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Submit FS#11502. Minor optimization to Coldfire assembler in libatrac's fixmul16(). Thanks to Nils Willménius.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27596 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Andree Buschmann 2010-07-28 18:17:56 +00:00
parent 8cc8bb9bde
commit ae37fadb1b
1 changed files with 11 additions and 16 deletions
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27
apps/codecs/libatrac/fixp_math.h
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@ -60,25 +60,20 @@
lo; \
})
#elif defined(CPU_COLDFIRE)
/* Calculates: result = (X*Y)>>16 */
#define fixmul16(X,Y) \
({ \
int32_t t1, t2; \
int32_t t, x = (X); \
asm volatile ( \
"mac.l %[x],%[y],%%acc0\n\t" /* multiply */ \
"mulu.l %[y],%[x] \n\t" /* get lower half, avoid emac stall */ \
"movclr.l %%acc0,%[t1] \n\t" /* get higher half */ \
"moveq.l #15,%[t2] \n\t" \
"asl.l %[t2],%[t1] \n\t" /* hi <<= 15, plus one free */ \
"moveq.l #16,%[t2] \n\t" \
"lsr.l %[t2],%[x] \n\t" /* (unsigned)lo >>= 16 */ \
"or.l %[x],%[t1] \n\t" /* combine result */ \
: /* outputs */ \
[t1]"=&d"(t1), \
[t2]"=&d"(t2) \
: /* inputs */ \
[x] "d" ((X)), \
[y] "d" ((Y))); \
t1; \
"mac.l %[x],%[y],%%acc0\n\t" /* multiply */ \
"mulu.l %[y],%[x] \n\t" /* get lower half, avoid emac stall */ \
"movclr.l %%acc0,%[t] \n\t" /* get higher half */ \
"lsr.l #1,%[t] \n\t" /* hi >>= 1 to compensate emac shift */ \
"move.w %[t],%[x] \n\t" /* combine halfwords */\
"swap %[x] \n\t" \
: [t]"=&d"(t), [x] "+d" (x) \
: [y] "d" ((Y))); \
x; \
})
#define fixmul31(X,Y) \