The code is changed as it was suggested.

1 files changed, 7 insertions, 22 deletions

diff --git a/src/cpu/arm/cortex-m3/bitband.fth b/src/cpu/arm/cortex-m3/bitband.fth
index e919cf4..2966409 100644
--- a/src/cpu/arm/cortex-m3/bitband.fth
+++ b/src/cpu/arm/cortex-m3/bitband.fth
@@ -10,27 +10,12 @@
 \   0 x !
 \   x 0 BITBAND 1 swap c! x @ .
 
-1 #28 shift 1- constant BITBAND.BASEMASK_               \ covers the offset
-BITBAND.BASEMASK_ invert constant BITBAND.BASEMASK      \ covers only the page
-\ bit_word_offset is the position of the target bit in the bit-band memory region.
-$2000000 constant BITBAND.OFFSET
-
-: BITBAND ( addr bit -- aliasaddress )
-    $4 * \ offest caused by the bit
-    swap
-    dup  \ we need to split the addr is two parts
-	\ get the bit_band_base - the starting address of the alias region.
-    BITBAND.BASEMASK and
-    swap
-	\ get the byte_offset - the number of the byte in the bit-band region that
-	\ contains the targeted bit.
-    BITBAND.BASEMASK_
-    and $20 *
-    + +
-	\ add the bit_word_offset - the position of the target bit in the bit-band
-	\ memory region.
-    BITBAND.OFFSET +
+: bitband  ( bit adr -- aliasadr )
+   dup 5 lshift            ( bit adr byte-offset )  \ Spread low part of address; high bits will be shifted out
+   swap $f000.0000 and or  ( bit adr' )             \ Keep high nibble of address
+   $0200.0000 or           ( bit adr' )             \ Offset to bitband alias space
+   swap la+                ( aliasadr )             \ Merge bit number as 32-bit word offset
 ;
 
-." Test for SFR " $4001140C 5 BITBAND $42228194 = if ." Passed" else ." Failed" then CR
-." Test for RAM " $200FFFFC #24 BITBAND $23ffffe0 = if ." Passed" else ." Failed" then CR
+." Test for SFR "   5 $4001140C BITBAND $42228194 = if ." Passed" else ." Failed" then CR
+." Test for RAM " #24 $200FFFFC BITBAND $23ffffe0 = if ." Passed" else ." Failed" then CR