// Recognize and translate a relational equals
private void RelEquals()
{
Cradle.Match('=');
Expression();
Cradle.EmitLn("CMP (SP)+,D0");
Cradle.EmitLn("SEQ D0");
}
// Recognize and translate a relational not equals
private void NotEquals()
{
Cradle.Match('#');
Expression();
Cradle.EmitLn("CMP (SP)+,D0");
Cradle.EmitLn("SNE D0");
}
// Parse and translate an assignment statement
private void Assignment()
{
char Name = Cradle.GetName();
Cradle.Match('=');
Table[Name - 'A'] = Expression();
}
// Recognize and translate a relational less than
private void Less()
{
Cradle.Match('<');
Expression();
Cradle.EmitLn("CMP (SP)+,D0");
Cradle.EmitLn("SGE D0");
}
// Recognize and translate a relational greater than
private void Greater()
{
Cradle.Match('>');
Expression();
Cradle.EmitLn("CMP (SP)+,D0");
Cradle.EmitLn("SLE D0");
}
// Parse and translate a for statement
private void DoFor()
{
Cradle.Match('f');
string L1 = Label.NewLabel();
string L2 = Label.NewLabel();
char Name = Cradle.GetName();
Cradle.Match('=');
Expression();
Cradle.EmitLn("SUBQ #1,D0");
Cradle.EmitLn("LEA " + Name + "(PC),A0");
Cradle.EmitLn("MOVE D0,(A0)");
Expression();
Cradle.EmitLn("MOVE D0,-(SP)");
Label.PostLabel(L1);
Cradle.EmitLn("LEA " + Name + "(PC),A0");
Cradle.EmitLn("ADDQ #1,D0");
Cradle.EmitLn("MOVE D0,(A0)");
Cradle.EmitLn("CMP (SP),D0)");
Cradle.EmitLn("BGT " + L2);
Block(L2);
Cradle.Match('e');
Cradle.EmitLn("BRA " + L1);
Label.PostLabel(L2);
Cradle.EmitLn("ADDQ #2,SP");
}
// Lexical scanner
private void Scan()
{
int k;
while (Cradle.Look == Cradle.CR)
{
Cradle.Fin();
}
if (Cradle.IsAlpha(Cradle.Look))
{
GetName();
}
else if (Cradle.IsDigit(Cradle.Look))
{
GetNum();
}
else if (IsOp(Cradle.Look))
{
GetOp();
}
else
{
Value = Cradle.Look.ToString();
Token = SymType.Operator;
Cradle.GetChar();
}
Cradle.SkipWhite();
}
// 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");
}
// Recognize and translate a break
private void DoBreak(string L)
{
Cradle.Match('b');
if (L.Length > 0)
Cradle.EmitLn("BRA " + L);
else
Cradle.Abort("No loop to break");
}
// Parse and translate an assignment statement
private void Assignment()
{
char name = Cradle.GetName();
Cradle.Match('=');
BoolExpression();
Cradle.EmitLn("LEA " + name + "(PC),A0");
Cradle.EmitLn("MOVE D0,(A0)");
}
// Parse and translate a program
private void DoProgram()
{
Block("");
if (Cradle.Look != 'e')
{
Cradle.Expected("End");
}
Cradle.EmitLn("END");
}
// Skip over a comma
private void SkipComma()
{
Cradle.SkipWhite();
if (Cradle.Look == ',')
{
Cradle.GetChar();
Cradle.SkipWhite();
}
}
// Parse and translate a loop statement
private void DoLoop()
{
Cradle.Match('p');
string L1 = Label.NewLabel();
string L2 = Label.NewLabel();
Label.PostLabel(L1);
Block(L2);
Cradle.Match('e');
Cradle.EmitLn("BRA " + L1);
Label.PostLabel(L2);
}
// Parse and translate a Boolean factor with not
private void NotFactor()
{
if (Cradle.Look == '!')
{
Cradle.Match('!');
BoolFactor();
Cradle.EmitLn("EOR #-1,D0");
}
else
BoolFactor();
}
// Parse and translate a Boolean factor
private void BoolFactor()
{
if (Cradle.IsBoolean(Cradle.Look))
{
if (Cradle.GetBoolean())
Cradle.EmitLn("MOVE #-1,D0");
else
Cradle.EmitLn("CLR D0");
}
Relation();
}
// Parse and recognize a Boolean term
private void BoolTerm()
{
NotFactor();
while (Cradle.Look == '&')
{
Cradle.EmitLn("MOVE D0,-(SP)");
Cradle.Match('&');
NotFactor();
Cradle.EmitLn("AND (SP)+,D0");
}
}
// Parse and translate a repeat block
private void DoRepeat()
{
Cradle.Match('r');
string L1 = Label.NewLabel();
string L2 = Label.NewLabel();
Label.PostLabel(L1);
Block(L2);
Cradle.Match('u');
BoolExpression();
Cradle.EmitLn("BEQ " + L1);
Label.PostLabel(L2);
}
// Parse and translate an identity
private void Ident()
{
char 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 a Boolean expression
private void BoolExpression()
{
BoolTerm();
while (IsOrop(Cradle.Look))
{
Cradle.EmitLn("MOVE D0,-(SP)");
switch (Cradle.Look)
{
case '|': BoolOr(); break;
case '~': BoolXor(); break;
}
}
}
// Parse and translate a math term
private void Term()
{
SignedFactor();
while ("*/".IndexOf(Cradle.Look) > -1)
{
Cradle.EmitLn("MOVE D0,-(SP)");
switch (Cradle.Look)
{
case '*': Multiply(); break;
case '/': Divide(); break;
}
}
}
// Parse and translate a math factor
private void Factor()
{
if (Cradle.Look == '(')
{
Cradle.Match('(');
Expression();
Cradle.Match(')');
}
else if (Cradle.IsAlpha(Cradle.Look))
Ident();
else
Cradle.EmitLn("MOVE #" + Cradle.GetNum() + ",D0");
}
// Parse and translate a while statement
private void DoWhile()
{
Cradle.Match('w');
string L1 = Label.NewLabel();
string L2 = Label.NewLabel();
Label.PostLabel(L1);
BoolExpression();
Cradle.EmitLn("BEQ " + L2);
Block(L2);
Cradle.Match('e');
Cradle.EmitLn("BRA " + L1);
Label.PostLabel("L2");
}
// Get an identifier
private void GetName()
{
Value = "";
if (!Cradle.IsAlpha(Cradle.Look))
{
Cradle.Expected("Name");
}
while (Cradle.IsAlNum(Cradle.Look))
{
Value += char.ToUpper(Cradle.Look);
Cradle.GetChar();
}
Token = KWCode[Lookup(Value) + 1];
}
// Get an operator
private void GetOp()
{
Value = "";
if (!IsOp(Cradle.Look))
{
Cradle.Expected("Operator");
}
while (IsOp(Cradle.Look))
{
Value += Cradle.Look;
Cradle.GetChar();
}
Token = SymType.Operator;
}
// Get a number
private void GetNum()
{
Value = "";
if (!Cradle.IsDigit(Cradle.Look))
{
Cradle.Expected("Integer");
}
while (Cradle.IsDigit(Cradle.Look))
{
Value += Cradle.Look;
Cradle.GetChar();
}
Token = SymType.Number;
}
// Parse and translate a relation
private void Relation()
{
Expression();
if (IsRelop(Cradle.Look))
{
Cradle.EmitLn("MOVE D0,-(SP)");
switch (Cradle.Look)
{
case '=': RelEquals(); break;
case '#': NotEquals(); break;
case '<': Less(); break;
case '>': Greater(); break;
}
Cradle.EmitLn("TST D0");
}
}
// Parse and translate the first math factor
private void SignedFactor()
{
if (Cradle.Look == '+') Cradle.GetChar();
if (Cradle.Look == '-')
{
Cradle.GetChar();
if (Cradle.IsDigit(Cradle.Look))
Cradle.EmitLn("MOVE #-" + Cradle.GetNum() + ",D0");
else
{
Factor();
Cradle.EmitLn("NEG D0");
}
}
else
Factor();
}
// 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;
}
}
}
// Parse and translate a do statement
private void DoDo()
{
Cradle.Match('d');
string L1 = Label.NewLabel();
string L2 = Label.NewLabel();
Expression();
Cradle.EmitLn("SUBQ #1,D0");
Label.PostLabel(L1);
Cradle.EmitLn("MOVE D0,-(SP)");
Block(L2);
Cradle.Match('e');
Cradle.EmitLn("MOVE (SP)+,D0");
Cradle.EmitLn("DBRA D0," + L1);
Cradle.EmitLn("SUBQ #2,SP");
Label.PostLabel(L2);
Cradle.EmitLn("ADDQ #2,SP");
}