private static Update UpdateState(IList <Instruction> instructions, State state, PushedArgs pushedArgs)
{
if (state.index < 0 || state.index >= instructions.Count)
{
return(Update.Fail);
}
var instr = instructions[state.index];
if (!Instr.IsFallThrough(instr.OpCode))
{
return(Update.Fail);
}
instr.CalculateStackUsage(false, out int pushes, out int pops);
if (pops == -1)
{
return(Update.Fail);
}
var isDup = instr.OpCode.Code == Code.Dup;
if (isDup)
{
pushes = 1;
pops = 0;
}
if (pushes > 1)
{
return(Update.Fail);
}
if (state.skipPushes > 0)
{
state.skipPushes -= pushes;
if (state.skipPushes < 0)
{
return(Update.Fail);
}
state.skipPushes += pops;
}
else
{
if (pushes == 1)
{
if (isDup)
{
state.addPushes++;
}
else
{
for (; state.addPushes > 0; state.addPushes--)
{
pushedArgs.Add(instr);
state.validArgs++;
if (!pushedArgs.CanAddMore)
{
return(Update.Finish);
}
}
state.addPushes = 1;
}
}
state.skipPushes += pops;
}
return(Update.Ok);
}
