src/audio/SDL_mixer_m68k.c

   1 /*
   2     SDL - Simple DirectMedia Layer
   3     Copyright (C) 1997-2004 Sam Lantinga
   4
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Library General Public
   7     License as published by the Free Software Foundation; either
   8     version 2 of the License, or (at your option) any later version.
   9
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Library General Public License for more details.
  14
  15     You should have received a copy of the GNU Library General Public
  16     License along with this library; if not, write to the Free
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18
  19     Sam Lantinga
  20     slouken@libsdl.org
  21 */
  22 #include "SDL_config.h"
  23
  24 /*
  25         m68k assembly mix routines
  26
  27         Patrice Mandin
  28 */
  29
  30 #if defined(__M68000__) && defined(__GNUC__)
  31 void SDL_MixAudio_m68k_U8(char* dst, char* src, long len, long volume, char* mix8)
  32 {
  33     __asm__ __volatile__ (
  34
  35         "tstl   %2\n"
  36 "       beqs    stoploop_u8\n"
  37 "mixloop_u8:\n"
  38
  39         /* Mix a sample */
  40
  41 "       moveq   #0,%%d0\n"
  42 "       moveq   #0,%%d1\n"
  43
  44 "       moveb   %1@+,%%d0\n"    /* d0 = *src++ */
  45 "       sub     #128,%%d0\n"    /* d0 -= 128 */
  46 "       muls    %3,%%d0\n"      /* d0 *= volume (0<=volume<=128) */
  47 "       moveb   %0@,%%d1\n"     /* d1 = *dst */
  48 "       asr     #7,%%d0\n"      /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
  49 "       add     #128,%%d0\n"    /* d0 += 128 */
  50
  51 "       add     %%d1,%%d0\n"
  52
  53 "       moveb   %4@(%%d0:w),%0@+\n"
  54
  55         /* Loop till done */
  56
  57 "       subql   #1,%2\n"
  58 "       bhis    mixloop_u8\n"
  59 "stoploop_u8:\n"
  60
  61          : /* no return value */
  62          : /* input */
  63                 "a"(dst), "a"(src), "d"(len), "d"(volume), "a"(mix8)
  64          : /* clobbered registers */
  65                 "d0", "d1", "cc", "memory"
  66          );
  67 }
  68
  69 void SDL_MixAudio_m68k_S8(char* dst, char* src, long len, long volume)
  70 {
  71     __asm__ __volatile__ (
  72
  73         "tstl   %2\n"
  74 "       beqs    stoploop_s8\n"
  75 "       moveq   #-128,%%d2\n"
  76 "       moveq   #127,%%d3\n"
  77 "mixloop_s8:\n"
  78
  79         /* Mix a sample */
  80
  81 "       moveq   #0,%%d0\n"
  82 "       moveq   #0,%%d1\n"
  83
  84 "       moveb   %1@+,%%d0\n"    /* d0 = *src++ */
  85 "       muls    %3,%%d0\n"      /* d0 *= volume (0<=volume<=128) */
  86 "       moveb   %0@,%%d1\n"     /* d1 = *dst */
  87 "       asr     #7,%%d0\n"      /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
  88
  89 "       add     %%d1,%%d0\n"
  90
  91 "       cmp     %%d2,%%d0\n"
  92 "       bges    lower_limit_s8\n"
  93 "       move    %%d2,%%d0\n"
  94 "lower_limit_s8:\n"
  95
  96 "       cmp     %%d3,%%d0\n"
  97 "       bles    upper_limit_s8\n"
  98 "       move    %%d3,%%d0\n"
  99 "upper_limit_s8:\n"
 100 "       moveb   %%d0,%0@+\n"
 101
 102         /* Loop till done */
 103
 104 "       subql   #1,%2\n"
 105 "       bhis    mixloop_s8\n"
 106 "stoploop_s8:\n"
 107
 108          : /* no return value */
 109          : /* input */
 110                 "a"(dst), "a"(src), "d"(len), "d"(volume)
 111          : /* clobbered registers */
 112                 "d0", "d1", "d2", "d3", "cc", "memory"
 113          );
 114 }
 115
 116 void SDL_MixAudio_m68k_S16MSB(short* dst, short* src, long len, long volume)
 117 {
 118     __asm__ __volatile__ (
 119
 120         "tstl   %2\n"
 121 "       beqs    stoploop_s16msb\n"
 122 "       movel   #-32768,%%d2\n"
 123 "       movel   #32767,%%d3\n"
 124 "       lsrl    #1,%2\n"
 125 "mixloop_s16msb:\n"
 126
 127         /* Mix a sample */
 128
 129 "       move    %1@+,%%d0\n"    /* d0 = *src++ */
 130 "       muls    %3,%%d0\n"      /* d0 *= volume (0<=volume<=128) */
 131 "       move    %0@,%%d1\n"     /* d1 = *dst */
 132 "       extl    %%d1\n"         /* extend d1 to 32 bits */
 133 "       asrl    #7,%%d0\n"      /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
 134
 135 "       addl    %%d1,%%d0\n"
 136
 137 "       cmpl    %%d2,%%d0\n"
 138 "       bges    lower_limit_s16msb\n"
 139 "       move    %%d2,%%d0\n"
 140 "lower_limit_s16msb:\n"
 141
 142 "       cmpl    %%d3,%%d0\n"
 143 "       bles    upper_limit_s16msb\n"
 144 "       move    %%d3,%%d0\n"
 145 "upper_limit_s16msb:\n"
 146 "       move    %%d0,%0@+\n"
 147
 148         /* Loop till done */
 149
 150 "       subql   #1,%2\n"
 151 "       bhis    mixloop_s16msb\n"
 152 "stoploop_s16msb:\n"
 153
 154          : /* no return value */
 155          : /* input */
 156                 "a"(dst), "a"(src), "d"(len), "d"(volume)
 157          : /* clobbered registers */
 158                 "d0", "d1", "d2", "d3", "cc", "memory"
 159          );
 160 }
 161
 162 void SDL_MixAudio_m68k_S16LSB(short* dst, short* src, long len, long volume)
 163 {
 164     __asm__ __volatile__ (
 165
 166         "tstl   %2\n"
 167 "       beqs    stoploop_s16lsb\n"
 168 "       movel   #-32768,%%d2\n"
 169 "       movel   #32767,%%d3\n"
 170 "       lsrl    #1,%2\n"
 171 "mixloop_s16lsb:\n"
 172
 173         /* Mix a sample */
 174
 175 "       move    %1@+,%%d0\n"    /* d0 = *src++ */
 176 "       rorw    #8,%%d0\n"
 177 "       muls    %3,%%d0\n"      /* d0 *= volume (0<=volume<=128) */
 178 "       move    %0@,%%d1\n"     /* d1 = *dst */
 179 "       rorw    #8,%%d1\n"
 180 "       extl    %%d1\n"         /* extend d1 to 32 bits */
 181 "       asrl    #7,%%d0\n"      /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
 182
 183 "       addl    %%d1,%%d0\n"
 184
 185 "       cmpl    %%d2,%%d0\n"
 186 "       bges    lower_limit_s16lsb\n"
 187 "       move    %%d2,%%d0\n"
 188 "lower_limit_s16lsb:\n"
 189
 190 "       cmpl    %%d3,%%d0\n"
 191 "       bles    upper_limit_s16lsb\n"
 192 "       move    %%d3,%%d0\n"
 193 "upper_limit_s16lsb:\n"
 194 "       rorw    #8,%%d0\n"
 195 "       move    %%d0,%0@+\n"
 196
 197         /* Loop till done */
 198
 199 "       subql   #1,%2\n"
 200 "       bhis    mixloop_s16lsb\n"
 201 "stoploop_s16lsb:\n"
 202
 203          : /* no return value */
 204          : /* input */
 205                 "a"(dst), "a"(src), "d"(len), "d"(volume)
 206          : /* clobbered registers */
 207                 "d0", "d1", "d2", "d3", "cc", "memory"
 208          );
 209 }
 210 #endif
 211