255 lines
9.6 KiB
C#
255 lines
9.6 KiB
C#
using System;
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namespace BizHawk.Emulation.Consoles.Sega
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{
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partial class Genesis
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{
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public sbyte ReadByte(int address)
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{
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address &= 0x00FFFFFF;
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if (address < 0x200000)
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return (sbyte) RomData[address];
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if (address < 0x400000)
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{
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if (SaveRamEnabled && address >= SaveRamStartOffset && address < SaveRamEndOffset)
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{
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if (SaveRamEveryOtherByte)
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return (sbyte) SaveRAM[(address - SaveRamStartOffset) >> 1];
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else
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return (sbyte) SaveRAM[address - SaveRamStartOffset];
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}
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return (sbyte)RomData[address];
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}
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if (address >= 0xE00000)
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return (sbyte) Ram[address & 0xFFFF];
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if (address == 0xA11100) // Z80 BUS status
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{
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//Console.WriteLine("QUERY z80 bus status. 68000 can access? " + (M68000HasZ80Bus && Z80Reset == false));
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return (sbyte) (M68000HasZ80Bus && Z80Reset == false ? 0 : 1);
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}
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if (address >= 0xA10000 && address <= 0xA1001F)
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return (sbyte)ReadIO(address);
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if ((address & 0xFF0000) == 0xA00000)
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return (sbyte) ReadMemoryZ80((ushort) (address & 0x7FFF));
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if (address >= 0xC00000 && address < 0xC00010)
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{
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//Console.WriteLine("byte-reading the VDP. someone is probably stupid.");
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ushort value = VDP.ReadVdp(address & 0x0E);
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if ((address & 1) == 0) // read MSB
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return (sbyte) (value >> 8);
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return (sbyte) value; // read LSB
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}
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Console.WriteLine("UNHANDLED READB {0:X6}", address);
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return 0x7D;
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}
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public short ReadWord(int address)
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{
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address &= 0x00FFFFFF;
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int maskedAddr;
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if (address < 0x400000)
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return (short)((RomData[address] << 8) | RomData[address + 1]);
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if (address >= 0xE00000) // Work RAM
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{
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maskedAddr = address & 0xFFFE;
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return (short)((Ram[maskedAddr] << 8) | Ram[maskedAddr + 1]);
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}
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if (address >= 0xC00000 && address < 0xC00010)
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return (short) VDP.ReadVdp(address & 0x0E);
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if (address >= 0xA10000 && address <= 0xA1001F)
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return (sbyte)ReadIO(address);
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if (address == 0xA11100) // Z80 BUS status
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return (short)(M68000HasZ80Bus && Z80Reset == false ? 0x0000 : 0x0100);
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Console.WriteLine("UNHANDLED READW {0:X6}", address);
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return 0x7DCD;
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}
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public int ReadLong(int address)
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{
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address &= 0x00FFFFFF;
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int maskedAddr;
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if (address < 0x400000) // Cartridge ROM
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return (RomData[address] << 24) | (RomData[address + 1] << 16) | (RomData[address + 2] << 8) | RomData[address + 3];
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if (address >= 0xE00000) // Work RAM
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{
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maskedAddr = address & 0xFFFF;
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return (Ram[maskedAddr] << 24) | (Ram[maskedAddr + 1] << 16) | (Ram[maskedAddr + 2] << 8) | Ram[maskedAddr + 3];
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}
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if (address >= 0xC00000)
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{
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//Console.WriteLine("long-read from VDP");
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short msw = ReadWord(address);
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short msl = ReadWord(address + 2);
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return (msw << 16) | (ushort) msl;
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}
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// try to handle certain things separate if they need to be separate? otherwise handle as 2x readwords?
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{
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return ((ushort)ReadWord(address) | (ushort)(ReadWord(address + 2) << 16));
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}
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//if (address == 0xA10008) return 0; // FIXME HACK for tg-sync.
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//Console.WriteLine("UNHANDLED READL {0:X6}", address);
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//return 0x7DCDCDCD;
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}
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public void WriteByte(int address, sbyte value)
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{
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address &= 0x00FFFFFF;
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if (address >= 0xE00000) // Work RAM
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{
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//Console.WriteLine("MEM[{0:X4}] change from {1:X2} to {2:X2}", address & 0xFFFF, Ram[address & 0xFFFF], value);
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Ram[address & 0xFFFF] = (byte)value;
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return;
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}
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if ((address & 0xFF0000) == 0xA00000)
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{
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WriteMemoryZ80((ushort)(address & 0x7FFF), (byte)value);
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return;
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}
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if (address >= 0xA10000 && address <= 0xA1001F)
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{
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WriteIO(address, value);
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return;
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}
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if (address == 0xA11100)
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{
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M68000HasZ80Bus = (value & 1) != 0;
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//Console.WriteLine("68000 has the z80 bus: " + M68000HasZ80Bus);
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return;
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}
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if (address == 0xA11200) // Z80 RESET
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{
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Z80Reset = (value & 1) == 0;
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if (Z80Reset)
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SoundCPU.SoftReset();
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//Console.WriteLine("z80 reset: " + Z80Reset);
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return;
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}
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if (address >= 0xC00000 && address < 0xC00010)
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{
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// when writing to VDP in byte mode, the LSB is duplicated into the MSB
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VDP.WriteVdp(address & 0x1E, (ushort)((ushort)value | ((ushort)value << 8)));
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return;
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}
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if (address >= 0xC00011 && address <= 0xC00017 && (address & 1) != 0)
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{
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PSG.WritePsgData((byte) value, SoundCPU.TotalExecutedCycles);
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return;
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}
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if (SaveRamEnabled && address >= SaveRamStartOffset && address < SaveRamEndOffset)
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{
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if (SaveRamEveryOtherByte)
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SaveRAM[(address - SaveRamStartOffset) >> 1] = (byte) value;
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else
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SaveRAM[address - SaveRamStartOffset] = (byte) value;
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SaveRamModified = true;
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return;
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}
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if (EepromEnabled && (address == SclAddr || address == SdaInAddr))
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{
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WriteByteEeprom(address, (byte) value);
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return;
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}
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Console.WriteLine("UNHANDLED WRITEB {0:X6}:{1:X2}", address, value);
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}
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public void WriteWord(int address, short value)
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{
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address &= 0x00FFFFFF;
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if (address >= 0xE00000) // Work RAM
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{
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//Console.WriteLine("MEM[{0:X4}] change to {1:X4}", address & 0xFFFF, value);
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Ram[(address & 0xFFFF) + 0] = (byte)(value >> 8);
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Ram[(address & 0xFFFF) + 1] = (byte)value;
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return;
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}
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if (address >= 0xC00000)
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{
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switch (address & 0x1F)
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{
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case 0x00:
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case 0x02:
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VDP.WriteVdpData((ushort)value);
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return;
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case 0x04:
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case 0x06:
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VDP.WriteVdpControl((ushort)value);
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return;
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}
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}
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if (address == 0xA11100) // Z80 BUSREQ
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{
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M68000HasZ80Bus = (value & 0x100) != 0;
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//Console.WriteLine("68000 has the z80 bus: " + M68000HasZ80Bus);
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return;
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}
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if (address == 0xA11200) // Z80 RESET
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{
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Z80Reset = (value & 0x100) == 0;
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if (Z80Reset)
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SoundCPU.SoftReset();
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//Console.WriteLine("z80 reset: " + Z80Reset);
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return;
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}
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Console.WriteLine("UNHANDLED WRITEW {0:X6}:{1:X4}", address, value);
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}
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public void WriteLong(int address, int value)
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{
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address &= 0x00FFFFFF;
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if (address >= 0xE00000) // Work RAM
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{
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//Console.WriteLine("MEM[{0:X4}] change to {1:X8}", address & 0xFFFF, value);
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Ram[(address & 0xFFFF) + 0] = (byte)(value >> 24);
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Ram[(address & 0xFFFF) + 1] = (byte)(value >> 16);
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Ram[(address & 0xFFFF) + 2] = (byte)(value >> 8);
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Ram[(address & 0xFFFF) + 3] = (byte)value;
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return;
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}
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if (address >= 0xC00000)
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{
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WriteWord(address, (short)(value >> 16));
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WriteWord(address+2, (short)value);
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return;
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}
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Console.WriteLine("UNHANDLED WRITEL {0:X6}:{1:X8}", address, value);
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}
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// Mushashi interop test stuff. TODO kill this when we're ready to ditch musashi.
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public uint Read8(uint a) { /*Console.WriteLine("read8 {0:X}", a);*/ return (uint)ReadByte((int)a) & 0xFF; }
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public uint Read16(uint a) { /*Console.WriteLine("read16 {0:X}", a);*/ return (uint)ReadWord((int)a) & 0xFFFF; }
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public uint Read32(uint a) { /*Console.WriteLine("read32 {0:X}", a);*/ return (uint)ReadLong((int)a); }
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public void Write8(uint a, uint v) { /*Console.WriteLine("write8 {0:X}:{1:X2}", a, v);*/ WriteByte((int)a, (sbyte)v); }
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public void Write16(uint a, uint v) { /*Console.WriteLine("write16 {0:X}:{1:X4}", a, v);*/ WriteWord((int)a, (short)v); }
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public void Write32(uint a, uint v) { /*Console.WriteLine("write32 {0:X}:{1:X8}", a, v);*/ WriteLong((int)a, (int)v); }
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}
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}
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