124 lines
3.2 KiB
C#
124 lines
3.2 KiB
C#
using System;
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namespace Essgee.Emulation.Cartridges.Nintendo
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{
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public class MBC2Cartridge : IGameBoyCartridge
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{
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byte[] romData, ramData;
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bool hasBattery;
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byte romBank;
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bool ramEnable;
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public MBC2Cartridge(int romSize, int ramSize)
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{
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romData = new byte[romSize];
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ramData = new byte[ramSize];
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romBank = 1;
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ramEnable = false;
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hasBattery = false;
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}
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public void LoadRom(byte[] data)
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{
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Buffer.BlockCopy(data, 0, romData, 0, Math.Min(data.Length, romData.Length));
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}
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public void LoadRam(byte[] data)
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{
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Buffer.BlockCopy(data, 0, ramData, 0, Math.Min(data.Length, ramData.Length));
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}
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public byte[] GetRomData()
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{
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return romData;
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}
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public byte[] GetRamData()
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{
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return ramData;
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}
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public bool IsRamSaveNeeded()
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{
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return hasBattery;
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}
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public ushort GetLowerBound()
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{
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return 0x0000;
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}
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public ushort GetUpperBound()
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{
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return 0x7FFF;
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}
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public void SetCartridgeConfig(bool battery, bool rtc, bool rumble)
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{
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hasBattery = battery;
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}
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public void Step(int clockCyclesInStep)
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{
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/* Nothing to do */
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}
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public byte Read(ushort address)
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{
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if (address >= 0x0000 && address <= 0x3FFF)
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{
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return romData[address & 0x3FFF];
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}
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else if (address >= 0x4000 && address <= 0x7FFF)
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{
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return romData[(romBank << 14) | (address & 0x3FFF)];
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}
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else if (address >= 0xA000 && address <= 0xA1FF)
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{
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if (ramEnable)
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{
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var ramOffset = (address >> 1) & 0x00FF;
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var valueShift = (address & 0x01) << 2;
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return (byte)((ramData[ramOffset] >> valueShift) & 0x0F);
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}
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else
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return 0xFF;
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}
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else
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return 0xFF;
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}
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public void Write(ushort address, byte value)
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{
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if (address >= 0x0000 && address <= 0x1FFF)
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{
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if ((address & 0x0100) == 0)
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ramEnable = (value & 0x0F) == 0x0A;
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}
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else if (address >= 0x2000 && address <= 0x3FFF)
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{
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if ((address & 0x0100) != 0)
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{
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romBank = (byte)((romBank & 0xF0) | (value & 0x0F));
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romBank &= (byte)((romData.Length >> 14) - 1);
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if ((romBank & 0x0F) == 0x00) romBank |= 0x01;
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}
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}
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else if (address >= 0xA000 && address <= 0xA1FF)
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{
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if (ramEnable)
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{
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var ramOffset = (address >> 1) & 0x00FF;
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var valueShift = (address & 0x01) << 2;
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ramData[ramOffset] = (byte)((ramData[ramOffset] & (0x0F << (valueShift ^ 0x04))) | (value << valueShift));
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}
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}
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}
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}
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}
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