/*

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"

#include "SDL_mixer_MMX_VC.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)

// Converted to Intel ASM notation by Cth

// 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

////////////////////////////////////////////////

/* *INDENT-OFF* */

__asm

{

push edi

push esi

push ebx

mov edi, dst // edi = dst

mov esi, src // esi = src

mov eax, volume // eax = volume

mov ebx, nSize // ebx = size

shr ebx, 4 // process 16 bytes per iteration = 8 samples

jz endS16

pxor mm0, mm0

movd mm0, eax //%%eax,%%mm0

movq mm1, mm0 //%%mm0,%%mm1

psllq mm0, 16 //$16,%%mm0

por mm0, mm1 //%%mm1,%%mm0

psllq mm0, 16 //$16,%%mm0

por mm0, mm1 //%%mm1,%%mm0

psllq mm0, 16 //$16,%%mm0

por mm0, mm1 //%%mm1,%%mm0 // mm0 = vol|vol|vol|vol

#ifndef __WATCOMC__

align 16

#endif

mixloopS16:

movq mm1, [esi] //(%%esi),%%mm1\n" // mm1 = a|b|c|d

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

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

// pre charger le buffer dst dans mm7

movq mm7, [edi] //(%%edi),%%mm7\n" // mm7 = dst[0]"

// multiplier par le volume

pmullw mm1, mm0 //%%mm0,%%mm1\n" // mm1 = l(a*v)|l(b*v)|l(c*v)|l(d*v)

pmulhw mm2, mm0 //%%mm0,%%mm2\n" // mm2 = h(a*v)|h(b*v)|h(c*v)|h(d*v)

movq mm5, mm4 //%%mm4,%%mm5\n" // mm5 = e|f|g|h

pmullw mm4, mm0 //%%mm0,%%mm4\n" // mm4 = l(e*v)|l(f*v)|l(g*v)|l(h*v)

pmulhw mm5, mm0 //%%mm0,%%mm5\n" // mm5 = h(e*v)|h(f*v)|h(g*v)|h(h*v)

movq mm3, mm1 //%%mm1,%%mm3\n" // mm3 = l(a*v)|l(b*v)|l(c*v)|l(d*v)

punpckhwd mm1, mm2 //%%mm2,%%mm1\n" // mm1 = a*v|b*v

movq mm6, mm4 //%%mm4,%%mm6\n" // mm6 = l(e*v)|l(f*v)|l(g*v)|l(h*v)

punpcklwd mm3, mm2 //%%mm2,%%mm3\n" // mm3 = c*v|d*v

punpckhwd mm4, mm5 //%%mm5,%%mm4\n" // mm4 = e*f|f*v

punpcklwd mm6, mm5 //%%mm5,%%mm6\n" // mm6 = g*v|h*v

// pre charger le buffer dst dans mm5

movq mm5, [edi + 8] //8(%%edi),%%mm5\n" // mm5 = dst[1]

// diviser par 128

psrad mm1, 7 //$7,%%mm1\n" // mm1 = a*v/128|b*v/128 , 128 = SDL_MIX_MAXVOLUME

add esi, 16 //$16,%%esi\n"

psrad mm3, 7 //$7,%%mm3\n" // mm3 = c*v/128|d*v/128

psrad mm4, 7 //$7,%%mm4\n" // mm4 = e*v/128|f*v/128

// mm1 = le sample avec le volume modifie

packssdw mm3, mm1 //%%mm1,%%mm3\n" // mm3 = s(a*v|b*v|c*v|d*v)

psrad mm6, 7 //$7,%%mm6\n" // mm6= g*v/128|h*v/128

paddsw mm3, mm7 //%%mm7,%%mm3\n" // mm3 = adjust_volume(src)+dst

// mm4 = le sample avec le volume modifie

packssdw mm6, mm4 //%%mm4,%%mm6\n" // mm6 = s(e*v|f*v|g*v|h*v)

movq [edi], mm3 //%%mm3,(%%edi)\n"

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

movq [edi + 8], mm6 //%%mm6,8(%%edi)\n"

add edi, 16 //$16,%%edi\n"

dec ebx //%%ebx\n"

jnz mixloopS16

ends16:

emms

pop ebx

pop esi

pop edi

}

////////////////////////////////////////////////

// Mixing for 8 bit signed buffers

////////////////////////////////////////////////

/* *INDENT-OFF* */

_asm

{

push edi

push esi

push ebx

mov edi, dst //movl %0,%%edi // edi = dst

mov esi, src //%1,%%esi // esi = src

mov eax, volume //%3,%%eax // eax = volume

movd mm0, eax //%%eax,%%mm0

movq mm1, mm0 //%%mm0,%%mm1

psllq mm0, 16 //$16,%%mm0

por mm0, mm1 //%%mm1,%%mm0

psllq mm0, 16 //$16,%%mm0

por mm0, mm1 //%%mm1,%%mm0

psllq mm0, 16 //$16,%%mm0

por mm0, mm1 //%%mm1,%%mm0

mov ebx, nSize //%2,%%ebx // ebx = size

shr ebx, 3 //$3,%%ebx // process 8 bytes per iteration = 8 samples

cmp ebx, 0 //$0,%%ebx

je endS8

#ifndef __WATCOMC__

align 16

#endif

mixloopS8:

pxor mm2, mm2 //%%mm2,%%mm2 // mm2 = 0

movq mm1, [esi] //(%%esi),%%mm1 // mm1 = a|b|c|d|e|f|g|h

movq mm3, mm1 //%%mm1,%%mm3 // 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 mm2, mm1 //%%mm1,%%mm2 // mm2 = 11111111|00000000|00000000....

punpckhbw mm1, mm2 //%%mm2,%%mm1 // mm1 = 0|a|0|b|0|c|0|d

punpcklbw mm3, mm2 //%%mm2,%%mm3 // mm3 = 0|e|0|f|0|g|0|h

movq mm2, [edi] //(%%edi),%%mm2 // mm2 = destination

pmullw mm1, mm0 //%%mm0,%%mm1 // mm1 = v*a|v*b|v*c|v*d

add esi, 8 //$8,%%esi

pmullw mm3, mm0 //%%mm0,%%mm3 // mm3 = v*e|v*f|v*g|v*h

psraw mm1, 7 //$7,%%mm1 // mm1 = v*a/128|v*b/128|v*c/128|v*d/128

psraw mm3, 7 //$7,%%mm3 // mm3 = v*e/128|v*f/128|v*g/128|v*h/128

packsswb mm3, mm1 //%%mm1,%%mm3 // 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 mm3, mm2 //%%mm2,%%mm3 // add to destination buffer

movq [edi], mm3 //%%mm3,(%%edi) // store back to ram

add edi, 8 //$8,%%edi

dec ebx //%%ebx

jnz mixloopS8

endS8:

emms

pop ebx

pop esi

pop edi

}