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diff --git a/man-pages-posix-2003/man3p/fma.3p b/man-pages-posix-2003/man3p/fma.3p new file mode 100644 index 0000000..f7065d9 --- /dev/null +++ b/man-pages-posix-2003/man3p/fma.3p @@ -0,0 +1,141 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "FMA" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" fma +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.SH NAME +fma, fmaf, fmal \- floating-point multiply-add +.SH SYNOPSIS +.LP +\fB#include <math.h> +.br +.sp +double fma(double\fP \fIx\fP\fB, double\fP \fIy\fP\fB, double\fP \fIz\fP\fB); +.br +float fmaf(float\fP \fIx\fP\fB, float\fP \fIy\fP\fB, float\fP \fIz\fP\fB); +.br +long double fmal(long double\fP \fIx\fP\fB, long double\fP \fIy\fP\fB, +long double\fP \fIz\fP\fB); +.br +\fP +.SH DESCRIPTION +.LP +These functions shall compute (\fIx\fP\ *\ \fIy\fP)\ +\ \fIz\fP, rounded +as one ternary operation: they shall +compute the value (as if) to infinite precision and round once to +the result format, according to the rounding mode characterized +by the value of FLT_ROUNDS. +.LP +An application wishing to check for error situations should set \fIerrno\fP +to zero and call +\fIfeclearexcept\fP(FE_ALL_EXCEPT) before calling these functions. +On return, if \fIerrno\fP is non-zero or +\fIfetestexcept\fP(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) +is non-zero, an error has occurred. +.SH RETURN VALUE +.LP +Upon successful completion, these functions shall return (\fIx\fP\ *\ \fIy\fP)\ + +\fIz\fP, rounded as one ternary +operation. +.LP +If +\fIx\fP or \fIy\fP are NaN, a NaN shall be returned. +.LP +If \fIx\fP multiplied by \fIy\fP is an exact infinity and \fIz\fP +is also an infinity but with the opposite sign, a domain +error shall occur, and either a NaN (if supported), or an implementation-defined +value shall be returned. +.LP +If one of \fIx\fP and \fIy\fP is infinite, the other is zero, and +\fIz\fP is not a NaN, a domain error shall occur, and +either a NaN (if supported), or an implementation-defined value shall +be returned. +.LP +If one of \fIx\fP and \fIy\fP is infinite, the other is zero, and +\fIz\fP is a NaN, a NaN shall be returned and a domain +error may occur. +.LP +If \fIx\fP* \fIy\fP is not 0*Inf nor Inf*0 and \fIz\fP is a NaN, a +NaN shall be returned. +.SH ERRORS +.LP +These functions shall fail if: +.TP 7 +Domain\ Error +The value of \fIx\fP* \fIy\fP+ \fIz\fP is invalid, or the value \fIx\fP* +\fIy\fP is invalid and \fIz\fP is not a NaN. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP shall be set to [EDOM]. If the +integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, +then the invalid floating-point exception shall be raised. +.TP 7 +Range\ Error +The result overflows. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP shall be set to [ERANGE]. If the +integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, +then the overflow floating-point exception shall be raised. +.sp +.LP +These functions may fail if: +.TP 7 +Domain\ Error +The value \fIx\fP* \fIy\fP is invalid and \fIz\fP is a NaN. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP shall be set to [EDOM]. If the +integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, +then the invalid floating-point exception shall be raised. +.TP 7 +Range\ Error +The result underflows. +.LP +If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, +then \fIerrno\fP shall be set to [ERANGE]. If the +integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, +then the underflow floating-point exception shall be +raised. +.sp +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling +& MATH_ERREXCEPT) are independent of +each other, but at least one of them must be non-zero. +.SH RATIONALE +.LP +In many cases, clever use of floating (\fIfused\fP) multiply-add leads +to much improved code; but its unexpected use by the +compiler can undermine carefully written code. The FP_CONTRACT macro +can be used to disallow use of floating multiply-add; and the +\fIfma\fP() function guarantees its use where desired. Many current +machines provide hardware floating multiply-add instructions; +software implementation can be used for others. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fIfeclearexcept\fP(), \fIfetestexcept\fP(), the Base +Definitions volume of IEEE\ Std\ 1003.1-2001, Section 4.18, Treatment +of +Error Conditions for Mathematical Functions, \fI<math.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . |