public void Visit(LessThanOperator lessThan)
{
lessThan.Left.Accept(this);
var leftOperand = tacs.Last().Result;
lessThan.Right.Accept(this);
var rightOperand = tacs.Last().Result;
var result = MakeNewTemp();
var label1 = MakeNewLabel();
var label2 = MakeNewLabel();
tacs.Add(Tac.IfLessThan(leftOperand, rightOperand, label1));
tacs.Add(Tac.Assign("0", result));
tacs.Add(Tac.Goto(label2));
tacs.Add(Tac.Label(label1, result));
tacs.Add(Tac.Assign("1", result));
tacs.Add(Tac.Label(label2, result));
}
public void Visit(EqualsOperator equals)
{
equals.Left.Accept(this);
var leftOperand = tacs.Last().Result;
equals.Right.Accept(this);
var rightOperand = tacs.Last().Result;
var result = MakeNewTemp();
var label1 = MakeNewLabel();
var label2 = MakeNewLabel();
tacs.Add(Tac.IfEqual(leftOperand, rightOperand, label1));
tacs.Add(Tac.Assign("0", result));
tacs.Add(Tac.Goto(label2));
tacs.Add(Tac.Label(label1, result));
tacs.Add(Tac.Assign("1", result));
tacs.Add(Tac.Label(label2, result));
}
public void Visit(IfThenElse ifthenelse)
{
var elseLabel = MakeNewLabel();
var endLabel = MakeNewLabel();
var resultVariable = MakeNewTemp();
ifthenelse.IfExpr.Accept(this);
var ifoperand = tacs.Last().Result;
tacs.Add(Tac.IfFalse(ifoperand, elseLabel));
ifthenelse.ThenExpr.Accept(this);
tacs.Add(Tac.Assign(tacs.Last().Result, resultVariable));
tacs.Add(Tac.Goto(endLabel));
tacs.Add(Tac.Label(elseLabel, resultVariable));
ifthenelse.ElseExpr.Accept(this);
tacs.Add(Tac.Assign(tacs.Last().Result, resultVariable));
tacs.Add(Tac.Label(endLabel, resultVariable));
}
public void Visit(AndOperator and)
{
var falseLabel = MakeNewLabel();
var endLabel = MakeNewLabel();
and.Left.Accept(this);
var leftOperand = tacs.Last().Result;
tacs.Add(Tac.IfFalse(leftOperand, falseLabel));
and.Right.Accept(this);
var rightOperand = tacs.Last().Result;
tacs.Add(Tac.IfFalse(rightOperand, falseLabel));
var resultVariable = MakeNewTemp();
tacs.Add(Tac.Assign("1", resultVariable));
tacs.Add(Tac.Goto(endLabel));
tacs.Add(Tac.Label(falseLabel, resultVariable));
tacs.Add(Tac.Assign("0", resultVariable));
tacs.Add(Tac.Label(endLabel, resultVariable));
}
public void Visit(OrOperator or)
{
var trueLabel = MakeNewLabel();
var endLabel = MakeNewLabel();
or.Left.Accept(this);
var leftOperand = tacs.Last().Result;
tacs.Add(Tac.IfTrue(leftOperand, trueLabel));
or.Right.Accept(this);
var rightOperand = tacs.Last().Result;
tacs.Add(Tac.IfTrue(rightOperand, trueLabel));
var resultVariable = MakeNewTemp();
tacs.Add(Tac.Assign("0", resultVariable));
tacs.Add(Tac.Goto(endLabel));
tacs.Add(Tac.Label(trueLabel, resultVariable));
tacs.Add(Tac.Assign("1", resultVariable));
tacs.Add(Tac.Label(endLabel, resultVariable));
}