/// <summary>
/// Constructs a Code Node that has asm commands representing a free register allocation (if all are allocated already).
/// Some variables could be deallocated randomly when calling this function.
/// </summary>
/// <param name="ctx">Current context.</param>
/// <param name="parent">Parent Code Node</param>
/// <returns>Constructed Code Node with asm commands representing a free register allocation.</returns>
protected CodeNode GetFreeRegisterNode(Context?ctx, CodeNode?parent)
{
Generator g = Program.currentCompiler.generator;
CodeNode frNode = new CodeNode("Get free register", parent);
for (byte ri = 0; ri < g.regOccup.Length; ri++)
{
if (!g.regOccup[ri])
{
g.OccupateReg(ri);
return(frNode.SetByteToReturn(ri));
}
}
// If all are occupated, load out one of them (the first suitable one).
// ATTENTION: Is it ok, or am I stupid?
byte regToFree = 0;
while (regToFree < 27) // God bless this while to not loop forever! NOTE: It won't
{
if (g.regAllocRTV.ContainsKey(regToFree))
{
break;
}
regToFree++;
}
if (g.regAllocRTV.ContainsKey(regToFree))
{
string varName = g.regAllocRTV[regToFree];
g.regAllocRTV.Remove(regToFree);
g.regAllocVTR.Remove(varName);
frNode.Children.AddLast(GetStoreVariableNode(frNode, varName, regToFree, ctx));
return(frNode.SetByteToReturn(regToFree));
}
else
{
throw new CompilationErrorException("Out of registers!!!");
}
}