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dont use C-asm loops and unroll once float_to_int16_3dnow() 

30% faster

Originally committed as revision 14102 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2008-07-07 20:46:03 +00:00
parent 00496302d6
commit 63b737d4f9
1 changed files with 19 additions and 12 deletions
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31
libavcodec/i386/dsputil_mmx.c
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@ -2024,18 +2024,25 @@ static void vector_fmul_add_add_sse(float *dst, const float *src0, const float *
static void float_to_int16_3dnow(int16_t *dst, const float *src, int len){
// not bit-exact: pf2id uses different rounding than C and SSE
int i;
for(i=0; i<len; i+=4) {
asm volatile(
"pf2id %1, %%mm0 \n\t"
"pf2id %2, %%mm1 \n\t"
"packssdw %%mm1, %%mm0 \n\t"
"movq %%mm0, %0 \n\t"
:"=m"(dst[i])
:"m"(src[i]), "m"(src[i+2])
);
}
asm volatile("femms");
asm volatile(
"add %0 , %0 \n\t"
"lea (%2,%0,2) , %2 \n\t"
"add %0 , %1 \n\t"
"neg %0 \n\t"
"1: \n\t"
"pf2id (%2,%0,2) , %%mm0 \n\t"
"pf2id 8(%2,%0,2) , %%mm1 \n\t"
"pf2id 16(%2,%0,2) , %%mm2 \n\t"
"pf2id 24(%2,%0,2) , %%mm3 \n\t"
"packssdw %%mm1 , %%mm0 \n\t"
"packssdw %%mm3 , %%mm2 \n\t"
"movq %%mm0 , (%1,%0) \n\t"
"movq %%mm2 , 8(%1,%0) \n\t"
"add $16 , %0 \n\t"
" js 1b \n\t"
"femms \n\t"
:"+r"(len), "+r"(dst), "+r"(src)
);
}
static void float_to_int16_sse(int16_t *dst, const float *src, int len){
int i;