static void IfStatement(StackFrame frame)
{
Label falseLabel = new Label(!known);
Label endLabel = new Label(!known);
Label ifelLabel = new Label(!known);
Expect(if_Sym);
Expect(lparen_Sym);
Condition();
Expect(rparen_Sym);
CodeGen.BranchFalse(falseLabel);
Statement(frame);
CodeGen.Branch(endLabel);
falseLabel.Here();
while (la.kind == elseif_Sym)
{
Get();
Expect(lparen_Sym);
Condition();
Expect(rparen_Sym);
ifelLabel = new Label(!known);
CodeGen.BranchFalse(ifelLabel);
Statement(frame);
CodeGen.Branch(endLabel);
ifelLabel.Here();
}
if (la.kind == else_Sym)
{
Get();
Statement(frame);
}
endLabel.Here();
}
static void WhileStatement(StackFrame frame)
{
Label loopExit = new Label(!known);
Label loopStart = new Label(known);
Expect(while_Sym);
Expect(lparen_Sym);
Condition();
Expect(rparen_Sym);
CodeGen.BranchFalse(loopExit);
Statement(frame);
CodeGen.Branch(loopStart);
loopExit.Here();
}
static void WhileStatement(StackFrame frame)
{
Label loopExit = new Label(!known);
Label loopStart = new Label(known);
Expect(while_Sym);
Expect(lparen_Sym);
Condition();
Expect(rparen_Sym);
CodeGen.BranchFalse(loopExit);
Statement(frame);
if (token.val == ";")
{
Warning("Can not have an empty statement.");
}
CodeGen.Branch(loopStart);
loopExit.Here();
}