public static string MakeAddressForEntry(Entry entry, string specialName = "")
{
LinkedList <string> names = new LinkedList <string>();
while (entry != null)
{
names.AddFirst(entry.getName());
if (entry.getParent() == null)
{
break;
}
entry = entry.getParent().getParent();
}
if (!string.IsNullOrEmpty(specialName))
{
names.AddFirst(specialName);
}
names.AddLast(IDGenerator.GetNext());
return(string.Join("_", names));
}
public override List <string> ExecuteSemanticAction(Stack <SemanticRecord> semanticRecordTable, Stack <SymbolTable> symbolTable, IToken lastToken, MoonCodeResult moonCode)
{
Token op = null;
LinkedList <ExpressionRecord> expressions = new LinkedList <ExpressionRecord>();
List <string> errors = new List <string>();
// Accumulate the two last expressions on the semantic stack
while (expressions.Count < 2)
{
if (!semanticRecordTable.Any())
{
errors.Add(string.Format("Grammar error: Not enough expressions to validate arithmetic operation at line {0}", lastToken.getLine()));
return(errors);
}
SemanticRecord record = semanticRecordTable.Pop();
BasicTokenRecord tokenRec = record as BasicTokenRecord;
if (tokenRec != null)
{
// Save the token representing the operation
op = tokenRec.getToken();
continue;
}
if (record is ExpressionRecord)
{
expressions.AddLast(record as ExpressionRecord);
}
else
{
errors.Add(string.Format("Grammar error: record {0} at line {1} is not allowed during an arithmetic expression validation", record.recordType.ToString(), lastToken.getLine()));
}
}
ExpressionRecord type1 = expressions.Last.Value;
ExpressionRecord type2 = expressions.First.Value;
// Ensure that both expressions are integers
if (type1.GetExpressionType() != AddTypeToList.intClass || type2.GetExpressionType() != AddTypeToList.intClass)
{
errors.Add(string.Format("Cannot perform arithmetic operation at line {0} between factors of type {1} and {2}"
, lastToken.getLine(), type1.GetExpressionType().getName(), type2.GetExpressionType().getName()));
}
SymbolTable currentScope = symbolTable.Peek();
string outAddress = string.Empty;
if (currentScope.getParent() == null)
{
errors.Add(string.Format("Cannot perform an arithemetic operation outside of a function"));
}
else if (op == TokenList.And || op == TokenList.Or)
{
// Generate an address for the result of this sub-expression
outAddress = Entry.MakeAddressForEntry(currentScope.getParent(), "arithmExpr");
// Get a unique id for the jump label
string jumpId = IDGenerator.GetNext();
// Generate the code to perform a logic "and" or "or" instead of bitwise
moonCode.AddGlobal(string.Format("{0} dw 0", outAddress));
moonCode.AddLine(currentScope.getParent().getAddress(), string.Format(@"
lw r3, {0}(r0)
lw r4, {1}(r0)
{2} r2, r3, r4
bz r2, zero_{4}
addi r2, r0, 1
sw {3}(r0), r2
j endop_{4}
zero_{4} sw {3}(r0), r0
endop_{4}
", type1.GetAddress(), type2.GetAddress(), opLists[op], outAddress, jumpId));
}
else
{
// Generate an address for the result of this sub-expression
outAddress = Entry.MakeAddressForEntry(currentScope.getParent(), "arithmExpr");
// Generate code for a mathematical or relational expression
moonCode.AddGlobal(string.Format("{0} dw 0", outAddress));
moonCode.AddLine(currentScope.getParent().getAddress(), string.Format(@"
lw r3, {0}(r0)
lw r4, {1}(r0)
{2} r2, r3, r4
sw {3}(r0), r2
", type1.GetAddress(), type2.GetAddress(), opLists[op], outAddress));
}
// Place the resulting expression on the semantic stack
semanticRecordTable.Push(new ExpressionRecord(AddTypeToList.intClass, outAddress));
return(errors);
}
