interrupt.h

/*
 * This file is part of libsidplayfp, a SID player engine.
 *
 * Copyright 2011-2020 Leandro Nini <drfiemost@users.sourceforge.net>
 * 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 INTERRUPT_H
#define INTERRUPT_H
 
#include "Event.h"
#include "EventScheduler.h"
#include "EventCallback.h"
 
#include <stdint.h>
 
#include "sidcxx11.h"
 
namespace libsidplayfp
{
 
class MOS652X;
 
class InterruptSource
{
public:
    enum
    {
        INTERRUPT_NONE         = 0,      
        INTERRUPT_UNDERFLOW_A  = 1 << 0, 
        INTERRUPT_UNDERFLOW_B  = 1 << 1, 
        INTERRUPT_ALARM        = 1 << 2, 
        INTERRUPT_SP           = 1 << 3, 
        INTERRUPT_FLAG         = 1 << 4, 
        INTERRUPT_REQUEST      = 1 << 7  
    };
 
private:
    MOS652X &parent;
 
protected:
    EventScheduler &eventScheduler;
 
    event_clock_t last_clear = 0;
    event_clock_t last_set = 0;
 
    uint8_t icr = 0;
 
    uint8_t idr = 0;
 
    uint8_t idrTemp = 0;
 
    bool scheduled = false;
 
    bool asserted = false;
 
private:
    EventCallback<InterruptSource> interruptEvent;
 
    EventCallback<InterruptSource> updateIdrEvent;
 
    EventCallback<InterruptSource> setIrqEvent;
 
    EventCallback<InterruptSource> clearIrqEvent;
 
protected:
    inline bool interruptTriggered() const { return idr & INTERRUPT_REQUEST; }
 
    inline bool interruptMasked(uint8_t interruptMask) const
    {
        return ((interruptMask != INTERRUPT_NONE) ? interruptMask : idr) & icr;
    }
 
    virtual void triggerInterrupt() =0;
 
    inline bool ack0() const { return eventScheduler.getTime(EVENT_CLOCK_PHI2) == (last_clear+1); }
    inline bool write0() const { return eventScheduler.getTime(EVENT_CLOCK_PHI2) == (last_set+1); }
 
    void interrupt();
 
    void updateIdr();
 
    void setIrq();
 
    void clearIrq();
 
protected:
    InterruptSource(EventScheduler &scheduler, MOS652X &parent) :
        parent(parent),
        eventScheduler(scheduler),
        interruptEvent("CIA Interrupt", *this, &InterruptSource::interrupt),
        updateIdrEvent("CIA update ICR", *this, &InterruptSource::updateIdr),
        setIrqEvent("CIA set IRQ", *this, &InterruptSource::setIrq),
        clearIrqEvent("CIA clear IRQ", *this, &InterruptSource::clearIrq)
    {}
 
    void schedule(int delay)
    {
        if (!scheduled)
        {
            eventScheduler.schedule(interruptEvent, delay, EVENT_CLOCK_PHI1);
            scheduled = true;
        }
    }
 
    void scheduleIrq()
    {
        eventScheduler.schedule(setIrqEvent, 1, EVENT_CLOCK_PHI1);
    }
 
    bool isTriggered(uint8_t interruptMask);
 
public:
    virtual ~InterruptSource() = default;
 
    virtual void trigger(uint8_t interruptMask) =0;
 
    virtual uint8_t clear();
 
    virtual void reset()
    {
        last_clear = 0;
        last_set = 0;
 
        icr = 0;
        idr = 0;
 
        eventScheduler.cancel(updateIdrEvent);
        eventScheduler.cancel(setIrqEvent);
        eventScheduler.cancel(clearIrqEvent);
        eventScheduler.cancel(interruptEvent);
        scheduled = false;
 
        asserted = false;
    }
 
    void set(uint8_t interruptMask);
};
 
}
 
#endif // INTERRUPT_H