public void SelectAlternateExecutionTimings()
{
ExecutionTimings = ParametersVariant.AlternateExecutionTimings;
}
private static void CheckTimings(string instrIds, InstructionExecutionVariant instructionExecutionVariant)
{
int tstates = 0;
for (int mcycle = 1; mcycle <= instructionExecutionVariant.MachineCyclesCount; mcycle++)
{
tstates += instructionExecutionVariant.MachineCycles[mcycle - 1].TStates;
// Check machine cycle types
// 1. OCF or IN is mandatory for cycle 1
if (mcycle == 1 && instructionExecutionVariant.MachineCycles[mcycle - 1].Type != MachineCycleType.OCF)
{
throw new Exception("Instruction does not start with OCF " + instrIds);
}
// 2. OCF is forbidden after cycle 2 unless in case of four bytes opcodes
if (mcycle > 2 && instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.OCF && (mcycle != 4 || instructionExecutionVariant.MachineCycles[mcycle - 2].Type != MachineCycleType.OD))
{
throw new Exception("Too many OCF in instruction " + instrIds);
}
// 3. ODL is always followed by ODH
if (instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.ODL && instructionExecutionVariant.MachineCycles[mcycle].Type != MachineCycleType.ODH)
{
throw new Exception("ODL is always followed by ODH " + instrIds);
}
// 4. MWL is always followed by MWH
if (instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.MWL && instructionExecutionVariant.MachineCycles[mcycle].Type != MachineCycleType.MWH)
{
throw new Exception("MWL is always followed by MWH " + instrIds);
}
// 5. MRL is always followed by MRH
if (instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.MRL && instructionExecutionVariant.MachineCycles[mcycle].Type != MachineCycleType.MRH)
{
throw new Exception("MRL is always followed by MRH " + instrIds);
}
// 6. SWH is always followed by SWL
if (instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.SWH && instructionExecutionVariant.MachineCycles[mcycle].Type != MachineCycleType.SWL)
{
throw new Exception("SWH is always followed by SWL " + instrIds);
}
// 7. SRL is always followed by SRH
if (instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.SRL && instructionExecutionVariant.MachineCycles[mcycle].Type != MachineCycleType.SRH)
{
throw new Exception("SRL is always followed by SRH " + instrIds);
}
// 8. Check minimum duration
if ((instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.OCF ||
instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.PR ||
instructionExecutionVariant.MachineCycles[mcycle - 1].Type == MachineCycleType.PW) &&
instructionExecutionVariant.MachineCycles[mcycle - 1].TStates < 4)
{
throw new Exception("OCF,PR,PW must last at least 4 Tstates " + instrIds);
}
else if (instructionExecutionVariant.MachineCycles[mcycle - 1].TStates < 3)
{
throw new Exception("Machine cycles must last at least 4 Tstates " + instrIds);
}
else if (instructionExecutionVariant.MachineCycles[mcycle - 1].TStates > 6)
{
throw new Exception("Machine cycles can last at most 6 Tstates " + instrIds);
}
}
if (tstates != instructionExecutionVariant.TStatesCount)
{
throw new Exception("Problem of timings with instruction " + instrIds);
}
}
public Instruction(int instructionTypeIndex, int instructionTypeParamVariant)
{
Type = Z80InstructionTypes.Table[instructionTypeIndex];
ParametersVariant = Type.ParametersVariants[instructionTypeParamVariant];
ExecutionTimings = ParametersVariant.ExecutionTimings;
}
