mos6526.h

/*
 * This file is part of libsidplayfp, a SID player engine.
 *
 * Copyright 2011-2018 Leandro Nini <drfiemost@users.sourceforge.net>
 * Copyright 2009-2014 VICE Project
 * Copyright 2007-2010 Antti Lankila
 * Copyright 2000 Simon White
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
 
#ifndef MOS6526_H
#define MOS6526_H
 
#include <memory>
 
#include <stdint.h>
 
#include "interrupt.h"
#include "timer.h"
#include "tod.h"
#include "SerialPort.h"
#include "EventScheduler.h"
 
#include "sidcxx11.h"
 
class EventContext;
 
namespace libsidplayfp
{
 
class MOS6526;
 
class TimerA final : public Timer
{
private:
    void underFlow() override;
 
    void serialPort() override;
 
public:
    TimerA(EventScheduler &scheduler, MOS6526 &parent) :
        Timer("CIA Timer A", scheduler, parent) {}
};
 
class TimerB final : public Timer
{
private:
    void underFlow() override;
 
public:
    TimerB(EventScheduler &scheduler, MOS6526 &parent) :
        Timer("CIA Timer B", scheduler, parent) {}
 
    void cascade()
    {
        // we pretend that we are CPU doing a write to ctrl register
        syncWithCpu();
        state |= CIAT_STEP;
        wakeUpAfterSyncWithCpu();
    }
 
    bool started() const { return (state & CIAT_CR_START) != 0; }
};
 
class InterruptSource8521 final : public InterruptSource
{
public:
    InterruptSource8521(EventScheduler &scheduler, MOS6526 &parent) :
        InterruptSource(scheduler, parent)
    {}
 
    void trigger(uint8_t interruptMask) override;
 
    uint8_t clear() override;
 
    void event() override
    {
        throw "8521 event called unexpectedly";
    }
};
 
class InterruptSource6526 final : public InterruptSource
{
private:
    event_clock_t last_clear;
 
    bool scheduled;
 
    bool tbBug;
 
private:
    void schedule()
    {
        if (!scheduled)
        {
            eventScheduler.schedule(*this, 1, EVENT_CLOCK_PHI1);
            scheduled = true;
        }
    }
 
public:
    InterruptSource6526(EventScheduler &scheduler, MOS6526 &parent) :
        InterruptSource(scheduler, parent),
        last_clear(0),
        scheduled(false),
        tbBug(false)
    {}
 
    void trigger(uint8_t interruptMask) override;
 
    uint8_t clear() override;
 
    void event() override;
 
    void reset() override;
};
 
class MOS6526
{
    friend class InterruptSource6526;
    friend class InterruptSource8521;
    friend class SerialPort;
    friend class TimerA;
    friend class TimerB;
    friend class Tod;
 
private:
    static const char *credit;
 
protected:
    EventScheduler &eventScheduler;
 
 
    uint8_t &pra, &prb, &ddra, &ddrb;
 
    uint8_t regs[0x10];
 
 
    TimerA timerA;
    TimerB timerB;
 
    std::unique_ptr<InterruptSource> interruptSource;
 
    Tod tod;
 
    SerialPort serialPort;
 
 
    EventCallback<MOS6526> bTickEvent;
 
private:
    void todInterrupt();
 
    void spInterrupt();
 
    void bTick();
 
    void underflowA();
 
    void underflowB();
 
    void handleSerialPort();
 
protected:
    MOS6526(EventScheduler &scheduler);
 
    virtual void interrupt(bool state) = 0;
 
    virtual void portA() {}
    virtual void portB() {}
 
    uint8_t read(uint_least8_t addr);
 
    void write(uint_least8_t addr, uint8_t data);
 
public:
    void setModel(bool newModel);
 
    virtual void reset();
 
    static const char *credits();
 
    void setDayOfTimeRate(unsigned int clock) { tod.setPeriod(clock); }
};
 
}
 
#endif // MOS6526_H