/// <summary>
/// Takes several opcode information and returns the best match of InstructionFormKind and InstructionOperandCountKind.
/// </summary>
/// <param name="opcodeNumber">The opcode number.</param>
/// <param name="opcodeType">The opcode type as written in the table of opcodes.</param>
/// <param name="operands">The operands to use.</param>
/// <returns>A tuple of InstructionFormKind and InstructionOperandCountKind.</returns>
/// <exception cref="ArgumentOutOfRangeException"> If <paramref name="opcodeNumber"/> has an invalid value or <paramref name="operands"/> an invalid count of operands.</exception>
/// <exception cref="ArgumentException"> If <paramref name="operands"/> contains an unknown enum value.</exception>
public static Tuple<InstructionFormKind, InstructionOperandCountKind> GetFormAndCount(byte opcodeNumber, OpcodeTypeKind opcodeType, ZOperand[] operands)
{
InstructionFormKind instructionForm;
InstructionOperandCountKind operandCount;
if (opcodeType == OpcodeTypeKind.ZeroOP)
{
if (opcodeNumber > 0xF)
throw new ArgumentOutOfRangeException("opcodeNumber", opcodeNumber, "The opcode number of an OpcodeTypeKind.ZeroOP must be in range of 0x0 - 0xF.");
if (operands.Count() > 0)
throw new ArgumentOutOfRangeException("operands", operands.Count(), "With OpcodeTypeKind.ZeroOP no operands must be given.");
instructionForm = InstructionFormKind.Short;
operandCount = InstructionOperandCountKind.ZeroOP;
}
else if (opcodeType == OpcodeTypeKind.OneOP)
{
if (opcodeNumber > 0xF)
throw new ArgumentOutOfRangeException("opcodeNumber", opcodeNumber, "The opcode number of an OpcodeTypeKind.OneOP must be in range of 0x0 - 0xF.");
if (operands.Count() != 1)
throw new ArgumentOutOfRangeException("operands", operands.Count(), "With OpcodeTypeKind.OneOP excactly operands must be given.");
instructionForm = InstructionFormKind.Short;
operandCount = InstructionOperandCountKind.OneOP;
}
else if (opcodeType == OpcodeTypeKind.TwoOP)
{
if (opcodeNumber > 0x1F)
throw new ArgumentOutOfRangeException("opcodeNumber", opcodeNumber, "The opcode number of an OpcodeTypeKind.TwoOP must be in range of 0x00 - 0x1F.");
if (operands.Count() != 2)
throw new ArgumentOutOfRangeException("operands", operands.Count(), "With OpcodeTypeKind.TwoOP exactly two operands must be given.");
// Could be in long form for two small constants or variables
// But let's keep this logic dumb
// We could save 1 byte per OpcodeTypeKind.TwoOP at best
instructionForm = InstructionFormKind.Variable;
operandCount = InstructionOperandCountKind.TwoOP;
}
else if (opcodeType == OpcodeTypeKind.Var)
{
if (opcodeNumber > 0x1F)
throw new ArgumentOutOfRangeException("opcodeNumber", opcodeNumber, "The opcode number of an OpcodeTypeKind.Var must be in range of 0x00-0x1F.");
if (operands.Count() > 4)
{
if (operands.Count() <= 8)
throw new ArgumentOutOfRangeException("operands", operands.Count(), "With OpcodeTypeKind.Var only 0 to 4 operands can be given. Up to 8 operands are not supported yet (only call_vs2 and call_vn2 make use of this).");
else
throw new ArgumentOutOfRangeException("operands", operands.Count(), "With OpcodeTypeKind.Var only 0 to 4 operands can be given.");
}
instructionForm = InstructionFormKind.Variable;
operandCount = InstructionOperandCountKind.Var;
}
else if (opcodeType == OpcodeTypeKind.Ext)
{
if (operands.Count() > 4)
throw new ArgumentOutOfRangeException("operands", operands.Count(), "With OpcodeTypeKind.Ext only 0 to 4 operands can be given.");
instructionForm = InstructionFormKind.Extended;
operandCount = InstructionOperandCountKind.Var;
}
else
throw new ArgumentException(String.Format("Unknown OpcodeTypeKind '{0}'", opcodeType.ToString()), "opcodeType");
return new Tuple<InstructionFormKind, InstructionOperandCountKind>(instructionForm, operandCount);
}
