DMA.hpp

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//
// Created by anonymus-raccoon on 5/26/20.
//
 
#pragma once
 
#include "Memory/MemoryBus.hpp"
#include "Models/Ints.hpp"
#include <cstdint>
#include <memory>
 
#ifdef DEBUGGER_ENABLED
#include "Debugger/RegisterViewer.hpp"
#endif
 
namespace ComSquare::CPU
{
    class DMA
    {
    public:
        enum DMAMode
        {
            OneToOne = 0b000,
            TwoToTwo = 0b001,
            TwoToOne = 0b010,
            FourToTwo = 0b011,
            FourToFour = 0b100,
            TwoToTwoBis = 0b101,
            TwoToOneBis = 0b110,
            FourToTwoBis = 0b111
        };
 
        enum Direction
        {
            AtoB,
            BtoA
        };
 
    private:
        unsigned _writeOneByte(uint24_t aAddress, uint24_t bAddress);
        [[nodiscard]] int _getModeOffset(int index) const;
 
        union
        {
            struct {
                DMAMode mode : 3;
                bool fixed : 1;
                bool increment : 1;
                bool _ : 2;
                Direction direction : 1;
            };
            uint8_t raw;
        } _controlRegister {};
 
        uint8_t _port {};
 
        union
        {
            uint8_t bytes[3];
            struct {
                uint16_t page;
                uint8_t bank;
            };
            uint24_t raw : 24;
        } _aAddress {};
 
        union
        {
            uint8_t bytes[2];
            uint16_t raw;
        } _count {};
 
        Memory::IMemoryBus &_bus;
 
    public:
        [[nodiscard]] inline Memory::IMemoryBus &getBus()
        {
            return this->_bus;
        }
        void setBus(Memory::IMemoryBus &bus);
 
        bool enabled;
 
        [[nodiscard]] uint8_t read(uint8_t addr) const;
 
        void write(uint8_t addr, uint8_t data);
 
        unsigned run(unsigned cycles);
 
        explicit DMA(Memory::IMemoryBus &bus);
        DMA(const DMA &) = default;
        DMA &operator=(const DMA &) = delete;
        ~DMA() = default;
 
#ifdef DEBUGGER_ENABLED
        friend Debugger::RegisterViewer;
#endif
    };
}// namespace ComSquare::CPU