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https://github.com/libretro/beetle-pce-fast-libretro.git
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166 lines
3.3 KiB
C++
166 lines
3.3 KiB
C++
/* Mednafen - Multi-system Emulator
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*
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* This program 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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* This program 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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#ifndef __MDFN_OKIADPCM_H
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#define __MDFN_OKIADPCM_H
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// PC-FX ADPCM decoder not finished!
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typedef enum
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{
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OKIADPCM_MSM5205 = 0,
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OKIADPCM_MSM5218 = 1,
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OKIADPCM_COUNT
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} OKIADPCM_Chip;
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extern const int OKIADPCM_StepSizes[49];
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extern const int OKIADPCM_StepIndexDeltas[16];
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extern const int32 OKIADPCM_DeltaTable[49][16];
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template <OKIADPCM_Chip CHIP_TYPE>
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class OKIADPCM_Decoder
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{
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public:
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OKIADPCM_Decoder()
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{
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assert(CHIP_TYPE < OKIADPCM_COUNT);
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CurSample = 0x0800;
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StepSizeIndex = 0;
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}
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~OKIADPCM_Decoder()
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{
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}
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INLINE uint16 GetSample(void)
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{
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return(CurSample);
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}
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INLINE void SetSample(uint16 new_sample)
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{
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assert(new_sample <= 0xFFF);
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CurSample = new_sample;
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}
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INLINE uint8 GetSSI(void)
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{
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return(StepSizeIndex);
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}
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INLINE void SetSSI(uint8 new_ssi)
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{
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assert(new_ssi <= 48);
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StepSizeIndex = new_ssi;
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}
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// DecodeDelta returns the coded delta for the given nibble and (previous) predictor.
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// It will not wrap nor saturate the returned value, and CurSample is not updated.
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INLINE int32 DecodeDelta(const uint8 nibble)
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{
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int32 ret = OKIADPCM_DeltaTable[StepSizeIndex][nibble];
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StepSizeIndex += OKIADPCM_StepIndexDeltas[nibble];
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if(StepSizeIndex < 0)
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StepSizeIndex = 0;
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if(StepSizeIndex > 48)
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StepSizeIndex = 48;
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return(ret);
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}
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// This function will return the full 12-bits, it's up to the caller to
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// truncate as necessary(MSM5205 only has a 10-bit D/A, MSM5218 has a 12-bit D/A)
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INLINE uint16 Decode(const uint8 nibble)
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{
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CurSample += DecodeDelta(nibble);
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if(CHIP_TYPE == OKIADPCM_MSM5205)
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{
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CurSample &= 0xFFF;
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}
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else if(CHIP_TYPE == OKIADPCM_MSM5218)
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{
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if(CurSample > 0xFFF)
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CurSample = 0xFFF;
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if(CurSample < 0)
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CurSample = 0;
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}
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return(CurSample);
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}
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private:
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int32 CurSample;
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int32 StepSizeIndex;
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};
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template <OKIADPCM_Chip CHIP_TYPE>
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class OKIADPCM_Encoder
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{
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public:
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OKIADPCM_Encoder()
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{
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Accum = 0x800;
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StepSizeIndex = 0;
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}
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~OKIADPCM_Encoder()
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{
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}
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uint8 EncodeSample(uint16 in_sample)
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{
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uint8 nibble = 0;
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int32 sample_delta = in_sample - Accum;
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int piece;
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piece = (abs(sample_delta) * 4 / OKIADPCM_StepSizes[StepSizeIndex]);
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if(piece > 0x7)
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piece = 0x7;
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nibble = ((uint32)(sample_delta >> 31) & 0x8) | piece;
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// Update Accum and StepSizeIndex!
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Accum += OKIADPCM_DeltaTable[StepSizeIndex][nibble];
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StepSizeIndex += OKIADPCM_StepIndexDeltas[nibble];
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if(Accum > 0xFFF) Accum = 0xFFF;
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if(Accum < 0) Accum = 0;
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if(StepSizeIndex < 0)
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StepSizeIndex = 0;
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if(StepSizeIndex > 48)
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StepSizeIndex = 48;
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return(nibble);
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}
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private:
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int32 Accum;
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int32 StepSizeIndex;
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OKIADPCM_Chip ChipType;
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};
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#endif
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