/// <summary>
/// Fetches a word (aka ushort, aka UInt16) from specified address.
/// The byte order is little endian, so the the least significant byte (lowbyte) is assumed to at address,
/// and most significant byte is assumed to be at address + 1.
/// </summary>
/// <param name="mem"></param>
/// <param name="address"></param>
/// <returns></returns>
public static ushort FetchWord(this Memory mem, ushort address)
{
byte byte1 = mem[address];
byte byte2 = mem[(ushort)(address + 1)];
return(ByteHelpers.ToLittleEndianWord(byte1, byte2));
}
public static void Run()
{
Console.WriteLine($"-----------------------------------------------------");
Console.WriteLine($"Run 6502 code that copies data between two addresses.");
Console.WriteLine($"-----------------------------------------------------");
string prgFileName = "../.cache/ConsoleTestPrograms/testprogram.prg";
Console.WriteLine($"Program binary file: {prgFileName}");
if (!File.Exists(prgFileName))
{
Console.WriteLine($"File does not exist.");
return;
}
// Load binary file
byte[] fileData = File.ReadAllBytes(prgFileName);
// First two bytes of binary file is assumed to be start address, little endian notation.
ushort startPos = ByteHelpers.ToLittleEndianWord(fileData[0], fileData[1]);
// The rest of the bytes are considered the code
byte[] code = new byte[fileData.Length - 2];
Array.Copy(fileData, 2, code, 0, fileData.Length - 2);
Console.WriteLine($"Code memory address: {startPos:X4} / {startPos}");
Console.WriteLine($"Code length (bytes): {code.Length:X4} / {code.Length}");
Console.WriteLine("Creating memory...");
Memory mem = new();
ushort testDataAddress = 0x1000;
Console.WriteLine($"Loading test-data into memory address: {testDataAddress:X4}");
mem.WriteByte(ref testDataAddress, 0x01);
mem.WriteByte(ref testDataAddress, 0x02);
mem.WriteByte(ref testDataAddress, 0x03);
testDataAddress = 0x10fe;
mem.WriteByte(ref testDataAddress, 0xa3);
mem.WriteByte(ref testDataAddress, 0xa2);
mem.WriteByte(ref testDataAddress, 0xa1);
//Console.WriteLine("Press Enter to start");
//Console.ReadLine();
// Load code in to memory at start position
Console.WriteLine("Loading code into memory...");
mem.StoreData(startPos, code);
// Initialize CPU, set PC to start position
Console.WriteLine("Initializing CPU...");
CPU cpu = new();
cpu.PC = startPos;
var execOptions = new ExecOptions
{
UnknownInstructionThrowsException = true,
ExecuteUntilInstruction = OpCodeId.BRK
};
// Execute program
Console.WriteLine("Executing code...");
//var consumedCycles = cpu.Execute(mem, 10000, maxNumberOfInstructions: 1 + (4*256));
var consumedCycles = cpu.Execute(mem, execOptions);
Console.WriteLine("Program ended.");
Console.WriteLine($"Consumed cycles: {consumedCycles}");
ushort verifySrcAddress = 0x1000;
ushort verifyDestAddress = 0x2000;
Console.WriteLine($"Comparing data in source {verifySrcAddress:X4} with destination {verifyDestAddress:X4}");
Console.WriteLine($"{verifySrcAddress:X4} = {mem.FetchByte(ref verifySrcAddress):X2}, {verifyDestAddress:X4} = {mem.FetchByte(ref verifyDestAddress):X2} ");
Console.WriteLine($"{verifySrcAddress:X4} = {mem.FetchByte(ref verifySrcAddress):X2}, {verifyDestAddress:X4} = {mem.FetchByte(ref verifyDestAddress):X2} ");
Console.WriteLine($"{verifySrcAddress:X4} = {mem.FetchByte(ref verifySrcAddress):X2}, {verifyDestAddress:X4} = {mem.FetchByte(ref verifyDestAddress):X2} ");
verifySrcAddress = 0x10fe;
verifyDestAddress = 0x20fe;
Console.WriteLine($"Comparing data in source {verifySrcAddress:X4} with destination {verifyDestAddress:X4}");
Console.WriteLine($"{verifySrcAddress:X4} = {mem.FetchByte(ref verifySrcAddress):X2}, {verifyDestAddress:X4} = {mem.FetchByte(ref verifyDestAddress):X2} ");
Console.WriteLine($"{verifySrcAddress:X4} = {mem.FetchByte(ref verifySrcAddress):X2}, {verifyDestAddress:X4} = {mem.FetchByte(ref verifyDestAddress):X2} ");
Console.WriteLine($"{verifySrcAddress:X4} = {mem.FetchByte(ref verifySrcAddress):X2}, {verifyDestAddress:X4} = {mem.FetchByte(ref verifyDestAddress):X2} ");
}