public ScanlineSprite Load(DataBus ppuBus, UInt16 patternTable, bool is8x16mode, uint scanline)
{
// 8x16 000j iiii iiis hsss
// 8x8 000p iiii iiii hsss
// p - patternTable
// i - patternIndex
// j - lowest nibble of pattern index
// h - high/low byte of pattern
// s - scanline - y
uint yIdx = scanline - Y;
if (FlipVer)
{
yIdx = (is8x16mode ? 15u : 7u) - yIdx;
}
UInt16 pattTable = patternTable;
byte pattIndex = PatternIndex;
if (is8x16mode)
{
// Set pattern table to lowest nibble of index and clear that bit
pattTable = (UInt16)((pattIndex & 0x01) << 12);
pattIndex = (byte)(pattIndex & 0xFE);
// Move the 4th bit to the 5th
yIdx = (yIdx & 0x07) | ((yIdx & 0x08) << 1);
}
UInt16 patternAddress = (UInt16)(pattTable | (pattIndex << 4) | (byte)yIdx);
LowPatternByte = ppuBus.Read(patternAddress);
HighPatternByte = ppuBus.Read((UInt16)(patternAddress | 0x0008));
Loaded = true;
return(this);
}
private void DrawPalettes()
{
Sprite bgTex = new Sprite(1, 1);
Pixel bgColor = BasePixels.Palette[_ppuBus.Read(0x3F00) & 0x3F];
bgTex.SetPixel(0, 0, bgColor);
DrawSprite(0, 250, bgTex, 4, (byte)Sprite.Flip.NONE);
for (int i = 0; i < 8; i++)
{
Sprite palTex = new Sprite(3, 1);
palTex.SetPixel(0, 0, BasePixels.Palette[_ppuBus.Read((UInt16)(0x3F00 + i * 4 + 1)) & 0x3F]);
palTex.SetPixel(1, 0, BasePixels.Palette[_ppuBus.Read((UInt16)(0x3F00 + i * 4 + 2)) & 0x3F]);
palTex.SetPixel(2, 0, BasePixels.Palette[_ppuBus.Read((UInt16)(0x3F00 + i * 4 + 3)) & 0x3F]);
DrawSprite(4 + i * 12, 250, palTex, 4, (byte)Sprite.Flip.NONE);
}
}
private List <string> Disassemble(int length)
{
UInt16 tmpPC = (UInt16)(_cpu.ProgramCounter - 1);
List <string> disassembly = new List <string>();
for (int i = 0; i < length; i++)
{
byte opCode = _cpuBus.Read(tmpPC++);
Instruction instruction = InstructionSet.InstuctionsByOpcode[opCode];
disassembly.Add(instruction.Name);
if (instruction.AddressMode == AddressModes.ABS)
{
tmpPC += 2;
}
if (instruction.AddressMode == AddressModes.ABX)
{
tmpPC += 2;
}
if (instruction.AddressMode == AddressModes.ABY)
{
tmpPC += 2;
}
if (instruction.AddressMode == AddressModes.IMM)
{
tmpPC += 1;
}
if (instruction.AddressMode == AddressModes.IMP)
{
tmpPC += 0;
}
if (instruction.AddressMode == AddressModes.IND)
{
tmpPC += 2;
}
if (instruction.AddressMode == AddressModes.IZX)
{
tmpPC += 1;
}
if (instruction.AddressMode == AddressModes.IZY)
{
tmpPC += 1;
}
if (instruction.AddressMode == AddressModes.REL)
{
tmpPC += 1;
}
if (instruction.AddressMode == AddressModes.ZP0)
{
tmpPC += 1;
}
if (instruction.AddressMode == AddressModes.ZPX)
{
tmpPC += 1;
}
if (instruction.AddressMode == AddressModes.ZPY)
{
tmpPC += 1;
}
}
return(disassembly);
}