Skip to content
Permalink
Browse files

Added MMX audio mixing code for gcc (thanks Stephane!)

  • Loading branch information
slouken committed Nov 9, 2002
1 parent 2b60363 commit 4cbe470278ddcfb4f0d0267e7a1295d7b72d661a
Showing with 238 additions and 1 deletion.
  1. +1 −0 docs.html
  2. +3 −1 src/audio/Makefile.am
  3. +36 −0 src/audio/SDL_mixer.c
  4. +185 −0 src/audio/SDL_mixer_MMX.c
  5. +13 −0 src/audio/SDL_mixer_MMX.h
@@ -20,6 +20,7 @@ <H2>
Major changes since SDL 1.0.0:
</H2>
<UL>
<LI> 1.2.6: Added MMX audio mixing code for gcc (thanks Stephane!)
<LI> 1.2.6: Fixed potential dropped events under DirectInput
<LI> 1.2.6: Added Visual C++ 7 (.NET) projects (thanks James!)
<LI> 1.2.5: Added an environment variable SDL_HAS3BUTTONMOUSE for Quartz
@@ -22,7 +22,9 @@ COMMON_SRCS = \
SDL_mixer.c \
SDL_sysaudio.h \
SDL_wave.c \
SDL_wave.h
SDL_wave.h \
SDL_mixer_MMX.c \
SDL_mixer_MMX.h

libaudio_la_SOURCES = $(COMMON_SRCS)
libaudio_la_LIBADD = $(DRIVERS)
@@ -35,7 +35,24 @@ static char rcsid =
#include "SDL_mutex.h"
#include "SDL_timer.h"
#include "SDL_sysaudio.h"
#include "SDL_mixer_MMX.h"

/* Function to check the CPU flags */
#define MMX_CPU 0x800000
#ifdef USE_ASMBLIT
#define CPU_Flags() Hermes_X86_CPU()
#else
#define CPU_Flags() 0L
#endif

#ifdef USE_ASMBLIT
#define X86_ASSEMBLER
#define HermesConverterInterface void
#define HermesClearInterface void
#define STACKCALL

#include "HeadX86.h"
#endif

/* This table is used to add two sound values together and pin
* the value to avoid overflow. (used with permission from ARDI)
@@ -130,6 +147,15 @@ void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
break;

case AUDIO_S8: {

#if defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT)
if (CPU_Flags() & MMX_CPU)
{
SDL_MixAudio_MMX_S8((char*)dst,(char*)src,(unsigned int)len,(int)volume);
}
else
#endif
{
Sint8 *dst8, *src8;
Sint8 src_sample;
int dst_sample;
@@ -153,10 +179,19 @@ void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
++dst8;
++src8;
}
}
}
break;

case AUDIO_S16LSB: {
#if defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT)
if (CPU_Flags() & MMX_CPU)
{
SDL_MixAudio_MMX_S16((char*)dst,(char*)src,(unsigned int)len,(int)volume);
}
else
#endif
{
Sint16 src1, src2;
int dst_sample;
const int max_audioval = ((1<<(16-1))-1);
@@ -180,6 +215,7 @@ void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
dst[1] = dst_sample&0xFF;
dst += 2;
}
}
}
break;

@@ -0,0 +1,185 @@
// 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 %0,%%edi\n" // edi = dst
" movl %1,%%esi\n" // esi = src
" movl %3,%%eax\n" // eax = volume

" movl %2,%%ebx\n" // ebx = size

" shrl $4,%%ebx\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 (%%esi),%%mm1\n" // mm1 = a|b|c|d

" movq %%mm1,%%mm2\n" // mm2 = a|b|c|d

" movq 8(%%esi),%%mm4\n" // mm4 = e|f|g|h

// pré charger le buffer dst dans mm7
" movq (%%edi),%%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(%%edi),%%mm5\n" // mm5 = dst[1]

// diviser par 128
" psrad $7,%%mm1\n" // mm1 = a*v/128|b*v/128 , 128 = SDL_MIX_MAXVOLUME
" addl $16,%%esi\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,(%%edi)\n"

" paddsw %%mm5,%%mm6\n" // mm6 = adjust_volume(src)+dst

" movq %%mm6,8(%%edi)\n"

" addl $16,%%edi\n"

" dec %%ebx\n"

" jnz .mixloopS16\n"

" emms\n"

".endS16:\n"
:
: "m" (dst), "m"(src),"m"(size),
"m"(volume)
: "eax","ebx", "esi", "edi","memory"
);
}



////////////////////////////////////////////////
// Mixing for 8 bit signed buffers
////////////////////////////////////////////////

void SDL_MixAudio_MMX_S8(char* dst,char* src,unsigned int size,int volume)
{
__asm__ __volatile__ (

" movl %0,%%edi\n" // edi = dst
" movl %1,%%esi\n" // esi = src
" movl %3,%%eax\n" // eax = volume

" movd %%ebx,%%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,%%ebx\n" // ebx = size
" shr $3,%%ebx\n" // process 8 bytes per iteration = 8 samples

" cmp $0,%%ebx\n"
" je .endS8\n"

".align 16\n"
" .mixloopS8:\n"

" pxor %%mm2,%%mm2\n" // mm2 = 0
" movq (%%esi),%%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 (%%edi),%%mm2\n" // mm2 = destination

" pmullw %%mm0,%%mm1\n" // mm1 = v*a|v*b|v*c|v*d
" addl $8,%%esi\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,(%%edi)\n" // store back to ram
" addl $8,%%edi\n"

" dec %%ebx\n"

" jnz .mixloopS8\n"

".endS8:\n"
" emms\n"
:
: "m" (dst), "m"(src),"m"(size),
"m"(volume)
: "eax","ebx", "esi", "edi","memory"
);
}
#endif

@@ -0,0 +1,13 @@
// headers for MMX assembler version of SDL_MixAudio
// 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


#if defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT)
void SDL_MixAudio_MMX_S16(char* ,char* ,unsigned int ,int );
void SDL_MixAudio_MMX_S8(char* ,char* ,unsigned int ,int );
#endif

0 comments on commit 4cbe470

Please sign in to comment.