src/audio/SDL_mixer.c - third_party/sdl - Git at Google

 /*
     SDL - Simple DirectMedia Layer
     Copyright (C) 1997-2009 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"

 /* This provides the default mixing callback for the SDL audio routines */

 #include "SDL_cpuinfo.h"
 #include "SDL_timer.h"
 #include "SDL_audio.h"
 #include "SDL_sysaudio.h"
 #include "SDL_mixer_MMX.h"
 #include "SDL_mixer_MMX_VC.h"
 #include "SDL_mixer_m68k.h"

 /* This table is used to add two sound values together and pin
  * the value to avoid overflow.  (used with permission from ARDI)
  * Changed to use 0xFE instead of 0xFF for better sound quality.
  */
 static const Uint8 mix8[] =
 {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03,
   0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
   0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
   0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
   0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
   0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
   0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
   0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
   0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
   0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
   0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
   0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
   0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
   0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
   0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
   0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
   0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
   0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
   0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
   0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
   0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
   0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
   0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
   0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE
 };

 /* The volume ranges from 0 - 128 */
 #define ADJUST_VOLUME(s, v)	(s = (s*v)/SDL_MIX_MAXVOLUME)
 #define ADJUST_VOLUME_U8(s, v)	(s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)

 void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
 {
 	Uint16 format;

 	if ( volume == 0 ) {
 		return;
 	}
 	/* Mix the user-level audio format */
 	if ( current_audio ) {
 		if ( current_audio->convert.needed ) {
 			format = current_audio->convert.src_format;
 		} else {
 			format = current_audio->spec.format;
 		}
 	} else {
   		/* HACK HACK HACK */
 		format = AUDIO_S16;
 	}
 	switch (format) {

 		case AUDIO_U8: {
 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 			SDL_MixAudio_m68k_U8((char*)dst,(char*)src,(unsigned long)len,(long)volume,(char *)mix8);
 #else
 			Uint8 src_sample;

 			while ( len-- ) {
 				src_sample = *src;
 				ADJUST_VOLUME_U8(src_sample, volume);
 				*dst = mix8[*dst+src_sample];
 				++dst;
 				++src;
 			}
 #endif
 		}
 		break;

 		case AUDIO_S8: {
 #if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
 			if (SDL_HasMMX())
 			{
 				SDL_MixAudio_MMX_S8((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 			}
 			else
 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
 			if (SDL_HasMMX())
 			{
 				SDL_MixAudio_MMX_S8_VC((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 			}
 			else
 #endif
 #endif

 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 			SDL_MixAudio_m68k_S8((char*)dst,(char*)src,(unsigned long)len,(long)volume);
 #else
 			{
 			Sint8 *dst8, *src8;
 			Sint8 src_sample;
 			int dst_sample;
 			const int max_audioval = ((1<<(8-1))-1);
 			const int min_audioval = -(1<<(8-1));

 			src8 = (Sint8 *)src;
 			dst8 = (Sint8 *)dst;
 			while ( len-- ) {
 				src_sample = *src8;
 				ADJUST_VOLUME(src_sample, volume);
 				dst_sample = *dst8 + src_sample;
 				if ( dst_sample > max_audioval ) {
 					*dst8 = max_audioval;
 				} else
 				if ( dst_sample < min_audioval ) {
 					*dst8 = min_audioval;
 				} else {
 					*dst8 = dst_sample;
 				}
 				++dst8;
 				++src8;
 			}
 			}
 #endif
 		}
 		break;

 		case AUDIO_S16LSB: {
 #if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
 			if (SDL_HasMMX())
 			{
 				SDL_MixAudio_MMX_S16((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 			}
                         else
 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
 			if (SDL_HasMMX())
 			{
 				SDL_MixAudio_MMX_S16_VC((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 			}
 			else
 #endif
 #endif

 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 			SDL_MixAudio_m68k_S16LSB((short*)dst,(short*)src,(unsigned long)len,(long)volume);
 #else
 			{
 			Sint16 src1, src2;
 			int dst_sample;
 			const int max_audioval = ((1<<(16-1))-1);
 			const int min_audioval = -(1<<(16-1));

 			len /= 2;
 			while ( len-- ) {
 				src1 = ((src[1])<<8|src[0]);
 				ADJUST_VOLUME(src1, volume);
 				src2 = ((dst[1])<<8|dst[0]);
 				src += 2;
 				dst_sample = src1+src2;
 				if ( dst_sample > max_audioval ) {
 					dst_sample = max_audioval;
 				} else
 				if ( dst_sample < min_audioval ) {
 					dst_sample = min_audioval;
 				}
 				dst[0] = dst_sample&0xFF;
 				dst_sample >>= 8;
 				dst[1] = dst_sample&0xFF;
 				dst += 2;
 			}
 			}
 #endif
 		}
 		break;

 		case AUDIO_S16MSB: {
 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 			SDL_MixAudio_m68k_S16MSB((short*)dst,(short*)src,(unsigned long)len,(long)volume);
 #else
 			Sint16 src1, src2;
 			int dst_sample;
 			const int max_audioval = ((1<<(16-1))-1);
 			const int min_audioval = -(1<<(16-1));

 			len /= 2;
 			while ( len-- ) {
 				src1 = ((src[0])<<8|src[1]);
 				ADJUST_VOLUME(src1, volume);
 				src2 = ((dst[0])<<8|dst[1]);
 				src += 2;
 				dst_sample = src1+src2;
 				if ( dst_sample > max_audioval ) {
 					dst_sample = max_audioval;
 				} else
 				if ( dst_sample < min_audioval ) {
 					dst_sample = min_audioval;
 				}
 				dst[1] = dst_sample&0xFF;
 				dst_sample >>= 8;
 				dst[0] = dst_sample&0xFF;
 				dst += 2;
 			}
 #endif
 		}
 		break;

 		default: /* If this happens... FIXME! */
 			SDL_SetError("SDL_MixAudio(): unknown audio format");
 			return;
 	}
 }
	/*
	SDL - Simple DirectMedia Layer
	Copyright (C) 1997-2009 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"

	/* This provides the default mixing callback for the SDL audio routines */

	#include "SDL_cpuinfo.h"
	#include "SDL_timer.h"
	#include "SDL_audio.h"
	#include "SDL_sysaudio.h"
	#include "SDL_mixer_MMX.h"
	#include "SDL_mixer_MMX_VC.h"
	#include "SDL_mixer_m68k.h"

	/* This table is used to add two sound values together and pin
	* the value to avoid overflow. (used with permission from ARDI)
	* Changed to use 0xFE instead of 0xFF for better sound quality.
	*/
	static const Uint8 mix8[] =
	{
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03,
	0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
	0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
	0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
	0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
	0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
	0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
	0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
	0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
	0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
	0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
	0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
	0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
	0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
	0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
	0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
	0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
	0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
	0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
	0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
	0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
	0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
	0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
	0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE
	};

	/* The volume ranges from 0 - 128 */
	#define ADJUST_VOLUME(s, v) (s = (s*v)/SDL_MIX_MAXVOLUME)
	#define ADJUST_VOLUME_U8(s, v) (s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)

	void SDL_MixAudio (Uint8 dst, const Uint8 src, Uint32 len, int volume)
	{
	Uint16 format;

	if ( volume == 0 ) {
	return;
	}
	/* Mix the user-level audio format */
	if ( current_audio ) {
	if ( current_audio->convert.needed ) {
	format = current_audio->convert.src_format;
	} else {
	format = current_audio->spec.format;
	}
	} else {
	/* HACK HACK HACK */
	format = AUDIO_S16;
	}
	switch (format) {

	case AUDIO_U8: {
	#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
	SDL_MixAudio_m68k_U8((char)dst,(char)src,(unsigned long)len,(long)volume,(char *)mix8);
	#else
	Uint8 src_sample;

	while ( len-- ) {
	src_sample = *src;
	ADJUST_VOLUME_U8(src_sample, volume);
	dst = mix8[dst+src_sample];
	++dst;
	++src;
	}
	#endif
	}
	break;

	case AUDIO_S8: {
	#if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
	#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
	if (SDL_HasMMX())
	{
	SDL_MixAudio_MMX_S8((char)dst,(char)src,(unsigned int)len,(int)volume);
	}
	else
	#elif ((defined(_MSC_VER) && defined(_M_IX86)) \|\| defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
	if (SDL_HasMMX())
	{
	SDL_MixAudio_MMX_S8_VC((char)dst,(char)src,(unsigned int)len,(int)volume);
	}
	else
	#endif
	#endif

	#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
	SDL_MixAudio_m68k_S8((char)dst,(char)src,(unsigned long)len,(long)volume);
	#else
	{
	Sint8 dst8, src8;
	Sint8 src_sample;
	int dst_sample;
	const int max_audioval = ((1<<(8-1))-1);
	const int min_audioval = -(1<<(8-1));

	src8 = (Sint8 *)src;
	dst8 = (Sint8 *)dst;
	while ( len-- ) {
	src_sample = *src8;
	ADJUST_VOLUME(src_sample, volume);
	dst_sample = *dst8 + src_sample;
	if ( dst_sample > max_audioval ) {
	*dst8 = max_audioval;
	} else
	if ( dst_sample < min_audioval ) {
	*dst8 = min_audioval;
	} else {
	*dst8 = dst_sample;
	}
	++dst8;
	++src8;
	}
	}
	#endif
	}
	break;

	case AUDIO_S16LSB: {
	#if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
	#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
	if (SDL_HasMMX())
	{
	SDL_MixAudio_MMX_S16((char)dst,(char)src,(unsigned int)len,(int)volume);
	}
	else
	#elif ((defined(_MSC_VER) && defined(_M_IX86)) \|\| defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
	if (SDL_HasMMX())
	{
	SDL_MixAudio_MMX_S16_VC((char)dst,(char)src,(unsigned int)len,(int)volume);
	}
	else
	#endif
	#endif

	#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
	SDL_MixAudio_m68k_S16LSB((short)dst,(short)src,(unsigned long)len,(long)volume);
	#else
	{
	Sint16 src1, src2;
	int dst_sample;
	const int max_audioval = ((1<<(16-1))-1);
	const int min_audioval = -(1<<(16-1));

	len /= 2;
	while ( len-- ) {
	src1 = ((src[1])<<8\|src[0]);
	ADJUST_VOLUME(src1, volume);
	src2 = ((dst[1])<<8\|dst[0]);
	src += 2;
	dst_sample = src1+src2;
	if ( dst_sample > max_audioval ) {
	dst_sample = max_audioval;
	} else
	if ( dst_sample < min_audioval ) {
	dst_sample = min_audioval;
	}
	dst[0] = dst_sample&0xFF;
	dst_sample >>= 8;
	dst[1] = dst_sample&0xFF;
	dst += 2;
	}
	}
	#endif
	}
	break;

	case AUDIO_S16MSB: {
	#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
	SDL_MixAudio_m68k_S16MSB((short)dst,(short)src,(unsigned long)len,(long)volume);
	#else
	Sint16 src1, src2;
	int dst_sample;
	const int max_audioval = ((1<<(16-1))-1);
	const int min_audioval = -(1<<(16-1));

	len /= 2;
	while ( len-- ) {
	src1 = ((src[0])<<8\|src[1]);
	ADJUST_VOLUME(src1, volume);
	src2 = ((dst[0])<<8\|dst[1]);
	src += 2;
	dst_sample = src1+src2;
	if ( dst_sample > max_audioval ) {
	dst_sample = max_audioval;
	} else
	if ( dst_sample < min_audioval ) {
	dst_sample = min_audioval;
	}
	dst[1] = dst_sample&0xFF;
	dst_sample >>= 8;
	dst[0] = dst_sample&0xFF;
	dst += 2;
	}
	#endif
	}
	break;

	default: /* If this happens... FIXME! */
	SDL_SetError("SDL_MixAudio(): unknown audio format");
	return;
	}
	}