131 lines
4.2 KiB
C#
131 lines
4.2 KiB
C#
using System;
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using System.Runtime.CompilerServices;
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namespace AxibugEmuOnline.Client.UNES
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{
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partial class PPU
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{
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private readonly byte[] _oam = new byte[0x100];
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private readonly byte[] _vRam = new byte[0x2000];
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private readonly byte[] _paletteRAM = new byte[0x20];
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private static readonly uint[][] _vRamMirrorLookup =
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{
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new uint[]{0, 0, 1, 1}, // H
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new uint[]{0, 1, 0, 1}, // V
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new uint[]{0, 1, 2, 3}, // All
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new uint[]{0, 0, 0, 0}, // Upper
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new uint[]{1, 1, 1, 1}, // Lower
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};
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private int _lastWrittenRegister;
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public void WriteRegister(uint reg, byte val)
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{
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reg &= 0xF;
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_lastWrittenRegister = val & 0xFF;
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switch (reg)
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{
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case 0x0000:
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PPUCTRL = val;
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return;
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case 0x0001:
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PPUMASK = val;
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return;
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case 0x0002: return;
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case 0x0003:
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OAMADDR = val;
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return;
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case 0x0004:
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OAMDATA = val;
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return;
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case 0x005:
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PPUSCROLL = val;
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return;
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case 0x0006:
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PPUADDR = val;
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return;
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case 0x0007:
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PPUDATA = val;
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return;
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}
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throw new NotImplementedException($"{reg:X4} = {val:X2}");
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}
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public byte ReadRegister(uint reg)
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{
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reg &= 0xF;
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switch (reg)
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{
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case 0x0000: return (byte)_lastWrittenRegister;
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case 0x0001: return (byte)_lastWrittenRegister;
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case 0x0002:
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return (byte)PPUSTATUS;
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case 0x0003:
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return (byte)OAMADDR;
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case 0x0004:
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return (byte)OAMDATA;
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case 0x0005: return (byte)_lastWrittenRegister;
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case 0x0006: return (byte)_lastWrittenRegister;
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case 0x0007:
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return (byte)PPUDATA;
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}
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throw new NotImplementedException(reg.ToString("X2"));
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public uint GetVRamMirror(long address)
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{
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long entry;
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var table = Math.DivRem(address - 0x2000, 0x400, out entry);
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return _vRamMirrorLookup[(int)_emulator.Cartridge.MirroringMode][table] * 0x400 + (uint)entry;
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}
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protected override void InitializeMemoryMap()
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{
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base.InitializeMemoryMap();
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MapReadHandler(0x2000, 0x2FFF, address => _vRam[GetVRamMirror(address)]);
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MapReadHandler(0x3000, 0x3EFF, address => _vRam[GetVRamMirror(address - 0x1000)]);
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MapReadHandler(0x3F00, 0x3FFF, address =>
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{
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if (address == 0x3F10 || address == 0x3F14 || address == 0x3F18 || address == 0x3F0C)
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{
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address -= 0x10;
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}
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return _paletteRAM[(address - 0x3F00) & 0x1F];
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});
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MapWriteHandler(0x2000, 0x2FFF, (address, val) => _vRam[GetVRamMirror(address)] = val);
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MapWriteHandler(0x3000, 0x3EFF, (address, val) => _vRam[GetVRamMirror(address - 0x1000)] = val);
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MapWriteHandler(0x3F00, 0x3FFF, (address, val) =>
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{
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if (address == 0x3F10 || address == 0x3F14 || address == 0x3F18 || address == 0x3F0C)
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{
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address -= 0x10;
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}
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_paletteRAM[(address - 0x3F00) & 0x1F] = val;
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});
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_emulator.Mapper.InitializeMemoryMap(this);
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}
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public void PerformDMA(uint from)
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{
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//Console.WriteLine("OAM DMA");
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from <<= 8;
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for (uint i = 0; i <= 0xFF; i++)
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{
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_oam[F.OAMAddress] = (byte)_emulator.CPU.ReadByte(from);
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from++;
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F.OAMAddress++;
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}
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_emulator.CPU.Cycle += 513 + _emulator.CPU.Cycle % 2;
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}
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}
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}
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