69 lines
3.3 KiB
C#
69 lines
3.3 KiB
C#
namespace BizHawk.Emulation.Consoles.TurboGrafx
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{
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public partial class PCEngine
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{
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// The SuperGrafx has 32K of RAM and a different port configuration to allow
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// I/O access to VDC1, VDC2, and the VPC.
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byte ReadMemorySGX(int addr)
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{
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if (addr < 0xFFFFF) // read ROM
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return RomData[addr % RomLength];
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if (addr >= 0x1F0000 && addr < 0x1F8000) // read RAM
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return Ram[addr & 0x7FFF];
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if (addr >= 0x1FE000) // hardware page.
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{
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if (addr < 0x1FE400)
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{
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addr &= 0x1F;
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if (addr <= 0x07) return VDC1.ReadVDC(addr);
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if (addr <= 0x0F) return VPC.ReadVPC(addr);
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if (addr <= 0x17) return VDC2.ReadVDC(addr);
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return 0xFF;
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}
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if (addr < 0x1FE800) { Cpu.PendingCycles--; return VCE.ReadVCE(addr); }
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if (addr < 0x1FEC00) return IOBuffer;
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if (addr < 0x1FF000) { IOBuffer = (byte)(Cpu.ReadTimerValue() | (IOBuffer & 0x80)); return IOBuffer; }
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if (addr >= 0x1FF000 &&
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addr < 0x1FF400) { IOBuffer = ReadInput(); return IOBuffer; }
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if ((addr & ~1) == 0x1FF400) return IOBuffer;
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if (addr == 0x1FF402) { IOBuffer = Cpu.IRQControlByte; return IOBuffer; }
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if (addr == 0x1FF403) { IOBuffer = (byte)(Cpu.ReadIrqStatus() | (IOBuffer & 0xF8)); return IOBuffer; }
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}
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Log.Error("MEM", "UNHANDLED READ: {0:X6}", addr);
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return 0xFF;
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}
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void WriteMemorySGX(int addr, byte value)
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{
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if (addr >= 0x1F0000 && addr < 0x1F8000) // write RAM.
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Ram[addr & 0x7FFF] = value;
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else if (addr >= 0x1FE000) // hardware page.
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{
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if (addr < 0x1FE400)
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{
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addr &= 0x1F;
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if (addr <= 0x07) VDC1.WriteVDC(addr, value);
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else if (addr <= 0x0F) VPC.WriteVPC(addr, value);
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else if (addr <= 0x17) VDC2.WriteVDC(addr, value);
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}
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else if (addr < 0x1FE800) { Cpu.PendingCycles--; VCE.WriteVCE(addr, value); }
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else if (addr < 0x1FEC00) { IOBuffer = value; PSG.WritePSG((byte)addr, value, Cpu.TotalExecutedCycles); }
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else if (addr == 0x1FEC00) { IOBuffer = value; Cpu.WriteTimer(value); }
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else if (addr == 0x1FEC01) { IOBuffer = value; Cpu.WriteTimerEnable(value); }
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else if (addr >= 0x1FF000 &&
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addr < 0x1FF400) { IOBuffer = value; WriteInput(value); }
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else if (addr == 0x1FF402) { IOBuffer = value; Cpu.WriteIrqControl(value); }
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else if (addr == 0x1FF403) { IOBuffer = value; Cpu.WriteIrqStatus(); }
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else Log.Error("MEM", "unhandled hardware write [{0:X6}] : {1:X2}", addr, value);
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}
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else
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Log.Error("MEM","UNHANDLED WRITE: {0:X6}:{1:X2}",addr,value);
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}
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}
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} |