87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
/*
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* mix.cpp
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*
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* Copyright (C) 2007 Matt Ownby
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*
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* This file is part of DAPHNE, a laserdisc arcade game emulator
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*
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* DAPHNE is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* DAPHNE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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// mix.cpp
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#include "sound.h"
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#include "../io/mpo_mem.h"
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#include "mix.h"
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#ifdef DEBUG
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#include <assert.h>
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#endif
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// if we aren't using the MMX version
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#ifndef USE_MMX
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struct mix_s *g_pMixBufs = NULL;
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Uint8 *g_pSampleDst = 0;
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unsigned int g_uBytesToMix = 0;
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#endif
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// A C version of mix_mmx
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// mix_mmx is 2.5 times as fast on Pentium 4
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// NOTE : we always want this defined, even when using MMX, for the purpose of testing (see releasetest)
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void mix_c()
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{
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unsigned int uSamplesToMix = g_uBytesToMix >> 1;
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Uint8 *stream = g_pSampleDst;
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unsigned int sample = 0, val_to_store = 0;
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for (sample = 0; sample < uSamplesToMix; sample += 2)
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{
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int mixed_sample_1 = 0, mixed_sample_2 = 0; // left/right channels
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struct mix_s *cur = g_pMixBufs;
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// mix all sound chips
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while (cur)
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{
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mixed_sample_1 += LOAD_LIL_SINT16(((short *) cur->pMixBuf) + sample);
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mixed_sample_2 += LOAD_LIL_SINT16(((short *) cur->pMixBuf) + sample + 1);
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cur = cur->pNext;
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}
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DO_CLIP(mixed_sample_1);
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DO_CLIP(mixed_sample_2);
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// note: sample2 needs to be on top because this is little endian, hence LSB
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val_to_store =
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(((unsigned short) mixed_sample_2) << 16) | ((unsigned short) mixed_sample_1);
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STORE_LIL_UINT32(stream, val_to_store);
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stream += 4;
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}
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}
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#ifdef USE_MMX
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#ifdef DEBUG
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// debug version of mix MMX that does safety checking before the call. This obviously won't be used
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// during release builds.
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void debug_mix_mmx()
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{
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assert(((g_uBytesToMix % 8) == 0) && (g_uBytesToMix >= 8)); // mix MMX does 8 bytes at a time
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mix_mmx();
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}
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#endif // DEBUG
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#endif // NATIVE_CPU_X86
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