85 lines
2.2 KiB
C#
85 lines
2.2 KiB
C#
using System;
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namespace BizHawk.Emulation.Cores.Sega.Genesis
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{
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partial class Genesis
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{
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private int BankRegion;
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public byte ReadMemoryZ80(ushort address)
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{
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if (address < 0x4000)
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{
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//Console.WriteLine("read z80 memory {0:X4}: {1:X2}",address, Z80Ram[address & 0x1FFF]);
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return Z80Ram[address & 0x1FFF];
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}
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if (address >= 0x4000 && address < 0x6000)
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{
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//Console.WriteLine(" === Z80 READS FM STATUS ===");
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return YM2612.ReadStatus(SoundCPU.TotalExecutedCycles); // TODO: more than 1 read port probably?
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}
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if (address >= 0x8000)
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{
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// 68000 Bank region
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return (byte)ReadByte(BankRegion | (address & 0x7FFF));
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}
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if (address <= 0x6100) // read from bank address register - returns FF
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return 0xFF;
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Console.WriteLine("UNHANDLED Z80 READ {0:X4}", address);
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return 0xCD;
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}
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public void WriteMemoryZ80(ushort address, byte value)
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{
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if (address < 0x4000)
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{
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//Console.WriteLine("write z80 memory {0:X4}: {1:X2}",address, value);
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Z80Ram[address & 0x1FFF] = value;
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return;
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}
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if (address >= 0x4000 && address < 0x6000)
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{
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//Console.WriteLine(" === Z80 WRITES YM2612 {0:X4}:{1:X2} ===",address, value);
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YM2612.Write(address & 3, value, SoundCPU.TotalExecutedCycles);
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return;
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}
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if (address < 0x6100)
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{
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BankRegion >>= 1;
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BankRegion |= (value & 1) << 23;
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BankRegion &= 0x00FF8000;
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//Console.WriteLine("Bank pointing at {0:X8}",BankRegion);
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return;
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}
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if (address >= 0x7F00 && address < 0x7F20)
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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 << 8) | 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 << 8) | value));
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return;
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case 0x11:
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case 0x13:
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case 0x15:
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case 0x17:
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PSG.WritePsgData(value, SoundCPU.TotalExecutedCycles);
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return;
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}
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}
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if (address >= 0x8000)
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{
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WriteByte(BankRegion | (address & 0x7FFF), (sbyte)value);
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return;
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}
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Console.WriteLine("UNHANDLED Z80 WRITE {0:X4}:{1:X2}", address, value);
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}
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}
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}
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