protected internal override void VisitAST(ForStmtAST node)
{
this.Visit(node.PreRun); // init
var(postLabel, endLabel) = OpenLoop();
var beginLabel = Ins.CreateLabel();
GenCode.Add(Ins.Label(beginLabel));
this.Visit(node.InfLoop.Cond);
// repeat's logic is opposite to for
if (node.NodeType == ASTType.Repeat)
{
GenCode.Add(Ins.Not());
}
GenCode.Add(Ins.Fjp(endLabel));
// body
this.Visit(node.InfLoop.Body);
// post run
GenCode.Add(Ins.Label(postLabel));
this.Visit(node.PostRun);
// jump to cond
GenCode.Add(Ins.Ujp(beginLabel));
GenCode.Add(Ins.Label(endLabel));
CloseLoop();
}
protected internal override void VisitAST(BinaryExprAST node)
{
// for convenience, convert both of the LHS and RHS type explicitly
var ty = (TypeKind) Math.Max((int) node.Lhs.RetType, (int) node.Rhs.RetType);
this.Visit(node.Lhs);
GenCode.Add(Ins.Conv(node.Lhs.RetType,ty));
this.Visit(node.Rhs);
GenCode.Add(Ins.Conv(node.Rhs.RetType, ty));
var code = node.NodeType switch
{
ASTType.Add => Ins.Add(ty),
ASTType.Subtract => Ins.Sub(ty),
ASTType.Multiply => Ins.Mul(ty),
ASTType.Divide => Ins.Div(ty),
ASTType.Modulo => Ins.Mod(),
ASTType.Equal => Ins.Equ(ty),
ASTType.NotEqual => Ins.Neq(ty),
ASTType.LessThan => Ins.Les(ty),
ASTType.LessEqual => Ins.Leq(ty),
ASTType.GreaterThan => Ins.Grt(ty),
ASTType.GreaterEqual => Ins.Geq(ty),
ASTType.And => Ins.And(),
ASTType.Or => Ins.Or(),
_ => throw new NotImplementedException()
};
GenCode.Add(code);
}
public override void Clear()
{
Ins.CleanLabel();
GenCode.Clear();
_symTbl.Clear();
_loops.Clear();
_allocated = 0;
}
protected internal override void VisitAST(AssignStmtAST node)
{
if (!HasId(node.Name))
{
RegisterId(node.Name, node.Value.RetType);
}
var(ty, addr) = GetId(node.Name);
this.Visit(node.Value);
GenCode.Add(Ins.Dpl(ty)); // duplicate the stack top first
GenCode.Add(Ins.Str(ty, 0, addr)); // then move to the specified addr, sp--
}
protected internal override void VisitAST(UnaryExprAST node)
{
this.Visit(node.Hs);
var code = node.NodeType switch
{
ASTType.Not => Ins.Not(),
ASTType.Neg => Ins.Neg(node.RetType),
_ => throw new NotImplementedException()
};
GenCode.Add(code);
}
protected internal override void VisitAST(IfStmtAST node)
{
var elseLabel = Ins.CreateLabel();
var endLabel = Ins.CreateLabel();
Branch ifBranch = node.Branches.First();
this.Visit(ifBranch.Cond);
GenCode.Add(Ins.Fjp(elseLabel));
this.Visit(ifBranch.Body);
GenCode.Add(Ins.Ujp(endLabel));
GenCode.Add(Ins.Label(elseLabel));
this.Visit(node.ElseBranch?.Body);
GenCode.Add(Ins.Label(endLabel));
}
protected internal override void VisitAST(RepeatStmtAST node)
{
var(beginLabel, endLabel) = OpenLoop();
GenCode.Add(Ins.Label(beginLabel));
this.Visit(node.InfLoop.Body);
// repeat's logic is opposite to for
this.Visit(node.InfLoop.Cond);
GenCode.Add(Ins.Not());
GenCode.Add(Ins.Fjp(endLabel));
GenCode.Add(Ins.Ujp(beginLabel));
GenCode.Add(Ins.Label(endLabel));
CloseLoop();
}
protected internal override void VisitAST(WriteStmtAST node)
{
this.Visit(node.Value);
GenCode.Add(Ins.Out(node.Value.RetType));
}
protected internal override void VisitAST(ReadStmtAST node)
{
RegisterId(node.Name, node.VarType);
GenCode.Add(Ins.In(node.VarType));
}
protected internal override void VisitAST(ContinueStmtAST node)
{
GenCode.Add(Ins.Ujp(LoopStart));
}
protected internal override void VisitAST(BreakStmtAST node)
{
GenCode.Add(Ins.Ujp(LoopEnd));
}
protected internal override void VisitAST(IntExprAST node)
{
GenCode.Add(Ins.Ldc(node.RetType, node.Value));
}
protected internal override void VisitAST(BoolExprAST node)
{
GenCode.Add(Ins.Ldc(TypeKind.Bool, node.Value ? "t" : "f"));
}
protected internal override void VisitAST(VariableExprAST node)
{
var (_, addr) = GetId(node.Name);
GenCode.Add(Ins.Lod(node.RetType, 0, addr));
}
protected internal override void VisitAST(FloatExprAST node)
{
GenCode.Add(Ins.Ldc(TypeKind.Float, node.Value));
}