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several x86 renorm_cabac_decoder_once optimizations 

START/STOP_TIMER benchmarking code for them
please benchmark on P4 & athlon
(ill remove the benchmarking code and the always slower variants as soon as p4/athlon benchmarks have been posted or commited)

Originally committed as revision 6573 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-10-07 11:15:10 +00:00
parent 21423ad9b7
commit ec8f483ab5
1 changed files with 63 additions and 1 deletions
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64
libavcodec/cabac.h
View File

@ -295,15 +295,77 @@ static inline void renorm_cabac_decoder(CABACContext *c){
}
static inline void renorm_cabac_decoder_once(CABACContext *c){
#ifdef ARCH_X86
int temp;
#if 0
//P3:683
asm(
"lea -0x20000(%0), %2 \n\t"
"shr $31, %2 \n\t" //FIXME 31->63 for x86-64
"shl %%cl, %0 \n\t"
"shl %%cl, %1 \n\t"
: "+r"(c->range), "+r"(c->low), "+c"(temp)
);
#elif 0
//P3:680
asm(
"cmp $0x20000, %0 \n\t"
"setb %%cl \n\t" //FIXME 31->63 for x86-64
"shl %%cl, %0 \n\t"
"shl %%cl, %1 \n\t"
: "+r"(c->range), "+r"(c->low), "+c"(temp)
);
#elif 1
int temp2;
//P3:665
asm(
"lea -0x20000(%0), %%eax \n\t"
"cdq \n\t"
"mov %0, %%eax \n\t"
"and %%edx, %0 \n\t"
"and %1, %%edx \n\t"
"add %%eax, %0 \n\t"
"add %%edx, %1 \n\t"
: "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
);
#elif 0
int temp2;
//P3:673
asm(
"cmp $0x20000, %0 \n\t"
"sbb %%edx, %%edx \n\t"
"mov %0, %%eax \n\t"
"and %%edx, %0 \n\t"
"and %1, %%edx \n\t"
"add %%eax, %0 \n\t"
"add %%edx, %1 \n\t"
: "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
);
#else
int temp2;
//P3:677
asm(
"cmp $0x20000, %0 \n\t"
"lea (%0, %0), %%eax \n\t"
"lea (%1, %1), %%edx \n\t"
"cmovb %%eax, %0 \n\t"
"cmovb %%edx, %1 \n\t"
: "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
);
#endif
#else
//P3:675
int shift= (uint32_t)(c->range - (0x200 << CABAC_BITS))>>31;
c->range<<= shift;
c->low <<= shift;
#endif
if(!(c->low & CABAC_MASK))
refill(c);
}
static int get_cabac(CABACContext *c, uint8_t * const state){
//FIXME gcc generates duplicate load/stores for c->low and c->range
START_TIMER
int s = *state;
int RangeLPS= c->lps_range[s][c->range>>(CABAC_BITS+7)]<<(CABAC_BITS+1);
int bit, lps_mask attribute_unused;
@ -342,7 +404,7 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
if(!(c->low & CABAC_MASK))
refill2(c);
#endif
STOP_TIMER("get_cabac")
return bit;
}