194 lines
4.4 KiB
C#
194 lines
4.4 KiB
C#
using System;
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using BizHawk.Common.BufferExtensions;
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using BizHawk.Emulation.Common;
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// X = don't care
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/*
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1. TIA 0000 00XX 0000 0000 - 0000 00XX 0001 1111
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2. MARIA 0000 00XX 0010 0000 - 0000 00XX 0011 1111
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3. 6532 0000 0010 1000 0000 - 0000 0010 1111 1111
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PORTS
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4. 6532 0000 010X 1000 0000 - 0000 010X 1111 1111
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RAM(DON'T USE)
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5. RAM 0001 1000 0000 0000 - 0010 0111 1111 1111
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6. RAM 00X0 000A 0100 0000 - 00X0 000A 1111 1111
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SHADOW
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7. RAM 001X X000 0000 0000 - 001X X111 1111 1111
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*/
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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, "System Bus");
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if ((addr & 0xFCE0) == 0)
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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)
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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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slow_access = true;
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return tia.ReadMemory((ushort)(addr & 0x1F), false);
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}
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}
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else if ((addr & 0xFCE0) == 0x20)
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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 & 0x1F];
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}
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else
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{
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return 0x80; // TODO: What if Maria is off?
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}
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}
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else if ((addr & 0xFF80) == 0x280)
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{
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slow_access = true;
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return m6532.ReadMemory(addr, false);
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}
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else if ((addr & 0xFE80) == 0x480)
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{
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slow_access = true;
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return RAM_6532[addr & 0x7F];
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}
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else if ((addr >= 0x1800) && (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 >= 0x40) && (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 >= 0x140) && (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 >= 0x2800) && (addr < 0x3000))
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{
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return RAM[(addr & 0x7FF) + 0x800];
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}
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else if ((addr >= 0x3000) && (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 if ((addr >= 0x400) && (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) && (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
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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, "System Bus");
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if ((addr & 0xFCE0) == 0)
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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)
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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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slow_access = true;
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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 & 0xFCE0) == 0x20)
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{
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if ((A7800_control_register & 0x2) > 0)
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{
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// register 8 is read only and controlled by Maria
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var temp = addr & 0x1F;
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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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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(maria.scanline);
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*/
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}
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else
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{
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// TODO: What if Maria is off?
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}
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}
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else if ((addr & 0xFF80) == 0x280)
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{
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slow_access = true;
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m6532.WriteMemory(addr, value);
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}
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else if ((addr & 0xFE80) == 0x480)
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{
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slow_access = true;
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RAM_6532[addr & 0x7F] = value;
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}
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else if ((addr >= 0x1800) && (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 >= 0x40) && (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 >= 0x140) && (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 >= 0x2800) && (addr < 0x3000))
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{
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RAM[(addr & 0x7FF) + 0x800] = value;
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}
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else if ((addr >= 0x3000) && (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 if ((addr >= 0x400) && (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) && (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
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{
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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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