private static void printOperands(Instruction i)
{
int a, b, c, ax, bx, sbx;
switch (i.OpMode())
{
case OpCodes.IABC:
var abc = i.ABC();
Console.Write($"{abc.Item1:D}", abc.Item1);
if (i.BMode() != OpCodes.OpArgN)
{
if (abc.Item2 > 0xFF)
{
Console.Write($" {-1 - (abc.Item2 & 0xFF):D}");
}
else
{
Console.Write($" {abc.Item2:D}");
}
}
if (i.CMode() != OpCodes.OpArgN)
{
if (abc.Item3 > 0xFF)
{
Console.Write($"{-1 - (abc.Item3 & 0xFF):D}");
}
else
{
Console.Write($" {abc.Item3:D}");
}
}
break;
case OpCodes.IABx:
var aBx = i.ABx();
Console.Write($" {aBx.Item1:D}");
if (i.BMode() == OpCodes.OpArgK)
{
Console.Write($"{-1 - aBx.Item2:D}");
}
else if (i.BMode() == OpCodes.OpArgU)
{
Console.Write($" {aBx.Item2:D}");
}
break;
case OpCodes.IAsBx:
var asBx = i.AsBx();
Console.Write($"{asBx.Item1:D} {asBx.Item2:D}");
break;
case OpCodes.IAx:
ax = i.Ax();
Console.Write($"{-1 - ax:D}");
break;
}
}
internal static void TForLoop(Instruction i, ILuaVM vm)
{
var(a, sBx) = i.AsBx();
a += 1;
if (!vm.IsNil(a + 1))
{
vm.Copy(a + 1, a);
vm.AddPC(sBx);
}
}
internal static void ForPrep(Instruction i, ILuaVM vm)
{
var(a, sBx) = i.AsBx();
a += 1;
// R(A)-=R(A+2)
vm.PushValue(a);
vm.PushValue(a + 2);
vm.Arith(ArithOp.Sub);
vm.Replace(a);
// pc += sBx
vm.AddPC(sBx);
}
internal static void ForLoop(Instruction i, ILuaVM vm)
{
var(a, sBx) = i.AsBx();
a += 1;
// R(A)+=R(A+2)
vm.PushValue(a + 2);
vm.PushValue(a);
vm.Arith(ArithOp.Add);
vm.Replace(a);
// R(A)<?=R(A+1)
bool isPositiveStep = vm.ToNumber(a + 2) >= 0;
if ((isPositiveStep && vm.Compare(a, a + 1, CompareOp.Le)) ||
(!isPositiveStep && vm.Compare(a + 1, a, CompareOp.Le)))
{
vm.AddPC(sBx); // pc+=sBx
vm.Copy(a, a + 3); // R(A+3)=R(A)
}
}