public void ComputeChecksum()
{
_writer.Seek(0, SeekOrigin.End);
long fileSize = _writer.Position;
byte[] allBytes = new byte[fileSize];
_writer.Seek(0, SeekOrigin.Begin);
_writer.Read(allBytes, 0, allBytes.Length);
uint checksum = 0;
for (int i = 0; i < allBytes.Length; ++i)
{
checksum += (uint)allBytes[i];
}
uint checksumComplement = checksum ^ uint.MaxValue;
_writer.Seek(CpuAddressConverter.RAMToPhysical(SfcRomHeader.Checksum, Driver.Header.MapMode), SeekOrigin.Begin);
using (BinaryWriter binWriter = new BinaryWriter(_writer))
{
binWriter.Write((ushort)checksumComplement);
binWriter.Write((ushort)checksum);
}
}
public void Generate()
{
foreach (var instruction in Instructions)
{
var opcodes = instruction.Opcode.GetAttributes <OpcodeAttribute>();
var opcode = opcodes.Where(x => x.AddressingMode == instruction.AddressingMode).First();
switch (instruction.AddressingMode)
{
// Instruction size of 1
case CpuAddressingMode.Implied:
_stream.WriteByte(opcode.Opcode);
break;
case CpuAddressingMode.Immediate:
case CpuAddressingMode.Direct:
case CpuAddressingMode.Absolute:
case CpuAddressingMode.Relative:
{
_stream.WriteByte(opcode.Opcode);
if (instruction.Arguments[0] is NumberInstructionArgument)
{
var numberArgument = instruction.Arguments[0] as NumberInstructionArgument;
if (numberArgument.Size == ArgumentSize.Word ||
numberArgument.Size == ArgumentSize.LongWord)
{
writeWord(numberArgument.Number);
}
else
{
_stream.WriteByte((byte)numberArgument.Number);
}
}
else if (instruction.Arguments[0] is LabelInstructionArgument)
{
var labelArgument = instruction.Arguments[0] as LabelInstructionArgument;
long labelPhysicalAddress = Scope.AddressFor(labelArgument.Label);
if (instruction.AddressingMode == CpuAddressingMode.Relative)
{
byte relativeAddress = Convert.ToByte((labelPhysicalAddress - (_stream.Position + 1)) & 0xFF);
_stream.WriteByte(relativeAddress);
}
else if (instruction.AddressingMode == CpuAddressingMode.Absolute)
{
int ramAddress = CpuAddressConverter.PhysicalToRAM((int)labelPhysicalAddress, Header.MapMode, Header.RomSpeed);
writeWord(ramAddress & 0xFFFF);
}
}
break;
}
}
}
}
private void writeCatridgeHeader()
{
MapMode map = Driver.Header.MapMode;
_writer.Seek(CpuAddressConverter.RAMToPhysical(SfcRomHeader.CatridgeHeader, map), SeekOrigin.Begin);
// Write cartridge title
byte[] cartridgeTitle = new byte[21];
for (int i = 0; i < cartridgeTitle.Length; ++i)
{
cartridgeTitle[i] = (byte)' ';
}
Array.Copy(Encoding.ASCII.GetBytes(Driver.Header.CartridgeName), cartridgeTitle, Encoding.ASCII.GetByteCount(Driver.Header.CartridgeName));
_writer.Write(cartridgeTitle, 0, cartridgeTitle.Length);
// Write ROM Makeup / ROM Speed and map mode
int romMakeup = 0;
romMakeup = (byte)Driver.Header.MapMode
| ((byte)Driver.Header.RomSpeed << 4)
| 1 << 5
;
_writer.WriteByte((byte)romMakeup);
// Write Chipset
byte chipset = 0;
if (Driver.Header.SramSize > 0)
{
chipset = 0x2;
}
_writer.WriteByte(chipset);
// Write ROM size
byte romSize = (byte)Math.Log(32, 2);
_writer.WriteByte(romSize);
// Write RAM size
_writer.WriteByte((byte)Math.Log(Driver.Header.SramSize, 2));
// Write Country
_writer.WriteByte((byte)Driver.Header.Country);
// Write Developer ID
_writer.WriteByte((byte)Driver.Header.Developer);
// Write ROM version
_writer.WriteByte((byte)Driver.Header.Version);
// Write initial checksum complement
_writer.WriteByte(0xFF);
_writer.WriteByte(0xFF);
// Write initial checksum
_writer.WriteByte(0);
_writer.WriteByte(0);
}
private void writeVectors()
{
MapMode map = Driver.Header.MapMode;
_writer.Seek(CpuAddressConverter.RAMToPhysical(SfcRomHeader.NativeVectors, map), SeekOrigin.Begin);
using (BinaryWriter binWriter = new BinaryWriter(_writer))
{
Vectors vectors = Driver.Vectors;
RomSpeed speed = Driver.Header.RomSpeed;
// ==========================
// = Native (65816 vectors) =
// ==========================
// Use BRK version for COP vector
int brk = (int)GlobalScope.AddressFor(vectors.BRK);
brk = CpuAddressConverter.PhysicalToRAM(brk, map, speed);
binWriter.Write((ushort)brk);
// BRK vector
binWriter.Write((ushort)brk);
// Use BRK for ABORT vector
binWriter.Write((ushort)brk);
// NMI vector
int nmi = (int)GlobalScope.AddressFor(vectors.NMI);
nmi = CpuAddressConverter.PhysicalToRAM(nmi, map, speed);
binWriter.Write((ushort)nmi);
// RESET vector
int reset = (int)GlobalScope.AddressFor(vectors.Reset);
reset = CpuAddressConverter.PhysicalToRAM(reset, map, speed);
binWriter.Write((ushort)reset);
// IRQ vector
int irq = (int)GlobalScope.AddressFor(vectors.IRQ);
irq = CpuAddressConverter.PhysicalToRAM(irq, map, speed);
binWriter.Write((ushort)irq);
// ============================
// = Emulation (6502 vectors) =
// ============================
// COP vector
binWriter.Seek(CpuAddressConverter.RAMToPhysical(SfcRomHeader.EmulationCopVector, map), SeekOrigin.Begin);
binWriter.Write((ushort)brk);
// Rest of 6502 vectors
binWriter.Seek(CpuAddressConverter.RAMToPhysical(SfcRomHeader.EmulationVectors, map), SeekOrigin.Begin);
// ABORT
binWriter.Write((ushort)brk);
// NMI
binWriter.Write((ushort)nmi);
// RESET
binWriter.Write((ushort)reset);
// IRQ
binWriter.Write((ushort)irq);
}
}
