ay8912.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
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 */

#ifndef AUDIO_SOFTSYNTH_AY8912_H
#define AUDIO_SOFTSYNTH_AY8912_H

#include "audio/chip.h"
#include "common/mutex.h"

namespace Audio {

class AY8912Stream : public EmulatedChip {
public:
    enum ChipType {
        AY_TYPE_AY,
        AY_TYPE_YM
    };

    enum StereoType {
        AY_MONO = 0,
        AY_ABC,
        AY_ACB,
        AY_BAC,
        AY_BCA,
        AY_CAB,
        AY_CBA
    };

    AY8912Stream(int rate = 44100, int chipFreq = 1773400);
    ~AY8912Stream();

    // AudioStream interface
    int readBuffer(int16 *buffer, const int numSamples) override;
    bool isStereo() const override { return true; }
    bool endOfData() const override { return false; }
    bool endOfStream() const override { return false; }
    int getRate() const override { return _rate; }

    void setReg(int reg, unsigned char value);
    void setRegs(const unsigned char *regs);

    AudioStream *toAudioStream() { return this; }

protected:
    // EmulatedChip interface
    void generateSamples(int16 *buffer, int numSamples) override;

private:
    struct RegData {
        int tone_a;
        int tone_b;
        int tone_c;
        int noise;
        int R7_tone_a;
        int R7_tone_b;
        int R7_tone_c;
        int R7_noise_a;
        int R7_noise_b;
        int R7_noise_c;
        int vol_a;
        int vol_b;
        int vol_c;
        int env_a;
        int env_b;
        int env_c;
        int env_freq;
        int env_style;
    };

    Common::Mutex _mutex;
    int _rate;
    int _chipFreq;

    // Emulator state
    int _table[32];
    int _eq[6];
    RegData _regs;

    int _bit_a, _bit_b, _bit_c, _bit_n;
    int _cnt_a, _cnt_b, _cnt_c, _cnt_n, _cnt_e;
    int _chipTactsPerOutcount;
    int _ampGlobal;
    int _vols[6][32];
    int _envPos;
    unsigned int _curSeed;

    void prepareGeneration();
    static void genEnv();
    static bool _envGenInit;
    static int _envelope[16][128];
};

} // End of namespace Audio

#endif // AUDIO_SOFTSYNTH_AY8912_H