src/audio/SDL_mixer_MMX.c
author Sam Lantinga <slouken@libsdl.org>
Tue, 09 May 2006 08:52:54 +0000
changeset 1794 5605a9820134
parent 1612 97d0966f4bf7
child 1662 782fd950bd46
child 1895 c121d94672cb
child 4159 a1b03ba2fcd0
permissions -rw-r--r--
Fixed bug #137 If SDL_OpenAudio() is passed zero for the desired format fields, the following environment variables will be used to fill them in: SDL_AUDIO_FREQUENCY SDL_AUDIO_FORMAT SDL_AUDIO_CHANNELS SDL_AUDIO_SAMPLES If an environment variable is not specified, it will be set to a reasonable default value.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    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"

/*
    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(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
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 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"
	 );
}



/*////////////////////////////////////////////// */
/* 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 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"
	 );
}
#endif