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SDL_mixer_MMX.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2010 Sam Lantinga
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This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
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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
***********************************************/
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#if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
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#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
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void
SDL_MixAudio_MMX_S16(char *dst, char *src, unsigned int size, int volume)
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__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 8\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");
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/*////////////////////////////////////////////// */
/* Mixing for 8 bit signed buffers */
/*////////////////////////////////////////////// */
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void
SDL_MixAudio_MMX_S8(char *dst, char *src, unsigned int size, int volume)
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__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 8\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");
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#endif /* SDL_BUGGY_MMX_MIXERS */
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/* vi: set ts=4 sw=4 expandtab: */