dosbox.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
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/*
 * Based on OPL emulation code of DOSBox
 * Copyright (C) 2002-2009  The DOSBox Team
 * Licensed under GPLv2+
 * http://www.dosbox.com
 */

#ifndef AUDIO_SOFTSYNTH_OPL_DOSBOX_H
#define AUDIO_SOFTSYNTH_OPL_DOSBOX_H

#ifndef DISABLE_DOSBOX_OPL

#include "audio/fmopl.h"

namespace OPL {
namespace DOSBox {

struct Timer {
    double startTime;
    double delay;
    bool enabled, overflow, masked;
    uint8 counter;

    Timer();

    //Call update before making any further changes
    void update(double time);

    //On a reset make sure the start is in sync with the next cycle
    void reset(double time);

    void stop();

    void start(double time, int scale);
};

struct Chip {
    //Last selected register
    Timer timer[2];
    //Check for it being a write to the timer
    bool write(uint32 addr, uint8 val);
    //Read the current timer state, will use current double
    uint8 read();
};

namespace DBOPL {
struct Chip;
} // end of namespace DBOPL

class OPL : public ::OPL::OPL, public Audio::EmulatedChip {
private:
    Config::OplType _type;
    uint _rate;

    DBOPL::Chip *_emulator;
    ::OPL::DOSBox::Chip _chip[2];
    union {
        uint16 normal;
        uint8 dual[2];
    } _reg;

    void free();
    void dualWrite(uint8 index, uint8 reg, uint8 val);
public:
    OPL(Config::OplType type);
    ~OPL();

    bool init();
    void reset();

    void write(int a, int v);

    void writeReg(int r, int v);

    bool isStereo() const { return _type != Config::kOpl2; }

protected:
    void generateSamples(int16 *buffer, int length);
};

} // End of namespace DOSBox
} // End of namespace OPL

#endif // !DISABLE_DOSBOX_OPL

#endif