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SDL_mixer_MMX.c
183 lines (122 loc) · 4.25 KB
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SDL_mixer_MMX.c
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/*
MMX assembler version of SDL_MixAudio for signed little endian 16 bit samples and signed 8 bit samples
Copyright 2002 Stephane Marchesin (stephane.marchesin@wanadoo.fr)
This code is licensed under the LGPL (see COPYING for details)
Assumes buffer size in bytes is a multiple of 16
Assumes SDL_MIX_MAXVOLUME = 128
*/
/***********************************************
* Mixing for 16 bit signed buffers
***********************************************/
#if defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT)
void SDL_MixAudio_MMX_S16(char* dst,char* src,unsigned int size,int volume)
{
__asm__ __volatile__ (
" movl %3,%%eax\n" // eax = volume
" movl %2,%%edx\n" // edx = size
" shrl $4,%%edx\n" // process 16 bytes per iteration = 8 samples
" jz .endS16\n"
" pxor %%mm0,%%mm0\n"
" movd %%eax,%%mm0\n"
" movq %%mm0,%%mm1\n"
" psllq $16,%%mm0\n"
" por %%mm1,%%mm0\n"
" psllq $16,%%mm0\n"
" por %%mm1,%%mm0\n"
" psllq $16,%%mm0\n"
" por %%mm1,%%mm0\n" // mm0 = vol|vol|vol|vol
".align 16\n"
" .mixloopS16:\n"
" movq (%1),%%mm1\n" // mm1 = a|b|c|d
" movq %%mm1,%%mm2\n" // mm2 = a|b|c|d
" movq 8(%1),%%mm4\n" // mm4 = e|f|g|h
// pré charger le buffer dst dans mm7
" movq (%0),%%mm7\n" // mm7 = dst[0]"
// multiplier par le volume
" pmullw %%mm0,%%mm1\n" // mm1 = l(a*v)|l(b*v)|l(c*v)|l(d*v)
" pmulhw %%mm0,%%mm2\n" // mm2 = h(a*v)|h(b*v)|h(c*v)|h(d*v)
" movq %%mm4,%%mm5\n" // mm5 = e|f|g|h
" pmullw %%mm0,%%mm4\n" // mm4 = l(e*v)|l(f*v)|l(g*v)|l(h*v)
" pmulhw %%mm0,%%mm5\n" // mm5 = h(e*v)|h(f*v)|h(g*v)|h(h*v)
" movq %%mm1,%%mm3\n" // mm3 = l(a*v)|l(b*v)|l(c*v)|l(d*v)
" punpckhwd %%mm2,%%mm1\n" // mm1 = a*v|b*v
" movq %%mm4,%%mm6\n" // mm6 = l(e*v)|l(f*v)|l(g*v)|l(h*v)
" punpcklwd %%mm2,%%mm3\n" // mm3 = c*v|d*v
" punpckhwd %%mm5,%%mm4\n" // mm4 = e*f|f*v
" punpcklwd %%mm5,%%mm6\n" // mm6 = g*v|h*v
// pré charger le buffer dst dans mm5
" movq 8(%0),%%mm5\n" // mm5 = dst[1]
// diviser par 128
" psrad $7,%%mm1\n" // mm1 = a*v/128|b*v/128 , 128 = SDL_MIX_MAXVOLUME
" add $16,%1\n"
" psrad $7,%%mm3\n" // mm3 = c*v/128|d*v/128
" psrad $7,%%mm4\n" // mm4 = e*v/128|f*v/128
// mm1 = le sample avec le volume modifié
" packssdw %%mm1,%%mm3\n" // mm3 = s(a*v|b*v|c*v|d*v)
" psrad $7,%%mm6\n" // mm6= g*v/128|h*v/128
" paddsw %%mm7,%%mm3\n" // mm3 = adjust_volume(src)+dst
// mm4 = le sample avec le volume modifié
" packssdw %%mm4,%%mm6\n" // mm6 = s(e*v|f*v|g*v|h*v)
" movq %%mm3,(%0)\n"
" paddsw %%mm5,%%mm6\n" // mm6 = adjust_volume(src)+dst
" movq %%mm6,8(%0)\n"
" add $16,%0\n"
" dec %%edx\n"
" jnz .mixloopS16\n"
" emms\n"
".endS16:\n"
:
: "r" (dst), "r"(src),"m"(size),
"m"(volume)
: "eax","edx","memory"
);
}
////////////////////////////////////////////////
// Mixing for 8 bit signed buffers
////////////////////////////////////////////////
void SDL_MixAudio_MMX_S8(char* dst,char* src,unsigned int size,int volume)
{
__asm__ __volatile__ (
" movl %3,%%eax\n" // eax = volume
" movd %%eax,%%mm0\n"
" movq %%mm0,%%mm1\n"
" psllq $16,%%mm0\n"
" por %%mm1,%%mm0\n"
" psllq $16,%%mm0\n"
" por %%mm1,%%mm0\n"
" psllq $16,%%mm0\n"
" por %%mm1,%%mm0\n"
" movl %2,%%edx\n" // edx = size
" shr $3,%%edx\n" // process 8 bytes per iteration = 8 samples
" cmp $0,%%edx\n"
" je .endS8\n"
".align 16\n"
" .mixloopS8:\n"
" pxor %%mm2,%%mm2\n" // mm2 = 0
" movq (%1),%%mm1\n" // mm1 = a|b|c|d|e|f|g|h
" movq %%mm1,%%mm3\n" // mm3 = a|b|c|d|e|f|g|h
// on va faire le "sign extension" en faisant un cmp avec 0 qui retourne 1 si <0, 0 si >0
" pcmpgtb %%mm1,%%mm2\n" // mm2 = 11111111|00000000|00000000....
" punpckhbw %%mm2,%%mm1\n" // mm1 = 0|a|0|b|0|c|0|d
" punpcklbw %%mm2,%%mm3\n" // mm3 = 0|e|0|f|0|g|0|h
" movq (%0),%%mm2\n" // mm2 = destination
" pmullw %%mm0,%%mm1\n" // mm1 = v*a|v*b|v*c|v*d
" add $8,%1\n"
" pmullw %%mm0,%%mm3\n" // mm3 = v*e|v*f|v*g|v*h
" psraw $7,%%mm1\n" // mm1 = v*a/128|v*b/128|v*c/128|v*d/128
" psraw $7,%%mm3\n" // mm3 = v*e/128|v*f/128|v*g/128|v*h/128
" packsswb %%mm1,%%mm3\n" // mm1 = v*a/128|v*b/128|v*c/128|v*d/128|v*e/128|v*f/128|v*g/128|v*h/128
" paddsb %%mm2,%%mm3\n" // add to destination buffer
" movq %%mm3,(%0)\n" // store back to ram
" add $8,%0\n"
" dec %%edx\n"
" jnz .mixloopS8\n"
".endS8:\n"
" emms\n"
:
: "r" (dst), "r"(src),"m"(size),
"m"(volume)
: "eax","edx","memory"
);
}
#endif