        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1764        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1765        #[must_use = "this returns the result of the operation, \
1766                      without modifying the original"]
1767        #[inline]
1768        #[track_caller]
1769        pub const fn strict_shl(self, rhs: u32) -> Self {
1770            let (a, b) = self.overflowing_shl(rhs);
1771            if b { overflow_panic::shl() } else { a }
1772        }
1773
1774        /// Unchecked shift left. Computes `self << rhs`, assuming that
1775        /// `rhs` is less than the number of bits in `self`.
1776        ///
1777        /// # Safety
1778        ///
1779        /// This results in undefined behavior if `rhs` is larger than
1780        /// or equal to the number of bits in `self`,
1781        /// i.e. when [`checked_shl`] would return `None`.
1782        ///
1783        #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1784        #[unstable(
1785            feature = "unchecked_shifts",
1786            reason = "niche optimization path",
1787            issue = "85122",
1788        )]
1789        #[must_use = "this returns the result of the operation, \
1790                      without modifying the original"]
1791        #[inline(always)]
1792        #[track_caller]
1793        pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1794            assert_unsafe_precondition!(
1795                check_language_ub,
1796                concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1797                (
1798                    rhs: u32 = rhs,
1799                ) => rhs < <$ActualT>::BITS,
1800            );
1801
1802            // SAFETY: this is guaranteed to be safe by the caller.
1803            unsafe {
1804                intrinsics::unchecked_shl(self, rhs)
1805            }
1806        }
1807
1808        /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1809        ///
1810        /// If `rhs` is larger or equal to the number of bits in `self`,
1811        /// the entire value is shifted out, and `0` is returned.
1812        ///
1813        /// # Examples
1814        ///
1815        /// ```
1816        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1817        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1818        /// ```
1819        #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1820        #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1821        #[must_use = "this returns the result of the operation, \
1822                      without modifying the original"]
1823        #[inline]
1824        pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1825            if rhs < Self::BITS {
1826                // SAFETY:
1827                // rhs is just checked to be in-range above
1828                unsafe { self.unchecked_shl(rhs) }
1829            } else {
1830                0
1831            }
1832        }
1833
1834        /// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
1835        ///
1836        /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
1837        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1838        /// Otherwise, returns `Some(self << rhs)`.
1839        ///
1840        /// # Examples
1841        ///
1842        /// ```
1843        /// #![feature(exact_bitshifts)]
1844        ///
1845        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
1846        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(129), None);")]
1847        /// ```
1848        #[unstable(feature = "exact_bitshifts", issue = "144336")]
1849        #[must_use = "this returns the result of the operation, \
1850                      without modifying the original"]
1851        #[inline]
1852        pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
1853            if rhs <= self.leading_zeros() && rhs < <$SelfT>::BITS {
1854                // SAFETY: rhs is checked above
1855                Some(unsafe { self.unchecked_shl(rhs) })
1856            } else {
1857                None
1858            }
1859        }
1860
1861        /// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
1862        /// losslessly reversed `rhs` cannot be larger than
1863        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1864        ///
1865        /// # Safety
1866        ///
1867        /// This results in undefined behavior when `rhs > self.leading_zeros() || rhs >=
1868        #[doc = concat!(stringify!($SelfT), "::BITS`")]
1869        /// i.e. when
1870        #[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
1871        /// would return `None`.
1872        #[unstable(feature = "exact_bitshifts", issue = "144336")]
1873        #[must_use = "this returns the result of the operation, \
1874                      without modifying the original"]
1875        #[inline]
1876        pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
1877            assert_unsafe_precondition!(
1878                check_library_ub,
1879                concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out non-zero bits"),
1880                (
1881                    zeros: u32 = self.leading_zeros(),
1882                    bits: u32 =  <$SelfT>::BITS,
1883                    rhs: u32 = rhs,
1884                ) => rhs <= zeros && rhs < bits,
1885            );
1886
1887            // SAFETY: this is guaranteed to be safe by the caller
1888            unsafe { self.unchecked_shl(rhs) }
1889        }
1890
1891        /// Checked shift right. Computes `self >> rhs`, returning `None`
1892        /// if `rhs` is larger than or equal to the number of bits in `self`.
1893        ///
1894        /// # Examples
1895        ///
1896        /// ```
1897        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
1898        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")]
1899        /// ```
1900        #[stable(feature = "wrapping", since = "1.7.0")]
1901        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1902        #[must_use = "this returns the result of the operation, \
1903                      without modifying the original"]
1904        #[inline]
1905        pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
1906            // Not using overflowing_shr as that's a wrapping shift
1907            if rhs < Self::BITS {
1908                // SAFETY: just checked the RHS is in-range
1909                Some(unsafe { self.unchecked_shr(rhs) })
1910            } else {
1911                None
1912            }
1913        }
1914
1915        /// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
1916        /// larger than or equal to the number of bits in `self`.
1917        ///
1918        /// # Panics
1919        ///
1920        /// ## Overflow behavior
1921        ///
1922        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1923        ///
1924        /// # Examples
1925        ///
1926        /// ```
1927        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
1928        /// ```
1929        ///
1930        /// The following panics because of overflow:
1931        ///
1932        /// ```should_panic
1933        #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")]
1934        /// ```
1935        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1936        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1937        #[must_use = "this returns the result of the operation, \
1938                      without modifying the original"]
1939        #[inline]
1940        #[track_caller]
1941        pub const fn strict_shr(self, rhs: u32) -> Self {
1942            let (a, b) = self.overflowing_shr(rhs);
1943            if b { overflow_panic::shr() } else { a }
1944        }
1945
1946        /// Unchecked shift right. Computes `self >> rhs`, assuming that
1947        /// `rhs` is less than the number of bits in `self`.
1948        ///
1949        /// # Safety
1950        ///
1951        /// This results in undefined behavior if `rhs` is larger than
1952        /// or equal to the number of bits in `self`,
1953        /// i.e. when [`checked_shr`] would return `None`.
1954        ///
1955        #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
1956        #[unstable(
1957            feature = "unchecked_shifts",
1958            reason = "niche optimization path",
1959            issue = "85122",
1960        )]
1961        #[must_use = "this returns the result of the operation, \
1962                      without modifying the original"]
1963        #[inline(always)]
1964        #[track_caller]
1965        pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
1966            assert_unsafe_precondition!(
1967                check_language_ub,
1968                concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
1969                (
1970                    rhs: u32 = rhs,
1971                ) => rhs < <$ActualT>::BITS,
1972            );
1973
1974            // SAFETY: this is guaranteed to be safe by the caller.
1975            unsafe {
1976                intrinsics::unchecked_shr(self, rhs)
1977            }
1978        }
1979
1980        /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
1981        ///
1982        /// If `rhs` is larger or equal to the number of bits in `self`,
1983        /// the entire value is shifted out, and `0` is returned.
1984        ///
1985        /// # Examples
1986        ///
1987        /// ```
1988        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
1989        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(129), 0);")]
1990        /// ```
1991        #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1992        #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1993        #[must_use = "this returns the result of the operation, \
1994                      without modifying the original"]
1995        #[inline]
1996        pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
1997            if rhs < Self::BITS {
1998                // SAFETY:
1999                // rhs is just checked to be in-range above
2000                unsafe { self.unchecked_shr(rhs) }
2001            } else {
2002                0
2003            }
2004        }
2005
2006        /// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
2007        ///
2008        /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
2009        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2010        /// Otherwise, returns `Some(self >> rhs)`.
2011        ///
2012        /// # Examples
2013        ///
2014        /// ```
2015        /// #![feature(exact_bitshifts)]
2016        ///
2017        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
2018        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
2019        /// ```
2020        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2021        #[must_use = "this returns the result of the operation, \
2022                      without modifying the original"]
2023        #[inline]
2024        pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
2025            if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
2026                // SAFETY: rhs is checked above
2027                Some(unsafe { self.unchecked_shr(rhs) })
2028            } else {
2029                None
2030            }
2031        }
2032
2033        /// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
2034        /// losslessly reversed and `rhs` cannot be larger than
2035        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2036        ///
2037        /// # Safety
2038        ///
2039        /// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
2040        #[doc = concat!(stringify!($SelfT), "::BITS`")]
2041        /// i.e. when
2042        #[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
2043        /// would return `None`.
2044        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2045        #[must_use = "this returns the result of the operation, \
2046                      without modifying the original"]
2047        #[inline]
2048        pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
2049            assert_unsafe_precondition!(
2050                check_library_ub,
2051                concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
2052                (
2053                    zeros: u32 = self.trailing_zeros(),
2054                    bits: u32 =  <$SelfT>::BITS,
2055                    rhs: u32 = rhs,
2056                ) => rhs <= zeros && rhs < bits,
2057            );
2058
2059            // SAFETY: this is guaranteed to be safe by the caller
2060            unsafe { self.unchecked_shr(rhs) }
2061        }
2062
2063        /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
2064        /// overflow occurred.
2065        ///
2066        /// # Examples
2067        ///
2068        /// ```
2069        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
2070        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
2071        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
2072        /// ```
2073        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2074        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2075        #[must_use = "this returns the result of the operation, \
2076                      without modifying the original"]
2077        #[inline]
2078        pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
2079            if exp == 0 {
2080                return Some(1);
2081            }
2082            let mut base = self;
2083            let mut acc: Self = 1;
2084
2085            loop {
2086                if (exp & 1) == 1 {
2087                    acc = try_opt!(acc.checked_mul(base));
2088                    // since exp!=0, finally the exp must be 1.
2089                    if exp == 1 {
2090                        return Some(acc);
2091                    }
2092                }
2093                exp /= 2;
2094                base = try_opt!(base.checked_mul(base));
2095            }
2096        }
2097
2098        /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
2099        /// overflow occurred.
2100        ///
2101        /// # Panics
2102        ///
2103        /// ## Overflow behavior
2104        ///
2105        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
2106        ///
2107        /// # Examples
2108        ///
2109        /// ```
2110        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".strict_pow(5), 32);")]
2111        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
2112        /// ```
2113        ///
2114        /// The following panics because of overflow:
2115        ///
2116        /// ```should_panic
2117        #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
2118        /// ```
2119        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
2120        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
2121        #[must_use = "this returns the result of the operation, \
2122                      without modifying the original"]
2123        #[inline]
2124        #[track_caller]
2125        pub const fn strict_pow(self, mut exp: u32) -> Self {
2126            if exp == 0 {
2127                return 1;
2128            }
2129            let mut base = self;
2130            let mut acc: Self = 1;
2131
2132            loop {
2133                if (exp & 1) == 1 {
2134                    acc = acc.strict_mul(base);
2135                    // since exp!=0, finally the exp must be 1.
2136                    if exp == 1 {
2137                        return acc;
2138                    }
2139                }
2140                exp /= 2;
2141                base = base.strict_mul(base);
2142            }
2143        }
2144
2145        /// Saturating integer addition. Computes `self + rhs`, saturating at
2146        /// the numeric bounds instead of overflowing.
2147        ///
2148        /// # Examples
2149        ///
2150        /// ```
2151        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
2152        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")]
2153        /// ```
2154        #[stable(feature = "rust1", since = "1.0.0")]
2155        #[must_use = "this returns the result of the operation, \
2156                      without modifying the original"]
2157        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2158        #[inline(always)]
2159        pub const fn saturating_add(self, rhs: Self) -> Self {
2160            intrinsics::saturating_add(self, rhs)
2161        }
2162
2163        /// Saturating addition with a signed integer. Computes `self + rhs`,
2164        /// saturating at the numeric bounds instead of overflowing.
2165        ///
2166        /// # Examples
2167        ///
2168        /// ```
2169        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
2170        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
2171        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
2172        /// ```
2173        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2174        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2175        #[must_use = "this returns the result of the operation, \
2176                      without modifying the original"]
2177        #[inline]
2178        pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
2179            let (res, overflow) = self.overflowing_add(rhs as Self);
2180            if overflow == (rhs < 0) {
2181                res
2182            } else if overflow {
2183                Self::MAX
2184            } else {
2185                0
2186            }
2187        }
2188
2189        /// Saturating integer subtraction. Computes `self - rhs`, saturating
2190        /// at the numeric bounds instead of overflowing.
2191        ///
2192        /// # Examples
2193        ///
2194        /// ```
2195        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
2196        #[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
2197        /// ```
2198        #[stable(feature = "rust1", since = "1.0.0")]
2199        #[must_use = "this returns the result of the operation, \
2200                      without modifying the original"]
2201        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2202        #[inline(always)]
2203        pub const fn saturating_sub(self, rhs: Self) -> Self {
2204            intrinsics::saturating_sub(self, rhs)
2205        }
2206
2207        /// Saturating integer subtraction. Computes `self` - `rhs`, saturating at
2208        /// the numeric bounds instead of overflowing.
2209        ///
2210        /// # Examples
2211        ///
2212        /// ```
2213        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(2), 0);")]
2214        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(-2), 3);")]
2215        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_sub_signed(-4), ", stringify!($SelfT), "::MAX);")]
2216        /// ```
2217        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2218        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2219        #[must_use = "this returns the result of the operation, \
2220                      without modifying the original"]
2221        #[inline]
2222        pub const fn saturating_sub_signed(self, rhs: $SignedT) -> Self {
2223            let (res, overflow) = self.overflowing_sub_signed(rhs);
2224
2225            if !overflow {
2226                res
2227            } else if rhs < 0 {
2228                Self::MAX
2229            } else {
2230                0
2231            }
2232        }
2233
2234        /// Saturating integer multiplication. Computes `self * rhs`,
2235        /// saturating at the numeric bounds instead of overflowing.
2236        ///
2237        /// # Examples
2238        ///
2239        /// ```
2240        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")]
2241        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")]
2242        /// ```
2243        #[stable(feature = "wrapping", since = "1.7.0")]
2244        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2245        #[must_use = "this returns the result of the operation, \
2246                      without modifying the original"]
2247        #[inline]
2248        pub const fn saturating_mul(self, rhs: Self) -> Self {
2249            match self.checked_mul(rhs) {
2250                Some(x) => x,
2251                None => Self::MAX,
2252            }
2253        }
2254
2255        /// Saturating integer division. Computes `self / rhs`, saturating at the
2256        /// numeric bounds instead of overflowing.
2257        ///
2258        /// # Panics
2259        ///
2260        /// This function will panic if `rhs` is zero.
2261        ///
2262        /// # Examples
2263        ///
2264        /// ```
2265        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2266        ///
2267        /// ```
2268        #[stable(feature = "saturating_div", since = "1.58.0")]
2269        #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2270        #[must_use = "this returns the result of the operation, \
2271                      without modifying the original"]
2272        #[inline]
2273        #[track_caller]
2274        pub const fn saturating_div(self, rhs: Self) -> Self {
2275            // on unsigned types, there is no overflow in integer division
2276            self.wrapping_div(rhs)
2277        }
2278
2279        /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2280        /// saturating at the numeric bounds instead of overflowing.
2281        ///
2282        /// # Examples
2283        ///
2284        /// ```
2285        #[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
2286        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
2287        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2288        /// ```
2289        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2290        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2291        #[must_use = "this returns the result of the operation, \
2292                      without modifying the original"]
2293        #[inline]
2294        pub const fn saturating_pow(self, exp: u32) -> Self {
2295            match self.checked_pow(exp) {
2296                Some(x) => x,
2297                None => Self::MAX,
2298            }
2299        }
2300
2301        /// Wrapping (modular) addition. Computes `self + rhs`,
2302        /// wrapping around at the boundary of the type.
2303        ///
2304        /// # Examples
2305        ///
2306        /// ```
2307        #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")]
2308        #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")]
2309        /// ```
2310        #[stable(feature = "rust1", since = "1.0.0")]
2311        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2312        #[must_use = "this returns the result of the operation, \
2313                      without modifying the original"]
2314        #[inline(always)]
2315        pub const fn wrapping_add(self, rhs: Self) -> Self {
2316            intrinsics::wrapping_add(self, rhs)
2317        }
2318
2319        /// Wrapping (modular) addition with a signed integer. Computes
2320        /// `self + rhs`, wrapping around at the boundary of the type.
2321        ///
2322        /// # Examples
2323        ///
2324        /// ```
2325        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
2326        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
2327        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
2328        /// ```
2329        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2330        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2331        #[must_use = "this returns the result of the operation, \
2332                      without modifying the original"]
2333        #[inline]
2334        pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
2335            self.wrapping_add(rhs as Self)
2336        }
2337
2338        /// Wrapping (modular) subtraction. Computes `self - rhs`,
2339        /// wrapping around at the boundary of the type.
2340        ///
2341        /// # Examples
2342        ///
2343        /// ```
2344        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")]
2345        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")]
2346        /// ```
2347        #[stable(feature = "rust1", since = "1.0.0")]
2348        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2349        #[must_use = "this returns the result of the operation, \
2350                      without modifying the original"]
2351        #[inline(always)]
2352        pub const fn wrapping_sub(self, rhs: Self) -> Self {
2353            intrinsics::wrapping_sub(self, rhs)
2354        }
2355
2356        /// Wrapping (modular) subtraction with a signed integer. Computes
2357        /// `self - rhs`, wrapping around at the boundary of the type.
2358        ///
2359        /// # Examples
2360        ///
2361        /// ```
2362        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(2), ", stringify!($SelfT), "::MAX);")]
2363        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(-2), 3);")]
2364        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_sub_signed(-4), 1);")]
2365        /// ```
2366        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2367        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2368        #[must_use = "this returns the result of the operation, \
2369                      without modifying the original"]
2370        #[inline]
2371        pub const fn wrapping_sub_signed(self, rhs: $SignedT) -> Self {
2372            self.wrapping_sub(rhs as Self)
2373        }
2374
2375        /// Wrapping (modular) multiplication. Computes `self *
2376        /// rhs`, wrapping around at the boundary of the type.
2377        ///
2378        /// # Examples
2379        ///
2380        /// Please note that this example is shared among integer types, which is why `u8` is used.
2381        ///
2382        /// ```
2383        /// assert_eq!(10u8.wrapping_mul(12), 120);
2384        /// assert_eq!(25u8.wrapping_mul(12), 44);
2385        /// ```
2386        #[stable(feature = "rust1", since = "1.0.0")]
2387        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2388        #[must_use = "this returns the result of the operation, \
2389                      without modifying the original"]
2390        #[inline(always)]
2391        pub const fn wrapping_mul(self, rhs: Self) -> Self {
2392            intrinsics::wrapping_mul(self, rhs)
2393        }
2394
2395        /// Wrapping (modular) division. Computes `self / rhs`.
2396        ///
2397        /// Wrapped division on unsigned types is just normal division. There's
2398        /// no way wrapping could ever happen. This function exists so that all
2399        /// operations are accounted for in the wrapping operations.
2400        ///
2401        /// # Panics
2402        ///
2403        /// This function will panic if `rhs` is zero.
2404        ///
2405        /// # Examples
2406        ///
2407        /// ```
2408        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2409        /// ```
2410        #[stable(feature = "num_wrapping", since = "1.2.0")]
2411        #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2412        #[must_use = "this returns the result of the operation, \
2413                      without modifying the original"]
2414        #[inline(always)]
2415        #[track_caller]
2416        pub const fn wrapping_div(self, rhs: Self) -> Self {
2417            self / rhs
2418        }
2419
2420        /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`.
2421        ///
2422        /// Wrapped division on unsigned types is just normal division. There's
2423        /// no way wrapping could ever happen. This function exists so that all
2424        /// operations are accounted for in the wrapping operations. Since, for
2425        /// the positive integers, all common definitions of division are equal,
2426        /// this is exactly equal to `self.wrapping_div(rhs)`.
2427        ///
2428        /// # Panics
2429        ///
2430        /// This function will panic if `rhs` is zero.
2431        ///
2432        /// # Examples
2433        ///
2434        /// ```
2435        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2436        /// ```
2437        #[stable(feature = "euclidean_division", since = "1.38.0")]
2438        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2439        #[must_use = "this returns the result of the operation, \
2440                      without modifying the original"]
2441        #[inline(always)]
2442        #[track_caller]
2443        pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2444            self / rhs
2445        }
2446
2447        /// Wrapping (modular) remainder. Computes `self % rhs`.
2448        ///
2449        /// Wrapped remainder calculation on unsigned types is just the regular
2450        /// remainder calculation. There's no way wrapping could ever happen.
2451        /// This function exists so that all operations are accounted for in the
2452        /// wrapping operations.
2453        ///
2454        /// # Panics
2455        ///
2456        /// This function will panic if `rhs` is zero.
2457        ///
2458        /// # Examples
2459        ///
2460        /// ```
2461        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2462        /// ```
2463        #[stable(feature = "num_wrapping", since = "1.2.0")]
2464        #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2465        #[must_use = "this returns the result of the operation, \
2466                      without modifying the original"]
2467        #[inline(always)]
2468        #[track_caller]
2469        pub const fn wrapping_rem(self, rhs: Self) -> Self {
2470            self % rhs
2471        }
2472
2473        /// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`.
2474        ///
2475        /// Wrapped modulo calculation on unsigned types is just the regular
2476        /// remainder calculation. There's no way wrapping could ever happen.
2477        /// This function exists so that all operations are accounted for in the
2478        /// wrapping operations. Since, for the positive integers, all common
2479        /// definitions of division are equal, this is exactly equal to
2480        /// `self.wrapping_rem(rhs)`.
2481        ///
2482        /// # Panics
2483        ///
2484        /// This function will panic if `rhs` is zero.
2485        ///
2486        /// # Examples
2487        ///
2488        /// ```
2489        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2490        /// ```
2491        #[stable(feature = "euclidean_division", since = "1.38.0")]
2492        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2493        #[must_use = "this returns the result of the operation, \
2494                      without modifying the original"]
2495        #[inline(always)]
2496        #[track_caller]
2497        pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2498            self % rhs
2499        }
2500
2501        /// Wrapping (modular) negation. Computes `-self`,
2502        /// wrapping around at the boundary of the type.
2503        ///
2504        /// Since unsigned types do not have negative equivalents
2505        /// all applications of this function will wrap (except for `-0`).
2506        /// For values smaller than the corresponding signed type's maximum
2507        /// the result is the same as casting the corresponding signed value.
2508        /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
2509        /// `MAX` is the corresponding signed type's maximum.
2510        ///
2511        /// # Examples
2512        ///
2513        /// ```
2514        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
2515        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
2516        #[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
2517        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
2518        /// ```
2519        #[stable(feature = "num_wrapping", since = "1.2.0")]
2520        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2521        #[must_use = "this returns the result of the operation, \
2522                      without modifying the original"]
2523        #[inline(always)]
2524        pub const fn wrapping_neg(self) -> Self {
2525            (0 as $SelfT).wrapping_sub(self)
2526        }
2527
2528        /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
2529        /// where `mask` removes any high-order bits of `rhs` that
2530        /// would cause the shift to exceed the bitwidth of the type.
2531        ///
2532        /// Note that this is *not* the same as a rotate-left; the
2533        /// RHS of a wrapping shift-left is restricted to the range
2534        /// of the type, rather than the bits shifted out of the LHS
2535        /// being returned to the other end. The primitive integer
2536        /// types all implement a [`rotate_left`](Self::rotate_left) function,
2537        /// which may be what you want instead.
2538        ///
2539        /// # Examples
2540        ///
2541        /// ```
2542        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128);")]
2543        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);")]
2544        /// ```
2545        #[stable(feature = "num_wrapping", since = "1.2.0")]
2546        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2547        #[must_use = "this returns the result of the operation, \
2548                      without modifying the original"]
2549        #[inline(always)]
2550        pub const fn wrapping_shl(self, rhs: u32) -> Self {
2551            // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2552            // out of bounds
2553            unsafe {
2554                self.unchecked_shl(rhs & (Self::BITS - 1))
2555            }
2556        }
2557
2558        /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
2559        /// where `mask` removes any high-order bits of `rhs` that
2560        /// would cause the shift to exceed the bitwidth of the type.
2561        ///
2562        /// Note that this is *not* the same as a rotate-right; the
2563        /// RHS of a wrapping shift-right is restricted to the range
2564        /// of the type, rather than the bits shifted out of the LHS
2565        /// being returned to the other end. The primitive integer
2566        /// types all implement a [`rotate_right`](Self::rotate_right) function,
2567        /// which may be what you want instead.
2568        ///
2569        /// # Examples
2570        ///
2571        /// ```
2572        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1);")]
2573        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);")]
2574        /// ```
2575        #[stable(feature = "num_wrapping", since = "1.2.0")]
2576        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2577        #[must_use = "this returns the result of the operation, \
2578                      without modifying the original"]
2579        #[inline(always)]
2580        pub const fn wrapping_shr(self, rhs: u32) -> Self {
2581            // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2582            // out of bounds
2583            unsafe {
2584                self.unchecked_shr(rhs & (Self::BITS - 1))
2585            }
2586        }
2587
2588        /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2589        /// wrapping around at the boundary of the type.
2590        ///
2591        /// # Examples
2592        ///
2593        /// ```
2594        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
2595        /// assert_eq!(3u8.wrapping_pow(6), 217);
2596        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
2597        /// ```
2598        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2599        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2600        #[must_use = "this returns the result of the operation, \
2601                      without modifying the original"]
2602        #[inline]
2603        pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2604            if exp == 0 {
2605                return 1;
2606            }
2607            let mut base = self;
2608            let mut acc: Self = 1;
2609
2610            if intrinsics::is_val_statically_known(exp) {
2611                while exp > 1 {
2612                    if (exp & 1) == 1 {
2613                        acc = acc.wrapping_mul(base);
2614                    }
2615                    exp /= 2;
2616                    base = base.wrapping_mul(base);
2617                }
2618
2619                // since exp!=0, finally the exp must be 1.
2620                // Deal with the final bit of the exponent separately, since
2621                // squaring the base afterwards is not necessary.
2622                acc.wrapping_mul(base)
2623            } else {
2624                // This is faster than the above when the exponent is not known
2625                // at compile time. We can't use the same code for the constant
2626                // exponent case because LLVM is currently unable to unroll
2627                // this loop.
2628                loop {
2629                    if (exp & 1) == 1 {
2630                        acc = acc.wrapping_mul(base);
2631                        // since exp!=0, finally the exp must be 1.
2632                        if exp == 1 {
2633                            return acc;
2634                        }
2635                    }
2636                    exp /= 2;
2637                    base = base.wrapping_mul(base);
2638                }
2639            }
2640        }
2641
2642        /// Calculates `self` + `rhs`.
2643        ///
2644        /// Returns a tuple of the addition along with a boolean indicating
2645        /// whether an arithmetic overflow would occur. If an overflow would
2646        /// have occurred then the wrapped value is returned.
2647        ///
2648        /// # Examples
2649        ///
2650        /// ```
2651        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2652        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")]
2653        /// ```
2654        #[stable(feature = "wrapping", since = "1.7.0")]
2655        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2656        #[must_use = "this returns the result of the operation, \
2657                      without modifying the original"]
2658        #[inline(always)]
2659        pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2660            let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2661            (a as Self, b)
2662        }
2663
2664        /// Calculates `self` + `rhs` + `carry` and returns a tuple containing
2665        /// the sum and the output carry (in that order).
2666        ///
2667        /// Performs "ternary addition" of two integer operands and a carry-in
2668        /// bit, and returns an output integer and a carry-out bit. This allows
2669        /// chaining together multiple additions to create a wider addition, and
2670        /// can be useful for bignum addition.
2671        ///
2672        #[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
2673        ///
2674        /// If the input carry is false, this method is equivalent to
2675        /// [`overflowing_add`](Self::overflowing_add), and the output carry is
2676        /// equal to the overflow flag. Note that although carry and overflow
2677        /// flags are similar for unsigned integers, they are different for
2678        /// signed integers.
2679        ///
2680        /// # Examples
2681        ///
2682        /// ```
2683        #[doc = concat!("//    3  MAX    (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2684        #[doc = concat!("// +  5    7    (b = 5 × 2^", stringify!($BITS), " + 7)")]
2685        /// // ---------
2686        #[doc = concat!("//    9    6    (sum = 9 × 2^", stringify!($BITS), " + 6)")]
2687        ///
2688        #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")]
2689        #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2690        /// let carry0 = false;
2691        ///
2692        /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2693        /// assert_eq!(carry1, true);
2694        /// let (sum1, carry2) = a1.carrying_add(b1, carry1);
2695        /// assert_eq!(carry2, false);
2696        ///
2697        /// assert_eq!((sum1, sum0), (9, 6));
2698        /// ```
2699        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
2700        #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2701        #[must_use = "this returns the result of the operation, \
2702                      without modifying the original"]
2703        #[inline]
2704        pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2705            // note: longer-term this should be done via an intrinsic, but this has been shown
2706            //   to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2707            let (a, c1) = self.overflowing_add(rhs);
2708            let (b, c2) = a.overflowing_add(carry as $SelfT);
2709            // Ideally LLVM would know this is disjoint without us telling them,
2710            // but it doesn't <https://github.com/llvm/llvm-project/issues/118162>
2711            // SAFETY: Only one of `c1` and `c2` can be set.
2712            // For c1 to be set we need to have overflowed, but if we did then
2713            // `a` is at most `MAX-1`, which means that `c2` cannot possibly
2714            // overflow because it's adding at most `1` (since it came from `bool`)
2715            (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2716        }
2717
2718        /// Calculates `self` + `rhs` with a signed `rhs`.
2719        ///
2720        /// Returns a tuple of the addition along with a boolean indicating
2721        /// whether an arithmetic overflow would occur. If an overflow would
2722        /// have occurred then the wrapped value is returned.
2723        ///
2724        /// # Examples
2725        ///
2726        /// ```
2727        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
2728        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
2729        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
2730        /// ```
2731        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2732        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2733        #[must_use = "this returns the result of the operation, \
2734                      without modifying the original"]
2735        #[inline]
2736        pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
2737            let (res, overflowed) = self.overflowing_add(rhs as Self);
2738            (res, overflowed ^ (rhs < 0))
2739        }
2740
2741        /// Calculates `self` - `rhs`.
2742        ///
2743        /// Returns a tuple of the subtraction along with a boolean indicating
2744        /// whether an arithmetic overflow would occur. If an overflow would
2745        /// have occurred then the wrapped value is returned.
2746        ///
2747        /// # Examples
2748        ///
2749        /// ```
2750        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2751        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2752        /// ```
2753        #[stable(feature = "wrapping", since = "1.7.0")]
2754        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2755        #[must_use = "this returns the result of the operation, \
2756                      without modifying the original"]
2757        #[inline(always)]
2758        pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2759            let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2760            (a as Self, b)
2761        }
2762
2763        /// Calculates `self` &minus; `rhs` &minus; `borrow` and returns a tuple
2764        /// containing the difference and the output borrow.
2765        ///
2766        /// Performs "ternary subtraction" by subtracting both an integer
2767        /// operand and a borrow-in bit from `self`, and returns an output
2768        /// integer and a borrow-out bit. This allows chaining together multiple
2769        /// subtractions to create a wider subtraction, and can be useful for
2770        /// bignum subtraction.
2771        ///
2772        /// # Examples
2773        ///
2774        /// ```
2775        #[doc = concat!("//    9    6    (a = 9 × 2^", stringify!($BITS), " + 6)")]
2776        #[doc = concat!("// -  5    7    (b = 5 × 2^", stringify!($BITS), " + 7)")]
2777        /// // ---------
2778        #[doc = concat!("//    3  MAX    (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2779        ///
2780        #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")]
2781        #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2782        /// let borrow0 = false;
2783        ///
2784        /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2785        /// assert_eq!(borrow1, true);
2786        /// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1);
2787        /// assert_eq!(borrow2, false);
2788        ///
2789        #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
2790        /// ```
2791        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
2792        #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2793        #[must_use = "this returns the result of the operation, \
2794                      without modifying the original"]
2795        #[inline]
2796        pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2797            // note: longer-term this should be done via an intrinsic, but this has been shown
2798            //   to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2799            let (a, c1) = self.overflowing_sub(rhs);
2800            let (b, c2) = a.overflowing_sub(borrow as $SelfT);
2801            // SAFETY: Only one of `c1` and `c2` can be set.
2802            // For c1 to be set we need to have underflowed, but if we did then
2803            // `a` is nonzero, which means that `c2` cannot possibly
2804            // underflow because it's subtracting at most `1` (since it came from `bool`)
2805            (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2806        }
2807
2808        /// Calculates `self` - `rhs` with a signed `rhs`
2809        ///
2810        /// Returns a tuple of the subtraction along with a boolean indicating
2811        /// whether an arithmetic overflow would occur. If an overflow would
2812        /// have occurred then the wrapped value is returned.
2813        ///
2814        /// # Examples
2815        ///
2816        /// ```
2817        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(2), (", stringify!($SelfT), "::MAX, true));")]
2818        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(-2), (3, false));")]
2819        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_sub_signed(-4), (1, true));")]
2820        /// ```
2821        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2822        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2823        #[must_use = "this returns the result of the operation, \
2824                      without modifying the original"]
2825        #[inline]
2826        pub const fn overflowing_sub_signed(self, rhs: $SignedT) -> (Self, bool) {
2827            let (res, overflow) = self.overflowing_sub(rhs as Self);
2828
2829            (res, overflow ^ (rhs < 0))
2830        }
2831
2832        /// Computes the absolute difference between `self` and `other`.
2833        ///
2834        /// # Examples
2835        ///
2836        /// ```
2837        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")]
2838        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")]
2839        /// ```
2840        #[stable(feature = "int_abs_diff", since = "1.60.0")]
2841        #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
2842        #[must_use = "this returns the result of the operation, \
2843                      without modifying the original"]
2844        #[inline]
2845        pub const fn abs_diff(self, other: Self) -> Self {
2846            if size_of::<Self>() == 1 {
2847                // Trick LLVM into generating the psadbw instruction when SSE2
2848                // is available and this function is autovectorized for u8's.
2849                (self as i32).wrapping_sub(other as i32).unsigned_abs() as Self
2850            } else {
2851                if self < other {
2852                    other - self
2853                } else {
2854                    self - other
2855                }
2856            }
2857        }
2858
2859        /// Calculates the multiplication of `self` and `rhs`.
2860        ///
2861        /// Returns a tuple of the multiplication along with a boolean
2862        /// indicating whether an arithmetic overflow would occur. If an
2863        /// overflow would have occurred then the wrapped value is returned.
2864        ///
2865        /// If you want the *value* of the overflow, rather than just *whether*
2866        /// an overflow occurred, see [`Self::carrying_mul`].
2867        ///
2868        /// # Examples
2869        ///
2870        /// Please note that this example is shared among integer types, which is why `u32` is used.
2871        ///
2872        /// ```
2873        /// assert_eq!(5u32.overflowing_mul(2), (10, false));
2874        /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
2875        /// ```
2876        #[stable(feature = "wrapping", since = "1.7.0")]
2877        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2878        #[must_use = "this returns the result of the operation, \
2879                          without modifying the original"]
2880        #[inline(always)]
2881        pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2882            let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
2883            (a as Self, b)
2884        }
2885
2886        /// Calculates the complete double-width product `self * rhs`.
2887        ///
2888        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2889        /// of the result as two separate values, in that order. As such,
2890        /// `a.widening_mul(b).0` produces the same result as `a.wrapping_mul(b)`.
2891        ///
2892        /// If you also need to add a value and carry to the wide result, then you want
2893        /// [`Self::carrying_mul_add`] instead.
2894        ///
2895        /// If you also need to add a carry to the wide result, then you want
2896        /// [`Self::carrying_mul`] instead.
2897        ///
2898        /// If you just want to know *whether* the multiplication overflowed, then you
2899        /// want [`Self::overflowing_mul`] instead.
2900        ///
2901        /// # Examples
2902        ///
2903        /// ```
2904        /// #![feature(bigint_helper_methods)]
2905        #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".widening_mul(7), (35, 0));")]
2906        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.widening_mul(", stringify!($SelfT), "::MAX), (1, ", stringify!($SelfT), "::MAX - 1));")]
2907        /// ```
2908        ///
2909        /// Compared to other `*_mul` methods:
2910        /// ```
2911        /// #![feature(bigint_helper_methods)]
2912        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::widening_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, 3));")]
2913        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::overflowing_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, true));")]
2914        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::wrapping_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), 0);")]
2915        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::checked_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), None);")]
2916        /// ```
2917        ///
2918        /// Please note that this example is shared among integer types, which is why `u32` is used.
2919        ///
2920        /// ```
2921        /// #![feature(bigint_helper_methods)]
2922        /// assert_eq!(5u32.widening_mul(2), (10, 0));
2923        /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
2924        /// ```
2925        #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2926        #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2927        #[must_use = "this returns the result of the operation, \
2928                      without modifying the original"]
2929        #[inline]
2930        pub const fn widening_mul(self, rhs: Self) -> (Self, Self) {
2931            Self::carrying_mul_add(self, rhs, 0, 0)
2932        }
2933
2934        /// Calculates the "full multiplication" `self * rhs + carry`
2935        /// without the possibility to overflow.
2936        ///
2937        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2938        /// of the result as two separate values, in that order.
2939        ///
2940        /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2941        /// additional amount of overflow. This allows for chaining together multiple
2942        /// multiplications to create "big integers" which represent larger values.
2943        ///
2944        /// If you also need to add a value, then use [`Self::carrying_mul_add`].
2945        ///
2946        /// # Examples
2947        ///
2948        /// Please note that this example is shared among integer types, which is why `u32` is used.
2949        ///
2950        /// ```
2951        /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
2952        /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
2953        /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
2954        /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
2955        #[doc = concat!("assert_eq!(",
2956            stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2957            "(0, ", stringify!($SelfT), "::MAX));"
2958        )]
2959        /// ```
2960        ///
2961        /// This is the core operation needed for scalar multiplication when
2962        /// implementing it for wider-than-native types.
2963        ///
2964        /// ```
2965        /// #![feature(bigint_helper_methods)]
2966        /// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) {
2967        ///     let mut carry = 0;
2968        ///     for d in little_endian_digits.iter_mut() {
2969        ///         (*d, carry) = d.carrying_mul(multiplicand, carry);
2970        ///     }
2971        ///     if carry != 0 {
2972        ///         little_endian_digits.push(carry);
2973        ///     }
2974        /// }
2975        ///
2976        /// let mut v = vec![10, 20];
2977        /// scalar_mul_eq(&mut v, 3);
2978        /// assert_eq!(v, [30, 60]);
2979        ///
2980        /// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D);
2981        /// let mut v = vec![0x4321, 0x8765];
2982        /// scalar_mul_eq(&mut v, 0xFEED);
2983        /// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]);
2984        /// ```
2985        ///
2986        /// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul),
2987        /// except that it gives the value of the overflow instead of just whether one happened:
2988        ///
2989        /// ```
2990        /// #![feature(bigint_helper_methods)]
2991        /// let r = u8::carrying_mul(7, 13, 0);
2992        /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(7, 13));
2993        /// let r = u8::carrying_mul(13, 42, 0);
2994        /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(13, 42));
2995        /// ```
2996        ///
2997        /// The value of the first field in the returned tuple matches what you'd get
2998        /// by combining the [`wrapping_mul`](Self::wrapping_mul) and
2999        /// [`wrapping_add`](Self::wrapping_add) methods:
3000        ///
3001        /// ```
3002        /// #![feature(bigint_helper_methods)]
3003        /// assert_eq!(
3004        ///     789_u16.carrying_mul(456, 123).0,
3005        ///     789_u16.wrapping_mul(456).wrapping_add(123),
3006        /// );
3007        /// ```
3008        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3009        #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
3010        #[must_use = "this returns the result of the operation, \
3011                      without modifying the original"]
3012        #[inline]
3013        pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
3014            Self::carrying_mul_add(self, rhs, carry, 0)
3015        }
3016
3017        /// Calculates the "full multiplication" `self * rhs + carry + add`.
3018        ///
3019        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3020        /// of the result as two separate values, in that order.
3021        ///
3022        /// This cannot overflow, as the double-width result has exactly enough
3023        /// space for the largest possible result. This is equivalent to how, in
3024        /// decimal, 9 × 9 + 9 + 9 = 81 + 18 = 99 = 9×10⁰ + 9×10¹ = 10² - 1.
3025        ///
3026        /// Performs "long multiplication" which takes in an extra amount to add, and may return an
3027        /// additional amount of overflow. This allows for chaining together multiple
3028        /// multiplications to create "big integers" which represent larger values.
3029        ///
3030        /// If you don't need the `add` part, then you can use [`Self::carrying_mul`] instead.
3031        ///
3032        /// # Examples
3033        ///
3034        /// Please note that this example is shared between integer types,
3035        /// which explains why `u32` is used here.
3036        ///
3037        /// ```
3038        /// assert_eq!(5u32.carrying_mul_add(2, 0, 0), (10, 0));
3039        /// assert_eq!(5u32.carrying_mul_add(2, 10, 10), (30, 0));
3040        /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 0, 0), (1410065408, 2));
3041        /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 10, 10), (1410065428, 2));
3042        #[doc = concat!("assert_eq!(",
3043            stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
3044            "(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX));"
3045        )]
3046        /// ```
3047        ///
3048        /// This is the core per-digit operation for "grade school" O(n²) multiplication.
3049        ///
3050        /// Please note that this example is shared between integer types,
3051        /// using `u8` for simplicity of the demonstration.
3052        ///
3053        /// ```
3054        /// fn quadratic_mul<const N: usize>(a: [u8; N], b: [u8; N]) -> [u8; N] {
3055        ///     let mut out = [0; N];
3056        ///     for j in 0..N {
3057        ///         let mut carry = 0;
3058        ///         for i in 0..(N - j) {
3059        ///             (out[j + i], carry) = u8::carrying_mul_add(a[i], b[j], out[j + i], carry);
3060        ///         }
3061        ///     }
3062        ///     out
3063        /// }
3064        ///
3065        /// // -1 * -1 == 1
3066        /// assert_eq!(quadratic_mul([0xFF; 3], [0xFF; 3]), [1, 0, 0]);
3067        ///
3068        /// assert_eq!(u32::wrapping_mul(0x9e3779b9, 0x7f4a7c15), 0xcffc982d);
3069        /// assert_eq!(
3070        ///     quadratic_mul(u32::to_le_bytes(0x9e3779b9), u32::to_le_bytes(0x7f4a7c15)),
3071        ///     u32::to_le_bytes(0xcffc982d)
3072        /// );
3073        /// ```
3074        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3075        #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
3076        #[must_use = "this returns the result of the operation, \
3077                      without modifying the original"]
3078        #[inline]
3079        pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> (Self, Self) {
3080            intrinsics::carrying_mul_add(self, rhs, carry, add)
3081        }
3082
3083        /// Calculates the divisor when `self` is divided by `rhs`.
3084        ///
3085        /// Returns a tuple of the divisor along with a boolean indicating
3086        /// whether an arithmetic overflow would occur. Note that for unsigned
3087        /// integers overflow never occurs, so the second value is always
3088        /// `false`.
3089        ///
3090        /// # Panics
3091        ///
3092        /// This function will panic if `rhs` is zero.
3093        ///
3094        /// # Examples
3095        ///
3096        /// ```
3097        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
3098        /// ```
3099        #[inline(always)]
3100        #[stable(feature = "wrapping", since = "1.7.0")]
3101        #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
3102        #[must_use = "this returns the result of the operation, \
3103                      without modifying the original"]
3104        #[track_caller]
3105        pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
3106            (self / rhs, false)
3107        }
3108
3109        /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
3110        ///
3111        /// Returns a tuple of the divisor along with a boolean indicating
3112        /// whether an arithmetic overflow would occur. Note that for unsigned
3113        /// integers overflow never occurs, so the second value is always
3114        /// `false`.
3115        /// Since, for the positive integers, all common
3116        /// definitions of division are equal, this
3117        /// is exactly equal to `self.overflowing_div(rhs)`.
3118        ///
3119        /// # Panics
3120        ///
3121        /// This function will panic if `rhs` is zero.
3122        ///
3123        /// # Examples
3124        ///
3125        /// ```
3126        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
3127        /// ```
3128        #[inline(always)]
3129        #[stable(feature = "euclidean_division", since = "1.38.0")]
3130        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3131        #[must_use = "this returns the result of the operation, \
3132                      without modifying the original"]
3133        #[track_caller]
3134        pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
3135            (self / rhs, false)
3136        }
3137
3138        /// Calculates the remainder when `self` is divided by `rhs`.
3139        ///
3140        /// Returns a tuple of the remainder after dividing along with a boolean
3141        /// indicating whether an arithmetic overflow would occur. Note that for
3142        /// unsigned integers overflow never occurs, so the second value is
3143        /// always `false`.
3144        ///
3145        /// # Panics
3146        ///
3147        /// This function will panic if `rhs` is zero.
3148        ///
3149        /// # Examples
3150        ///
3151        /// ```
3152        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
3153        /// ```
3154        #[inline(always)]
3155        #[stable(feature = "wrapping", since = "1.7.0")]
3156        #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
3157        #[must_use = "this returns the result of the operation, \
3158                      without modifying the original"]
3159        #[track_caller]
3160        pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
3161            (self % rhs, false)
3162        }
3163
3164        /// Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division.
3165        ///
3166        /// Returns a tuple of the modulo after dividing along with a boolean
3167        /// indicating whether an arithmetic overflow would occur. Note that for
3168        /// unsigned integers overflow never occurs, so the second value is
3169        /// always `false`.
3170        /// Since, for the positive integers, all common
3171        /// definitions of division are equal, this operation
3172        /// is exactly equal to `self.overflowing_rem(rhs)`.
3173        ///
3174        /// # Panics
3175        ///
3176        /// This function will panic if `rhs` is zero.
3177        ///
3178        /// # Examples
3179        ///
3180        /// ```
3181        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
3182        /// ```
3183        #[inline(always)]
3184        #[stable(feature = "euclidean_division", since = "1.38.0")]
3185        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3186        #[must_use = "this returns the result of the operation, \
3187                      without modifying the original"]
3188        #[track_caller]
3189        pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
3190            (self % rhs, false)
3191        }
3192
3193        /// Negates self in an overflowing fashion.
3194        ///
3195        /// Returns `!self + 1` using wrapping operations to return the value
3196        /// that represents the negation of this unsigned value. Note that for
3197        /// positive unsigned values overflow always occurs, but negating 0 does
3198        /// not overflow.
3199        ///
3200        /// # Examples
3201        ///
3202        /// ```
3203        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")]
3204        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")]
3205        /// ```
3206        #[inline(always)]
3207        #[stable(feature = "wrapping", since = "1.7.0")]
3208        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3209        #[must_use = "this returns the result of the operation, \
3210                      without modifying the original"]
3211        pub const fn overflowing_neg(self) -> (Self, bool) {
3212            ((!self).wrapping_add(1), self != 0)
3213        }
3214
3215        /// Shifts self left by `rhs` bits.
3216        ///
3217        /// Returns a tuple of the shifted version of self along with a boolean
3218        /// indicating whether the shift value was larger than or equal to the
3219        /// number of bits. If the shift value is too large, then value is
3220        /// masked (N-1) where N is the number of bits, and this value is then
3221        /// used to perform the shift.
3222        ///
3223        /// # Examples
3224        ///
3225        /// ```
3226        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
3227        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")]
3228        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
3229        /// ```
3230        #[stable(feature = "wrapping", since = "1.7.0")]
3231        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3232        #[must_use = "this returns the result of the operation, \
3233                      without modifying the original"]
3234        #[inline(always)]
3235        pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
3236            (self.wrapping_shl(rhs), rhs >= Self::BITS)
3237        }
3238
3239        /// Shifts self right by `rhs` bits.
3240        ///
3241        /// Returns a tuple of the shifted version of self along with a boolean
3242        /// indicating whether the shift value was larger than or equal to the
3243        /// number of bits. If the shift value is too large, then value is
3244        /// masked (N-1) where N is the number of bits, and this value is then
3245        /// used to perform the shift.
3246        ///
3247        /// # Examples
3248        ///
3249        /// ```
3250        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
3251        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
3252        /// ```
3253        #[stable(feature = "wrapping", since = "1.7.0")]
3254        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3255        #[must_use = "this returns the result of the operation, \
3256                      without modifying the original"]
3257        #[inline(always)]
3258        pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
3259            (self.wrapping_shr(rhs), rhs >= Self::BITS)
3260        }
3261
3262        /// Raises self to the power of `exp`, using exponentiation by squaring.
3263        ///
3264        /// Returns a tuple of the exponentiation along with a bool indicating
3265        /// whether an overflow happened.
3266        ///
3267        /// # Examples
3268        ///
3269        /// ```
3270        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
3271        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
3272        /// assert_eq!(3u8.overflowing_pow(6), (217, true));
3273        /// ```
3274        #[stable(feature = "no_panic_pow", since = "1.34.0")]
3275        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3276        #[must_use = "this returns the result of the operation, \
3277                      without modifying the original"]
3278        #[inline]
3279        pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3280            if exp == 0{
3281                return (1,false);
3282            }
3283            let mut base = self;
3284            let mut acc: Self = 1;
3285            let mut overflown = false;
3286            // Scratch space for storing results of overflowing_mul.
3287            let mut r;
3288
3289            loop {
3290                if (exp & 1) == 1 {
3291                    r = acc.overflowing_mul(base);
3292                    // since exp!=0, finally the exp must be 1.
3293                    if exp == 1 {
3294                        r.1 |= overflown;
3295                        return r;
3296                    }
3297                    acc = r.0;
3298                    overflown |= r.1;
3299                }
3300                exp /= 2;
3301                r = base.overflowing_mul(base);
3302                base = r.0;
3303                overflown |= r.1;
3304            }
3305        }
3306
3307        /// Raises self to the power of `exp`, using exponentiation by squaring.
3308        ///
3309        /// # Examples
3310        ///
3311        /// ```
3312        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
3313        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
3314        /// ```
3315        #[stable(feature = "rust1", since = "1.0.0")]
3316        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3317        #[must_use = "this returns the result of the operation, \
3318                      without modifying the original"]
3319        #[inline]
3320        #[rustc_inherit_overflow_checks]
3321        pub const fn pow(self, mut exp: u32) -> Self {
3322            if exp == 0 {
3323                return 1;
3324            }
3325            let mut base = self;
3326            let mut acc = 1;
3327
3328            if intrinsics::is_val_statically_known(exp) {
3329                while exp > 1 {
3330                    if (exp & 1) == 1 {
3331                        acc = acc * base;
3332                    }
3333                    exp /= 2;
3334                    base = base * base;
3335                }
3336
3337                // since exp!=0, finally the exp must be 1.
3338                // Deal with the final bit of the exponent separately, since
3339                // squaring the base afterwards is not necessary and may cause a
3340                // needless overflow.
3341                acc * base
3342            } else {
3343                // This is faster than the above when the exponent is not known
3344                // at compile time. We can't use the same code for the constant
3345                // exponent case because LLVM is currently unable to unroll
3346                // this loop.
3347                loop {
3348                    if (exp & 1) == 1 {
3349                        acc = acc * base;
3350                        // since exp!=0, finally the exp must be 1.
3351                        if exp == 1 {
3352                            return acc;
3353                        }
3354                    }
3355                    exp /= 2;
3356                    base = base * base;
3357                }
3358            }
3359        }
3360
3361        /// Returns the square root of the number, rounded down.
3362        ///
3363        /// # Examples
3364        ///
3365        /// ```
3366        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3367        /// ```
3368        #[stable(feature = "isqrt", since = "1.84.0")]
3369        #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3370        #[must_use = "this returns the result of the operation, \
3371                      without modifying the original"]
3372        #[inline]
3373        pub const fn isqrt(self) -> Self {
3374            let result = crate::num::int_sqrt::$ActualT(self as $ActualT) as $SelfT;
3375
3376            // Inform the optimizer what the range of outputs is. If testing
3377            // `core` crashes with no panic message and a `num::int_sqrt::u*`
3378            // test failed, it's because your edits caused these assertions or
3379            // the assertions in `fn isqrt` of `nonzero.rs` to become false.
3380            //
3381            // SAFETY: Integer square root is a monotonically nondecreasing
3382            // function, which means that increasing the input will never
3383            // cause the output to decrease. Thus, since the input for unsigned
3384            // integers is bounded by `[0, <$ActualT>::MAX]`, sqrt(n) will be
3385            // bounded by `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
3386            unsafe {
3387                const MAX_RESULT: $SelfT = crate::num::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT;
3388                crate::hint::assert_unchecked(result <= MAX_RESULT);
3389            }
3390
3391            result
3392        }
3393
3394        /// Performs Euclidean division.
3395        ///
3396        /// Since, for the positive integers, all common
3397        /// definitions of division are equal, this
3398        /// is exactly equal to `self / rhs`.
3399        ///
3400        /// # Panics
3401        ///
3402        /// This function will panic if `rhs` is zero.
3403        ///
3404        /// # Examples
3405        ///
3406        /// ```
3407        #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
3408        /// ```
3409        #[stable(feature = "euclidean_division", since = "1.38.0")]
3410        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3411        #[must_use = "this returns the result of the operation, \
3412                      without modifying the original"]
3413        #[inline(always)]
3414        #[track_caller]
3415        pub const fn div_euclid(self, rhs: Self) -> Self {
3416            self / rhs
3417        }
3418
3419
3420        /// Calculates the least remainder of `self (mod rhs)`.
3421        ///
3422        /// Since, for the positive integers, all common
3423        /// definitions of division are equal, this
3424        /// is exactly equal to `self % rhs`.
3425        ///
3426        /// # Panics
3427        ///
3428        /// This function will panic if `rhs` is zero.
3429        ///
3430        /// # Examples
3431        ///
3432        /// ```
3433        #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")]
3434        /// ```
3435        #[doc(alias = "modulo", alias = "mod")]
3436        #[stable(feature = "euclidean_division", since = "1.38.0")]
3437        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3438        #[must_use = "this returns the result of the operation, \
3439                      without modifying the original"]
3440        #[inline(always)]
3441        #[track_caller]
3442        pub const fn rem_euclid(self, rhs: Self) -> Self {
3443            self % rhs
3444        }
3445
3446        /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3447        ///
3448        /// This is the same as performing `self / rhs` for all unsigned integers.
3449        ///
3450        /// # Panics
3451        ///
3452        /// This function will panic if `rhs` is zero.
3453        ///
3454        /// # Examples
3455        ///
3456        /// ```
3457        /// #![feature(int_roundings)]
3458        #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
3459        /// ```
3460        #[unstable(feature = "int_roundings", issue = "88581")]
3461        #[must_use = "this returns the result of the operation, \
3462                      without modifying the original"]
3463        #[inline(always)]
3464        #[track_caller]
3465        pub const fn div_floor(self, rhs: Self) -> Self {
3466            self / rhs
3467        }
3468
3469        /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3470        ///
3471        /// # Panics
3472        ///
3473        /// This function will panic if `rhs` is zero.
3474        ///
3475        /// # Examples
3476        ///
3477        /// ```
3478        #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
3479        /// ```
3480        #[stable(feature = "int_roundings1", since = "1.73.0")]
3481        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3482        #[must_use = "this returns the result of the operation, \
3483                      without modifying the original"]
3484        #[inline]
3485        #[track_caller]
3486        pub const fn div_ceil(self, rhs: Self) -> Self {
3487            let d = self / rhs;
3488            let r = self % rhs;
3489            if r > 0 {
3490                d + 1
3491            } else {
3492                d
3493            }
3494        }
3495
3496        /// Calculates the smallest value greater than or equal to `self` that
3497        /// is a multiple of `rhs`.
3498        ///
3499        /// # Panics
3500        ///
3501        /// This function will panic if `rhs` is zero.
3502        ///
3503        /// ## Overflow behavior
3504        ///
3505        /// On overflow, this function will panic if overflow checks are enabled (default in debug
3506        /// mode) and wrap if overflow checks are disabled (default in release mode).
3507        ///
3508        /// # Examples
3509        ///
3510        /// ```
3511        #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3512        #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3513        /// ```
3514        #[stable(feature = "int_roundings1", since = "1.73.0")]
3515        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3516        #[must_use = "this returns the result of the operation, \
3517                      without modifying the original"]
3518        #[inline]
3519        #[rustc_inherit_overflow_checks]
3520        pub const fn next_multiple_of(self, rhs: Self) -> Self {
3521            match self % rhs {
3522                0 => self,
3523                r => self + (rhs - r)
3524            }
3525        }
3526
3527        /// Calculates the smallest value greater than or equal to `self` that
3528        /// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the
3529        /// operation would result in overflow.
3530        ///
3531        /// # Examples
3532        ///
3533        /// ```
3534        #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3535        #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3536        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3537        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3538        /// ```
3539        #[stable(feature = "int_roundings1", since = "1.73.0")]
3540        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3541        #[must_use = "this returns the result of the operation, \
3542                      without modifying the original"]
3543        #[inline]
3544        pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3545            match try_opt!(self.checked_rem(rhs)) {
3546                0 => Some(self),
3547                // rhs - r cannot overflow because r is smaller than rhs
3548                r => self.checked_add(rhs - r)
3549            }
3550        }
3551
3552        /// Returns `true` if `self` is an integer multiple of `rhs`, and false otherwise.
3553        ///
3554        /// This function is equivalent to `self % rhs == 0`, except that it will not panic
3555        /// for `rhs == 0`. Instead, `0.is_multiple_of(0) == true`, and for any non-zero `n`,
3556        /// `n.is_multiple_of(0) == false`.
3557        ///
3558        /// # Examples
3559        ///
3560        /// ```
3561        #[doc = concat!("assert!(6_", stringify!($SelfT), ".is_multiple_of(2));")]
3562        #[doc = concat!("assert!(!5_", stringify!($SelfT), ".is_multiple_of(2));")]
3563        ///
3564        #[doc = concat!("assert!(0_", stringify!($SelfT), ".is_multiple_of(0));")]
3565        #[doc = concat!("assert!(!6_", stringify!($SelfT), ".is_multiple_of(0));")]
3566        /// ```
3567        #[stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3568        #[rustc_const_stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3569        #[must_use]
3570        #[inline]
3571        pub const fn is_multiple_of(self, rhs: Self) -> bool {
3572            match rhs {
3573                0 => self == 0,
3574                _ => self % rhs == 0,
3575            }
3576        }
3577
3578        /// Returns `true` if and only if `self == 2^k` for some unsigned integer `k`.
3579        ///
3580        /// # Examples
3581        ///
3582        /// ```
3583        #[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")]
3584        #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")]
3585        /// ```
3586        #[must_use]
3587        #[stable(feature = "rust1", since = "1.0.0")]
3588        #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")]
3589        #[inline(always)]
3590        pub const fn is_power_of_two(self) -> bool {
3591            self.count_ones() == 1
3592        }
3593
3594        // Returns one less than next power of two.
3595        // (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8)
3596        //
3597        // 8u8.one_less_than_next_power_of_two() == 7
3598        // 6u8.one_less_than_next_power_of_two() == 7
3599        //
3600        // This method cannot overflow, as in the `next_power_of_two`
3601        // overflow cases it instead ends up returning the maximum value
3602        // of the type, and can return 0 for 0.
3603        #[inline]
3604        const fn one_less_than_next_power_of_two(self) -> Self {
3605            if self <= 1 { return 0; }
3606
3607            let p = self - 1;
3608            // SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros.
3609            // That means the shift is always in-bounds, and some processors
3610            // (such as intel pre-haswell) have more efficient ctlz
3611            // intrinsics when the argument is non-zero.
3612            let z = unsafe { intrinsics::ctlz_nonzero(p) };
3613            <$SelfT>::MAX >> z
3614        }
3615
3616        /// Returns the smallest power of two greater than or equal to `self`.
3617        ///
3618        /// When return value overflows (i.e., `self > (1 << (N-1))` for type
3619        /// `uN`), it panics in debug mode and the return value is wrapped to 0 in
3620        /// release mode (the only situation in which this method can return 0).
3621        ///
3622        /// # Examples
3623        ///
3624        /// ```
3625        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
3626        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
3627        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".next_power_of_two(), 1);")]
3628        /// ```
3629        #[stable(feature = "rust1", since = "1.0.0")]
3630        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3631        #[must_use = "this returns the result of the operation, \
3632                      without modifying the original"]
3633        #[inline]
3634        #[rustc_inherit_overflow_checks]
3635        pub const fn next_power_of_two(self) -> Self {
3636            self.one_less_than_next_power_of_two() + 1
3637        }
3638
3639        /// Returns the smallest power of two greater than or equal to `self`. If
3640        /// the next power of two is greater than the type's maximum value,
3641        /// `None` is returned, otherwise the power of two is wrapped in `Some`.
3642        ///
3643        /// # Examples
3644        ///
3645        /// ```
3646        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")]
3647        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")]
3648        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")]
3649        /// ```
3650        #[inline]
3651        #[stable(feature = "rust1", since = "1.0.0")]
3652        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3653        #[must_use = "this returns the result of the operation, \
3654                      without modifying the original"]
3655        pub const fn checked_next_power_of_two(self) -> Option<Self> {
3656            self.one_less_than_next_power_of_two().checked_add(1)
3657        }
3658
3659        /// Returns the smallest power of two greater than or equal to `n`. If
3660        /// the next power of two is greater than the type's maximum value,
3661        /// the return value is wrapped to `0`.
3662        ///
3663        /// # Examples
3664        ///
3665        /// ```
3666        /// #![feature(wrapping_next_power_of_two)]
3667        ///
3668        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")]
3669        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")]
3670        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")]
3671        /// ```
3672        #[inline]
3673        #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
3674                   reason = "needs decision on wrapping behavior")]
3675        #[must_use = "this returns the result of the operation, \
3676                      without modifying the original"]
3677        pub const fn wrapping_next_power_of_two(self) -> Self {
3678            self.one_less_than_next_power_of_two().wrapping_add(1)
3679        }
3680
3681        /// Returns the memory representation of this integer as a byte array in
3682        /// big-endian (network) byte order.
3683        ///
3684        #[doc = $to_xe_bytes_doc]
3685        ///
3686        /// # Examples
3687        ///
3688        /// ```
3689        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3690        #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3691        /// ```
3692        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3693        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3694        #[must_use = "this returns the result of the operation, \
3695                      without modifying the original"]
3696        #[inline]
3697        pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3698            self.to_be().to_ne_bytes()
3699        }
3700
3701        /// Returns the memory representation of this integer as a byte array in
3702        /// little-endian byte order.
3703        ///
3704        #[doc = $to_xe_bytes_doc]
3705        ///
3706        /// # Examples
3707        ///
3708        /// ```
3709        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3710        #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3711        /// ```
3712        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3713        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3714        #[must_use = "this returns the result of the operation, \
3715                      without modifying the original"]
3716        #[inline]
3717        pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3718            self.to_le().to_ne_bytes()
3719        }
3720
3721        /// Returns the memory representation of this integer as a byte array in
3722        /// native byte order.
3723        ///
3724        /// As the target platform's native endianness is used, portable code
3725        /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3726        /// instead.
3727        ///
3728        #[doc = $to_xe_bytes_doc]
3729        ///
3730        /// [`to_be_bytes`]: Self::to_be_bytes
3731        /// [`to_le_bytes`]: Self::to_le_bytes
3732        ///
3733        /// # Examples
3734        ///
3735        /// ```
3736        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3737        /// assert_eq!(
3738        ///     bytes,
3739        ///     if cfg!(target_endian = "big") {
3740        #[doc = concat!("        ", $be_bytes)]
3741        ///     } else {
3742        #[doc = concat!("        ", $le_bytes)]
3743        ///     }
3744        /// );
3745        /// ```
3746        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3747        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3748        #[must_use = "this returns the result of the operation, \
3749                      without modifying the original"]
3750        #[allow(unnecessary_transmutes)]
3751        // SAFETY: const sound because integers are plain old datatypes so we can always
3752        // transmute them to arrays of bytes
3753        #[inline]
3754        pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3755            // SAFETY: integers are plain old datatypes so we can always transmute them to
3756            // arrays of bytes
3757            unsafe { mem::transmute(self) }
3758        }
3759
3760        /// Creates a native endian integer value from its representation
3761        /// as a byte array in big endian.
3762        ///
3763        #[doc = $from_xe_bytes_doc]
3764        ///
3765        /// # Examples
3766        ///
3767        /// ```
3768        #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3769        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3770        /// ```
3771        ///
3772        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3773        ///
3774        /// ```
3775        #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3776        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3777        ///     *input = rest;
3778        #[doc = concat!("    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3779        /// }
3780        /// ```
3781        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3782        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3783        #[must_use]
3784        #[inline]
3785        pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3786            Self::from_be(Self::from_ne_bytes(bytes))
3787        }
3788
3789        /// Creates a native endian integer value from its representation
3790        /// as a byte array in little endian.
3791        ///
3792        #[doc = $from_xe_bytes_doc]
3793        ///
3794        /// # Examples
3795        ///
3796        /// ```
3797        #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3798        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3799        /// ```
3800        ///
3801        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3802        ///
3803        /// ```
3804        #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3805        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3806        ///     *input = rest;
3807        #[doc = concat!("    ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3808        /// }
3809        /// ```
3810        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3811        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3812        #[must_use]
3813        #[inline]
3814        pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3815            Self::from_le(Self::from_ne_bytes(bytes))
3816        }
3817
3818        /// Creates a native endian integer value from its memory representation
3819        /// as a byte array in native endianness.
3820        ///
3821        /// As the target platform's native endianness is used, portable code
3822        /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3823        /// appropriate instead.
3824        ///
3825        /// [`from_be_bytes`]: Self::from_be_bytes
3826        /// [`from_le_bytes`]: Self::from_le_bytes
3827        ///
3828        #[doc = $from_xe_bytes_doc]
3829        ///
3830        /// # Examples
3831        ///
3832        /// ```
3833        #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
3834        #[doc = concat!("    ", $be_bytes, "")]
3835        /// } else {
3836        #[doc = concat!("    ", $le_bytes, "")]
3837        /// });
3838        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3839        /// ```
3840        ///
3841        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3842        ///
3843        /// ```
3844        #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3845        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3846        ///     *input = rest;
3847        #[doc = concat!("    ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
3848        /// }
3849        /// ```
3850        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3851        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3852        #[allow(unnecessary_transmutes)]
3853        #[must_use]
3854        // SAFETY: const sound because integers are plain old datatypes so we can always
3855        // transmute to them
3856        #[inline]
3857        pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3858            // SAFETY: integers are plain old datatypes so we can always transmute to them
3859            unsafe { mem::transmute(bytes) }
3860        }
3861
3862        /// New code should prefer to use
3863        #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
3864        ///
3865        /// Returns the smallest value that can be represented by this integer type.
3866        #[stable(feature = "rust1", since = "1.0.0")]
3867        #[rustc_promotable]
3868        #[inline(always)]
3869        #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3870        #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
3871        #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
3872        pub const fn min_value() -> Self { Self::MIN }
3873
3874        /// New code should prefer to use
3875        #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
3876        ///
3877        /// Returns the largest value that can be represented by this integer type.
3878        #[stable(feature = "rust1", since = "1.0.0")]
3879        #[rustc_promotable]
3880        #[inline(always)]
3881        #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3882        #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
3883        #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
3884        pub const fn max_value() -> Self { Self::MAX }
3885    }
3886}