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SDL_mixer_m68k.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2010 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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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
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Lesser General Public License for more details.
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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
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Sam Lantinga
slouken@libsdl.org
*/
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#include "SDL_config.h"
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/*
m68k assembly mix routines
Patrice Mandin
*/
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#if defined(__M68000__) && !defined(__mcoldfire__) && defined(__GNUC__)
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void
SDL_MixAudio_m68k_U8(char *dst, char *src, long len, long volume, char *mix8)
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__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");
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void
SDL_MixAudio_m68k_S8(char *dst, char *src, long len, long volume)
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__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");
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void
SDL_MixAudio_m68k_S16MSB(short *dst, short *src, long len, long volume)
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__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");
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void
SDL_MixAudio_m68k_S16LSB(short *dst, short *src, long len, long volume)
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__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");
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}
#endif
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/* vi: set ts=4 sw=4 expandtab: */