mmu.h

/*
 * This file is part of libsidplayfp, a SID player engine.
 *
 * Copyright 2011-2021 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 MMU_H
#define MMU_H
 
#include "sidendian.h"
#include "sidmemory.h"
#include "EventScheduler.h"
 
#include "Banks/pla.h"
#include "Banks/SystemRAMBank.h"
#include "Banks/SystemROMBanks.h"
#include "Banks/ZeroRAMBank.h"
 
#include "sidcxx11.h"
 
#include <cstdint>
#include <cstring>
 
namespace libsidplayfp
{
 
class Bank;
class IOBank;

class MMU final : public PLA, public sidmemory
{
private:
    EventScheduler &eventScheduler;


    bool loram = false;
    bool hiram = false;
    bool charen = false;
 
    friend uint8_t readIO(MMU &self, uint_least16_t addr);
    using ReadFunc = uint8_t (*)(MMU &self, uint_least16_t addr);

    ReadFunc cpuReadMap[16];

    Bank* cpuWriteMap[16];

    IOBank* ioBank;

    KernalRomBank kernalRomBank;

    BasicRomBank basicRomBank;

    CharacterRomBank characterRomBank;

    SystemRAMBank ramBank;

    ZeroRAMBank zeroRAMBank;

    mutable unsigned int seed = 3686734;
 
private:
    void setCpuPort(uint8_t state) override;
    uint8_t getLastReadByte() const override;
    event_clock_t getPhi2Time() const override { return eventScheduler.getTime(EVENT_CLOCK_PHI2); }
 
    void updateMappingPHI2();
 
public:
    MMU(EventScheduler &scheduler, IOBank* ioBank);
 
    void reset();
 
    // ROM banks methods
    void setKernal(const uint8_t* rom) override { kernalRomBank.set(rom); }
    void setBasic(const uint8_t* rom) override { basicRomBank.set(rom); }
    void setChargen(const uint8_t* rom) override { characterRomBank.set(rom); }
 
    // RAM access methods
    uint8_t readMemByte(uint_least16_t addr) override { return ramBank.peek(addr); }
    uint_least16_t readMemWord(uint_least16_t addr) override { return endian_little16(ramBank.ram+addr); }
 
    void writeMemByte(uint_least16_t addr, uint8_t value) override { ramBank.poke(addr, value); }
    void writeMemWord(uint_least16_t addr, uint_least16_t value) override { endian_little16(ramBank.ram+addr, value); }
 
    void fillRam(uint_least16_t start, uint8_t value, unsigned int size) override
    {
        std::memset(ramBank.ram+start, value, size);
    }
    void fillRam(uint_least16_t start, const uint8_t* source, unsigned int size) override
    {
        std::memcpy(ramBank.ram+start, source, size);
    }
 
    // SID specific hacks
    void installResetHook(uint_least16_t addr) override { kernalRomBank.installResetHook(addr); }
 
    void installBasicTrap(uint_least16_t addr) override { basicRomBank.installTrap(addr); }
 
    void setBasicSubtune(uint8_t tune) override { basicRomBank.setSubtune(tune); }

    uint8_t cpuRead(uint_least16_t addr) { return (cpuReadMap[addr >> 12])(*this, addr); }

    void cpuWrite(uint_least16_t addr, uint8_t data) { cpuWriteMap[addr >> 12]->poke(addr, data); }
};
 
}
 
#endif