187 lines
3.9 KiB
C#
187 lines
3.9 KiB
C#
using System;
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using BizHawk.Common.BufferExtensions;
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using BizHawk.Emulation.Common;
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namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
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{
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public partial class A7800Hawk
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{
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public byte ReadMemory(ushort addr)
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{
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MemoryCallbacks.CallReads(addr);
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if (addr < 0x0400) {
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if ((addr & 0xFF) < 0x20)
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{
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// return TIA registers or control register if it is still unlocked
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if ((A7800_control_register & 0x1) == 0 && (addr < 0x20))
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{
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return 0xFF; // TODO: what to return here?
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}
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else
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{
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return TIA_regs[addr & 0x1F]; // TODO: what to return here?
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}
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}
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else if ((addr & 0xFF) < 0x40)
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{
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if ((A7800_control_register & 0x2) > 0)
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{
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return Maria_regs[(addr & 0x3F) - 0x20];
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}
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else
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{
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return 0xFF;
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}
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}
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else if (addr < 0x100)
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{
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// RAM block 0
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return RAM[addr - 0x40 + 0x840];
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}
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else if (addr < 0x200)
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{
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// RAM block 1
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return RAM[addr - 0x140 + 0x940];
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}
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else if (addr < 0x300)
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{
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if (addr > 0x280)
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return regs_6532[addr - 0x280];
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else
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return 0xFF; // unclear what is mapped from 0x240 - 0x280
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}
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else
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{
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return 0xFF; // what is mapped here?
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}
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}
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else if (addr < 0x480)
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{
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// cartridge space available
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return mapper.ReadMemory(addr);
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}
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else if (addr < 0x500)
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{
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// this is where RAM for the 6532 resides for use in 2600 mode
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return 0xFF;
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}
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else if (addr < 0x1800)
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{
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// cartridge space available
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return mapper.ReadMemory(addr);
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}
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else if (addr < 0x2800)
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{
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return RAM[addr - 0x1800];
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}
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else if (addr < 0x4000)
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{
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// could be either RAM mirror or ROM
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return mapper.ReadMemory(addr);
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}
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else
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{
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return mapper.ReadMemory(addr);
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}
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}
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public void WriteMemory(ushort addr, byte value)
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{
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MemoryCallbacks.CallWrites(addr);
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if (addr < 0x0400)
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{
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if ((addr & 0xFF) < 0x20)
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{
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// return TIA registers or control register if it is still unlocked
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if ((A7800_control_register & 0x1) == 0 && (addr < 0x20))
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{
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A7800_control_register = value;
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}
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else
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{
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TIA_regs[addr & 0x1F] = value;
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tia.WriteMemory((ushort)(addr & 0x1F), value, false);
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}
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}
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else if ((addr & 0xFF) < 0x40)
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{
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if ((A7800_control_register & 0x2) > 0)
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{
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var temp = (addr & 0x3F) - 0x20;
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// register 8 is read only and controlled by Maria
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if (temp != 8)
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Maria_regs[temp] = value;
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if (temp==4) // WSYNC
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cpu.RDY = false;
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/*
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Console.WriteLine("Maria Regs: ");
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for (int i = 0; i < 0x20; i++)
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{
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Console.Write(Maria_regs[i]);
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Console.Write(" ");
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}
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Console.WriteLine(" ");
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*/
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}
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}
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else if (addr < 0x100)
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{
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// RAM block 0
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RAM[addr - 0x40 + 0x840] = value;
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}
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else if (addr < 0x200)
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{
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// RAM block 1
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RAM[addr - 0x140 + 0x940] = value;
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}
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else if (addr < 0x300)
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{
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if (addr > 0x280)
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regs_6532[addr - 0x280] = value;
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}
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else
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{
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// what is mapped here?
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}
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}
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else if (addr < 0x480)
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{
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// cartridge space available
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mapper.WriteMemory(addr, value);
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}
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else if (addr < 0x500)
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{
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// this is where RAM for the 6532 resides for use in 2600 mode
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// is it accessible in 7800 mode?
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}
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else if (addr < 0x1800)
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{
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// cartridge space available
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mapper.WriteMemory(addr, value);
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}
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else if (addr < 0x2800)
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{
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RAM[addr - 0x1800] = value;
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}
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else if (addr < 0x4000)
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{
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// could be either RAM mirror or ROM
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mapper.WriteMemory(addr, value);
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}
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else
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{
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// cartridge and other OPSYS
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mapper.WriteMemory(addr, value);
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}
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}
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}
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}
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