/*
    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"

#if ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
// 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
////////////////////////////////////////////////

void
SDL_MixAudio_MMX_S16_VC(char *dst, char *src, unsigned int nSize, int volume)
{
    __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
////////////////////////////////////////////////

void
SDL_MixAudio_MMX_S8_VC(char *dst, char *src, unsigned int nSize, int volume)
{
    _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}
}

#endif                          /* SDL_ASSEMBLY_ROUTINES */
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