public int GetInstructionSize(EnumInstructions inst)
{
if (Sizes.ContainsKey(inst))
{
return(Sizes[inst]);
}
throw new Exception("Tried to get an unsupported instruction size from sizes dictionary.");
}
public void AddInstructionToken(List <Token> tokens, string str, EnumInstructions instructionEnum, EnumInstructionSizes instructionSize = EnumInstructionSizes.Long)
{
Token tkn = new Token(str);
tkn.AddProperty(EnumTokenProperties.TokenType, (Int64)EnumTokenTypes.Instruction);
tkn.AddProperty(EnumTokenProperties.RealInstruction, (Int64)instructionEnum);
tkn.AddProperty(EnumTokenProperties.InstructionSize, (Int64)instructionSize);
tokens.Add(tkn);
}
public bool GetInstruction(out EnumInstructions val)
{
val = EnumInstructions.add;
if (Properties.ContainsKey(EnumTokenProperties.RealInstruction))
{
val = (EnumInstructions)Properties[EnumTokenProperties.RealInstruction];
return(true);
}
throw new TokenAccessException(this, "Failed on accessing Instruction property.");
return(false);
}
public void Tick()
{
//Fetch
buffer[0] = MainMemory.ReadByte(PC);
icode = (byte)(buffer[0] >> 4);
ifun = (byte)(buffer[0] & 0x0F);
instruction = EnumHelper.GetInstructions(icode, ifun);
switch (instruction)
{
case EnumInstructions.halt:
case EnumInstructions.nop:
case EnumInstructions.ret:
valP = 1;
break;
case EnumInstructions.irmov:
case EnumInstructions.rmmov:
case EnumInstructions.mrmov:
//Load rA,rB, and const val into valC
valP = 6;
buffer[0] = MainMemory.ReadByte(PC + 1);
rA = (byte)(buffer[0] >> 4);
rB = (byte)(buffer[0] & 0x0F);
valC = MainMemory.ReadLong(PC + 2);
break;
case EnumInstructions.add:
case EnumInstructions.sub:
case EnumInstructions.imul:
case EnumInstructions.and:
case EnumInstructions.xor:
case EnumInstructions.rrmov:
case EnumInstructions.push:
case EnumInstructions.pop:
//Load rA,rB
valP = 2;
buffer[0] = MainMemory.ReadByte(PC + 1);
rA = (byte)(buffer[0] >> 4);
rB = (byte)(buffer[0] & 0x0F);
break;
case EnumInstructions.jmp:
case EnumInstructions.jle:
case EnumInstructions.jl:
case EnumInstructions.je:
case EnumInstructions.jne:
case EnumInstructions.jge:
case EnumInstructions.jg:
case EnumInstructions.interrupt:
valP = 5;
valC = MainMemory.ReadLong(PC + 1);
break;
}
//Decode
valA.unsigned = (rA <= 14) ? (UInt32)registers[rA] : 0;
valB.unsigned = (rB <= 14) ? (UInt32)registers[rB] : 0;
//Execute
switch (instruction)
{
case EnumInstructions.add:
valE.unsigned = valB.unsigned + valA.unsigned;
flags[(int)EnumConditionCodes.CF] = (valB.unsigned > UInt32.MaxValue - valA.unsigned) ? true : false;
flags[(int)EnumConditionCodes.OF] = false;
if (valA.signed > 0 && valB.signed > 0 && valE.signed < 0)
{
flags[(int)EnumConditionCodes.OF] = true;
break;
}
if (valA.signed < 0 && valB.signed < 0 && valE.signed > 0)
{
flags[(int)EnumConditionCodes.OF] = true;
break;
}
flags[(int)EnumConditionCodes.ZF] = (valE.unsigned == 0);
flags[(int)EnumConditionCodes.SF] = (valE.signed < 0);
break;
case EnumInstructions.sub:
valE.unsigned = valA.unsigned - valB.unsigned;
flags[(int)EnumConditionCodes.CF] = (valA.unsigned < valB.unsigned) ? true : false;
flags[(int)EnumConditionCodes.OF] = false;
if (valB.signed < 0 && valA.signed > 0 && valE.signed < 0)
{
flags[(int)EnumConditionCodes.OF] = true;
break;
}
if (valB.signed > 0 && valA.signed < 0 && valE.signed > 0)
{
flags[(int)EnumConditionCodes.OF] = true;
break;
}
flags[(int)EnumConditionCodes.ZF] = (valE.unsigned == 0);
flags[(int)EnumConditionCodes.SF] = (valE.signed < 0);
break;
case EnumInstructions.and:
valE.unsigned = valB.unsigned & valA.unsigned;
break;
case EnumInstructions.xor:
break;
case EnumInstructions.imul:
valE.unsigned = valB.unsigned * valA.unsigned;
break;
case EnumInstructions.irmov:
valE.unsigned = valC;
break;
case EnumInstructions.rrmov:
valE = valA;
break;
case EnumInstructions.rmmov:
valE.unsigned = valB.unsigned + valC; //valE holds the address
break;
case EnumInstructions.mrmov:
valE.unsigned = valA.unsigned + valC; //rA and rB reversed from example in book pg.389
break;
case EnumInstructions.interrupt:
if (InterruptHandler.InterruptMapping.ContainsKey(valC))
{
InterruptHandler.InterruptMapping[valC].Invoke(this);
}
break;
default:
break;
}
//Memory
if (instruction == EnumInstructions.rmmov)
{
valM = MainMemory.ReadLong(valE.unsigned);
}
else if (instruction == EnumInstructions.mrmov)
{
MainMemory.WriteByte(valE.unsigned, (byte)valA.unsigned);
}
//Write-Back
switch (instruction)
{
case EnumInstructions.add:
case EnumInstructions.sub:
case EnumInstructions.and:
case EnumInstructions.xor:
case EnumInstructions.imul:
case EnumInstructions.irmov:
case EnumInstructions.rrmov:
registers[rB] = valE.unsigned;
break;
case EnumInstructions.mrmov:
registers[rB] = valM; //rA and rB reversed from example in book pg.389
break;
}
//PC Update
switch (instruction)
{
case EnumInstructions.jmp:
PC = valC;
break;
case EnumInstructions.jle:
// (SF != OF) || ZF
PC = ((flags[(int)EnumConditionCodes.SF] != flags[(int)EnumConditionCodes.OF]) || flags[(int)EnumConditionCodes.ZF]) ? valC : PC + valP;
break;
case EnumInstructions.jl:
// (SF != OF)
PC = (flags[(int)EnumConditionCodes.SF] != flags[(int)EnumConditionCodes.OF]) ? valC : PC + valP;
break;
case EnumInstructions.je:
// ZF
PC = (flags[(int)EnumConditionCodes.ZF]) ? valC : PC + valP;
break;
case EnumInstructions.jne:
// !ZF
PC = (!flags[(int)EnumConditionCodes.ZF]) ? valC : PC + valP;
break;
case EnumInstructions.jge:
// !ZF && (SF = OF)
PC = ((flags[(int)EnumConditionCodes.SF] == flags[(int)EnumConditionCodes.OF])) ? valC : PC + valP;
break;
case EnumInstructions.jg:
// !ZF && !SF
PC = (!flags[(int)EnumConditionCodes.ZF] && !flags[(int)EnumConditionCodes.SF]) ? valC : PC + valP;
break;
default:
PC += valP;
valP = 0;
break;
}
}
