Mercurial > sdl-ios-xcode
view src/audio/SDL_mixer_m68k.c @ 2866:e532417a6977
Fixed SDL 1.2 compatibility problem.
The API specifies that SDL_OpenAudio() will fill out the 'desired' audio spec
with the correct samples and size set by the driver. This value is important
since it may be used by applications that size audio buffers, etc.
However, we want to allow advanced applications to call SDL_OpenAudioDevice()
which gets passed a const 'desired' parameter, and have the correct data filled
into the 'obtained' parameter, possibly allowing or not allowing format changes.
So... 'obtained' becomes the audio format the user callback is expected to use,
and we add flags to allow the application to specify which format changes are
allowed.
Note: We really need to add a way to query the 'obtained' audio spec.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 13 Dec 2008 06:36:47 +0000 |
| parents | 99210400e8b9 |
| children | efb79807afe1 |
line wrap: on
line source
/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 Sam Lantinga 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 */ #include "SDL_config.h" /* 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 /* vi: set ts=4 sw=4 expandtab: */