SDL_mixer_m68k.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2004 Sam Lantinga
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This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
slouken@libsdl.org
*/
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#include "SDL_config.h"
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/*
m68k assembly mix routines
Patrice Mandin
*/
#if defined(__M68000__) && defined(__GNUC__)
void SDL_MixAudio_m68k_U8(char* dst, char* src, long len, long volume, char* mix8)
{
__asm__ __volatile__ (
"tstl %2\n"
" beqs stoploop_u8\n"
"mixloop_u8:\n"
/* Mix a sample */
" moveq #0,%%d0\n"
" moveq #0,%%d1\n"
" moveb %1@+,%%d0\n" /* d0 = *src++ */
" sub #128,%%d0\n" /* d0 -= 128 */
" muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
" moveb %0@,%%d1\n" /* d1 = *dst */
" asr #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
" add #128,%%d0\n" /* d0 += 128 */
" add %%d1,%%d0\n"
" moveb %4@(%%d0:w),%0@+\n"
/* Loop till done */
" subql #1,%2\n"
" bhis mixloop_u8\n"
"stoploop_u8:\n"
: /* no return value */
: /* input */
"a"(dst), "a"(src), "d"(len), "d"(volume), "a"(mix8)
: /* clobbered registers */
"d0", "d1", "cc", "memory"
);
}
void SDL_MixAudio_m68k_S8(char* dst, char* src, long len, long volume)
{
__asm__ __volatile__ (
"tstl %2\n"
" beqs stoploop_s8\n"
" moveq #-128,%%d2\n"
" moveq #127,%%d3\n"
"mixloop_s8:\n"
/* Mix a sample */
" moveq #0,%%d0\n"
" moveq #0,%%d1\n"
" moveb %1@+,%%d0\n" /* d0 = *src++ */
" muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
" moveb %0@,%%d1\n" /* d1 = *dst */
" asr #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
" add %%d1,%%d0\n"
" cmp %%d2,%%d0\n"
" bges lower_limit_s8\n"
" move %%d2,%%d0\n"
"lower_limit_s8:\n"
" cmp %%d3,%%d0\n"
" bles upper_limit_s8\n"
" move %%d3,%%d0\n"
"upper_limit_s8:\n"
" moveb %%d0,%0@+\n"
/* Loop till done */
" subql #1,%2\n"
" bhis mixloop_s8\n"
"stoploop_s8:\n"
: /* no return value */
: /* input */
"a"(dst), "a"(src), "d"(len), "d"(volume)
: /* clobbered registers */
"d0", "d1", "d2", "d3", "cc", "memory"
);
}
void SDL_MixAudio_m68k_S16MSB(short* dst, short* src, long len, long volume)
{
__asm__ __volatile__ (
"tstl %2\n"
" beqs stoploop_s16msb\n"
" movel #-32768,%%d2\n"
" movel #32767,%%d3\n"
" lsrl #1,%2\n"
"mixloop_s16msb:\n"
/* Mix a sample */
" move %1@+,%%d0\n" /* d0 = *src++ */
" muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
" move %0@,%%d1\n" /* d1 = *dst */
" extl %%d1\n" /* extend d1 to 32 bits */
" asrl #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
" addl %%d1,%%d0\n"
" cmpl %%d2,%%d0\n"
" bges lower_limit_s16msb\n"
" move %%d2,%%d0\n"
"lower_limit_s16msb:\n"
" cmpl %%d3,%%d0\n"
" bles upper_limit_s16msb\n"
" move %%d3,%%d0\n"
"upper_limit_s16msb:\n"
" move %%d0,%0@+\n"
/* Loop till done */
" subql #1,%2\n"
" bhis mixloop_s16msb\n"
"stoploop_s16msb:\n"
: /* no return value */
: /* input */
"a"(dst), "a"(src), "d"(len), "d"(volume)
: /* clobbered registers */
"d0", "d1", "d2", "d3", "cc", "memory"
);
}
void SDL_MixAudio_m68k_S16LSB(short* dst, short* src, long len, long volume)
{
__asm__ __volatile__ (
"tstl %2\n"
" beqs stoploop_s16lsb\n"
" movel #-32768,%%d2\n"
" movel #32767,%%d3\n"
" lsrl #1,%2\n"
"mixloop_s16lsb:\n"
/* Mix a sample */
" move %1@+,%%d0\n" /* d0 = *src++ */
" rorw #8,%%d0\n"
" muls %3,%%d0\n" /* d0 *= volume (0<=volume<=128) */
" move %0@,%%d1\n" /* d1 = *dst */
" rorw #8,%%d1\n"
" extl %%d1\n" /* extend d1 to 32 bits */
" asrl #7,%%d0\n" /* d0 /= 128 (SDL_MIX_MAXVOLUME) */
" addl %%d1,%%d0\n"
" cmpl %%d2,%%d0\n"
" bges lower_limit_s16lsb\n"
" move %%d2,%%d0\n"
"lower_limit_s16lsb:\n"
" cmpl %%d3,%%d0\n"
" bles upper_limit_s16lsb\n"
" move %%d3,%%d0\n"
"upper_limit_s16lsb:\n"
" rorw #8,%%d0\n"
" move %%d0,%0@+\n"
/* Loop till done */
" subql #1,%2\n"
" bhis mixloop_s16lsb\n"
"stoploop_s16lsb:\n"
: /* no return value */
: /* input */
"a"(dst), "a"(src), "d"(len), "d"(volume)
: /* clobbered registers */
"d0", "d1", "d2", "d3", "cc", "memory"
);
}
#endif