BizHawk/BizHawk.Emulation.Cores/Consoles/PC Engine/VCE.cs

145 lines
3.6 KiB
C#

using System;
using System.Globalization;
using System.IO;
using BizHawk.Common;
namespace BizHawk.Emulation.Cores.PCEngine
{
// HuC6260 Video Color Encoder
public sealed class VCE
{
public ushort VceAddress;
public ushort[] VceData = new ushort[512];
public int[] Palette = new int[512];
public byte CR;
public int NumberOfScanlines { get { return ((CR & 4) != 0) ? 263 : 262; } }
public int DotClock
{
get
{
int clock = CR & 3;
if (clock == 3)
clock = 2;
return clock;
}
}
// guess the dot clock affects wait states in combination with the dot with regs.
// We dont currently emulate wait states, probably will have to eventually...
// Note: To keep the VCE class from needing a reference to the CPU, the 1-cycle access
// penalty for the VCE is handled by the memory mappers.
// One day I guess I could create an ICpu with a StealCycles method...
public void WriteVCE(int port, byte value)
{
port &= 0x07;
switch (port)
{
case 0: // Control Port
CR = value;
break;
case 2: // Address LSB
VceAddress &= 0xFF00;
VceAddress |= value;
break;
case 3: // Address MSB
VceAddress &= 0x00FF;
VceAddress |= (ushort)(value << 8);
VceAddress &= 0x01FF;
break;
case 4: // Data LSB
VceData[VceAddress] &= 0xFF00;
VceData[VceAddress] |= value;
PrecomputePalette(VceAddress);
break;
case 5: // Data MSB
VceData[VceAddress] &= 0x00FF;
VceData[VceAddress] |= (ushort)(value << 8);
PrecomputePalette(VceAddress);
VceAddress++;
VceAddress &= 0x1FF;
break;
}
}
public byte ReadVCE(int port)
{
port &= 0x07;
switch (port)
{
case 4: // Data LSB
return (byte)(VceData[VceAddress] & 0xFF);
case 5: // Data MSB
byte value = (byte)((VceData[VceAddress] >> 8) | 0xFE);
VceAddress++;
VceAddress &= 0x1FF;
return value;
default: return 0xFF;
}
}
static readonly byte[] PalConvert = { 0, 36, 72, 109, 145, 182, 218, 255 };
public void PrecomputePalette(int slot)
{
byte r = PalConvert[(VceData[slot] >> 3) & 7];
byte g = PalConvert[(VceData[slot] >> 6) & 7];
byte b = PalConvert[VceData[slot] & 7];
Palette[slot] = Colors.ARGB(r, g, b);
}
public void SaveStateText(TextWriter writer)
{
writer.WriteLine("[VCE]");
writer.WriteLine("VceAddress {0:X4}", VceAddress);
writer.WriteLine("CR {0}", CR);
writer.Write("VceData ");
VceData.SaveAsHex(writer);
writer.WriteLine("[/VCE]\n");
}
public void LoadStateText(TextReader reader)
{
while (true)
{
string[] args = reader.ReadLine().Split(' ');
if (args[0].Trim() == "") continue;
if (args[0] == "[/VCE]") break;
if (args[0] == "VceAddress")
VceAddress = ushort.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "CR")
CR = byte.Parse(args[1]);
else if (args[0] == "VceData")
VceData.ReadFromHex(args[1]);
else
Console.WriteLine("Skipping unrecognized identifier " + args[0]);
}
for (int i = 0; i < VceData.Length; i++)
PrecomputePalette(i);
}
public void SaveStateBinary(BinaryWriter writer)
{
writer.Write(VceAddress);
writer.Write(CR);
for (int i = 0; i < VceData.Length; i++)
writer.Write(VceData[i]);
}
public void LoadStateBinary(BinaryReader reader)
{
VceAddress = reader.ReadUInt16();
CR = reader.ReadByte();
for (int i = 0; i < VceData.Length; i++)
{
VceData[i] = reader.ReadUInt16();
PrecomputePalette(i);
}
}
}
}