/*
* Method assumes preprocessor came
* in and dealt with labels and directives.
*/
public bool Derive(Token[] tokens)
{
DTree curchild = null, tempchild = null;
Token curtoken;
string nmemonic = null;
string iden;
int i = 0;
next = null;
children = null;
if (tokens.Length == 0)
{
return(true);
}
curtoken = tokens[0];
if (curtoken.id != TokenKind.IDENTIFIER)
{
return(SyntaxErr());
}
iden = ((IdentifierToken)curtoken).identifier.ToUpper();
if (NmemonicTree.IsNmemonic(iden))
{
children = new NmemonicTree(iden);
curchild = children;
i = 1;
nmemonic = iden;
}
else
{
return(SyntaxErr());
}
while (i < tokens.Length)
{
curtoken = tokens[i];
switch (curtoken.id)
{
case TokenKind.IDENTIFIER:
iden = ((IdentifierToken)curtoken).identifier.ToUpper();
if (RegTree.IsReg(iden))
{
/*
* C is a register and also a condition.
* To solve this ambiguity, if the nmemonic requires
* a condition, it doesn't require a register, so create
* a new register tree iff the nmemonic is not conditional.
*/
if (NmemonicTree.IsConditionalNmemonic(nmemonic) &&
iden.Equals("C"))
{
tempchild = new ConditionTree("C");
}
else
{
tempchild = new RegTree(iden);
}
}
else if (NormPairTree.IsNormPair(iden))
{
tempchild = new NormPairTree(iden);
}
else if (SpecPairTree.IsSpecPair(iden))
{
tempchild = new SpecPairTree(iden);
}
else if (ConditionTree.IsCondition(iden))
{
tempchild = new ConditionTree(iden);
}
else if (SpecRegTree.IsSpecReg(iden))
{
tempchild = new SpecRegTree(iden);
}
else if (IRegTree.IsIReg(iden))
{
tempchild = new IRegTree(iden);
}
else if (IPairTree.IsIPair(iden))
{
tempchild = new IPairTree(iden);
}
else
{
return(SyntaxErr());
}
curchild.next = tempchild;
curchild = tempchild;
i++;
break;
case TokenKind.NUMBER:
tempchild = new ImmTree(((NumberToken)curtoken).number);
curchild.next = tempchild;
curchild = tempchild;
i++;
break;
case TokenKind.OPERATOR:
OperatorKind op = ((OperatorToken)curtoken).op;
switch (op)
{
case OperatorKind.LPAREN:
int start = i;
Token[] adrtokens;
i++;
while (i < tokens.Length)
{
curtoken = tokens[i];
if (curtoken.id == TokenKind.OPERATOR &&
((OperatorToken)curtoken).op
== OperatorKind.RPAREN)
{
break;
}
i++;
}
if (i >= tokens.Length)
{
return(SyntaxErr());
}
adrtokens = new Token[i - start - 1];
Array.Copy(tokens, start + 1,
adrtokens, 0, adrtokens.Length);
tempchild = new AdrTree();
bool success = ((AdrTree)tempchild).
FormAdrTree(adrtokens, start + 1);
if (!success)
{
return(false);
}
curchild.next = tempchild;
curchild = tempchild;
i++;
break;
case OperatorKind.PLUS:
if (i >= tokens.Length - 1)
{
return(SyntaxErr());
}
Token numtokenadd = tokens[i + 1];
if (numtokenadd.id != TokenKind.NUMBER)
{
return(SyntaxErr());
}
tempchild = new ImmTree(((NumberToken)numtokenadd).number);
curchild.next = tempchild;
curchild = tempchild;
i += 2;
break;
case OperatorKind.MINUS:
if (i >= tokens.Length - 1)
{
return(SyntaxErr());
}
Token numtokensub = tokens[i + 1];
if (numtokensub.id != TokenKind.NUMBER)
{
return(SyntaxErr());
}
tempchild = new ImmTree(-((NumberToken)numtokensub).number);
curchild.next = tempchild;
curchild = tempchild;
i += 2;
break;
default:
return(SyntaxErr());
}
break;
default:
break;
}
if (i < tokens.Length)
{
curtoken = tokens[i];
if (curtoken.id != TokenKind.OPERATOR ||
((OperatorToken)curtoken).op != OperatorKind.COMMA)
{
return(SyntaxErr());
}
i++;
if (i >= tokens.Length)
{
return(SyntaxErr());
}
}
}
return(true);
}
public static void DebugTree(DTree t, int indent)
{
StringBuilder sb = new StringBuilder(indent);
DTree child;
for (int i = 0; i < indent; i++)
{
sb.Append(' ');
}
switch (t.kind)
{
case DTKind.NMEMONIC:
NmemonicTree nm = (NmemonicTree)t;
Console.Write(sb);
Console.WriteLine("(NMEMONIC) { " + nm.nmemonic + " }");
break;
case DTKind.OPERATOR:
OperatorTree op = (OperatorTree)t;
Console.Write(sb);
Console.WriteLine("(OPERATOR) { " + op.op + " }");
break;
case DTKind.REG:
RegTree reg = (RegTree)t;
Console.Write(sb);
Console.WriteLine("(REGISTER) { " + reg.reg + " }");
break;
case DTKind.NORMPAIR:
NormPairTree npair = (NormPairTree)t;
Console.Write(sb);
Console.WriteLine("(NORMPAIR) { " + npair.normpair + " }");
break;
case DTKind.SPECPAIR:
SpecPairTree spair = (SpecPairTree)t;
Console.Write(sb);
Console.WriteLine("(SPECPAIR) { " + spair.specpair + " }");
break;
case DTKind.IPAIR:
IPairTree ipair = (IPairTree)t;
Console.Write(sb);
Console.WriteLine("(IPAIR) { " + ipair.ipair + " }");
break;
case DTKind.IMM:
ImmTree imm = (ImmTree)t;
Console.Write(sb);
Console.WriteLine("(IMM) { " + imm.immediate + " }");
break;
case DTKind.ADR:
AdrTree adr = (AdrTree)t;
child = adr.children;
Console.Write(sb);
Console.WriteLine("(ADR) {");
while (child != null)
{
DebugTree(child, indent + 4);
child = child.next;
}
Console.Write(sb);
Console.WriteLine("}");
break;
case DTKind.INSTRUCTION:
InstructionTree inst = (InstructionTree)t;
child = inst.children;
Console.Write(sb);
Console.WriteLine("(INSTRUCTION) {");
while (child != null)
{
DebugTree(child, indent + 4);
child = child.next;
}
Console.Write(sb);
Console.WriteLine("}");
break;
case DTKind.CONDITION:
ConditionTree cond = (ConditionTree)t;
Console.Write(sb);
Console.WriteLine("(CONDITION) { " + cond.cond + " }");
break;
case DTKind.SPECREG:
SpecRegTree specreg = (SpecRegTree)t;
Console.Write(sb);
Console.WriteLine("(SPECREG) { " + specreg.reg + " }");
break;
default:
break;
}
}