// Recognize and translate a divide
private void Divide()
{
Cradle.Match('/');
Factor();
Cradle.EmitLn("MOVE(SP)+,D1");
Cradle.EmitLn("DIVS D1,D0");
}
// Recognize and translate a subtract
private void Subtract()
{
Cradle.Match('-');
Term();
Cradle.EmitLn("SUB (SP)+,D0");
Cradle.EmitLn("NEG D0");
}
public Compiler()
{
Assignment();
if (Cradle.Look != Cradle.CR)
{
Cradle.Expected("Newline");
}
}
// Parse and translate an assignment statement
private void Assignment()
{
string name = Cradle.GetName();
Cradle.Match('=');
Expression();
Cradle.EmitLn("LEA " + name + "(PC),A0");
Cradle.EmitLn("MOVE D0,(A0)");
}
// Parse and translate a math factor
private void Factor()
{
if (Cradle.Look == '(')
{
Cradle.Match('(');
Expression();
Cradle.Match(')');
}
else
{
Cradle.EmitLn("MOVE #" + Cradle.GetNum() + ",D0");
}
}
// Parse and translate a math term
private void Term()
{
Factor();
while ("*/".IndexOf(Cradle.Look) > -1)
{
Cradle.EmitLn("MOVE D0,-(SP)");
switch (Cradle.Look)
{
case '*': Multiply(); break;
case '/': Divide(); break;
}
}
}
// Parse and translate an identity
private void Ident()
{
string name = Cradle.GetName();
if (Cradle.Look == '(')
{
Cradle.Match('(');
Expression();
Cradle.Match(')');
Cradle.EmitLn("BSR " + name);
}
else
{
Cradle.EmitLn("MOVE " + name + "(PC),D0");
}
}
// Parse and translate an expression
private void Expression()
{
if (Cradle.IsAddop(Cradle.Look))
{
Cradle.EmitLn("CLR D0");
}
else
{
Term();
}
while (Cradle.IsAddop(Cradle.Look))
{
Cradle.EmitLn("MOVE D0,-(SP)");
switch (Cradle.Look)
{
case '+': Add(); break;
case '-': Subtract(); break;
}
}
}
// Recognize and translate an add
private void Add()
{
Cradle.Match('+');
Term();
Cradle.EmitLn("ADD (SP)+,D0");
}
// Recognize and translate a multiply
private void Multiply()
{
Cradle.Match('*');
Factor();
Cradle.EmitLn("MULS (SP)+,D0");
}