/* ParseExpr3 - handle the BXOR operator */
static ParseTreeNode *ParseExpr3(ParseContext *c)
{
ParseTreeNode *expr, *expr2;
int tkn;
expr = ParseExpr4(c);
while ((tkn = GetToken(c)) == '^') {
expr2 = ParseExpr4(c);
if (IsIntegerLit(expr) && IsIntegerLit(expr2))
expr->u.integerLit.value = expr->u.integerLit.value ^ expr2->u.integerLit.value;
else
expr = MakeBinaryOpNode(c, OP_BXOR, expr, expr2);
}
SaveToken(c,tkn);
return expr;
}
/* ParseArrayInitializers - parse array initializers */
static void ParseArrayInitializers(ParseContext *c, VMVALUE size)
{
VMVALUE *dataPtr = (VMVALUE *)c->codeBuf;
VMVALUE *dataTop = (VMVALUE *)c->ctop;
int done = VMFALSE;
Token tkn;
FRequire(c, '{');
/* handle each line of initializers */
while (!done) {
int lineDone = VMFALSE;
/* look for the first non-blank line */
while ((tkn = GetToken(c)) == T_EOL) {
if (!GetLine(c))
ParseError(c, "unexpected end of file in initializers");
}
/* check for the end of the initializers */
if (tkn == '}')
break;
SaveToken(c, tkn);
/* handle each initializer in the current line */
while (!lineDone) {
ParseTreeNode *expr;
/* get a constant expression */
expr = ParseExpr(c);
if (!IsIntegerLit(expr))
ParseError(c, "expecting a constant expression");
/* check for too many initializers */
if (--size < 0)
ParseError(c, "too many initializers");
/* store the initial value */
if (dataPtr >= dataTop)
ParseError(c, "insufficient object data space");
*dataPtr++ = expr->u.integerLit.value;
switch (tkn = GetToken(c)) {
case T_EOL:
lineDone = VMTRUE;
break;
case '}':
lineDone = VMTRUE;
done = VMTRUE;
break;
case ',':
break;
default:
ParseError(c, "expecting a comma, right brace or end of line");
break;
}
}
}
}
/* ParseScalarInitializer - parse a scalar initializer */
static VMVALUE ParseScalarInitializer(ParseContext *c)
{
ParseTreeNode *expr = ParseExpr(c);
if (!IsIntegerLit(expr))
ParseError(c, "expecting a constant expression");
return expr->u.integerLit.value;
}
/* ParseExpr8 - handle the '<<' and '>>' operators */
static ParseTreeNode *ParseExpr8(ParseContext *c)
{
ParseTreeNode *expr, *expr2;
int tkn;
expr = ParseExpr9(c);
while ((tkn = GetToken(c)) == T_SHL || tkn == T_SHR) {
expr2 = ParseExpr9(c);
if (IsIntegerLit(expr) && IsIntegerLit(expr2)) {
switch (tkn) {
case T_SHL:
expr->u.integerLit.value = expr->u.integerLit.value << expr2->u.integerLit.value;
break;
case T_SHR:
expr->u.integerLit.value = expr->u.integerLit.value >> expr2->u.integerLit.value;
break;
default:
/* not reached */
break;
}
}
else {
int op;
switch (tkn) {
case T_SHL:
op = OP_SHL;
break;
case T_SHR:
op = OP_SHR;
break;
default:
/* not reached */
op = 0;
break;
}
expr = MakeBinaryOpNode(c, op, expr, expr2);
}
}
/* ParseVariableDecl - parse a variable declaration */
static int ParseVariableDecl(ParseContext *c, char *name, VMVALUE *pSize)
{
Token tkn;
/* parse the variable name */
FRequire(c, T_IDENTIFIER);
strcpy(name, c->token);
/* handle arrays */
if ((tkn = GetToken(c)) == '[') {
int size;
/* check for an array with unspecified size */
if ((tkn = GetToken(c)) == ']')
size = 0;
/* otherwise, parse the array size */
else {
ParseTreeNode *expr;
/* put back the token */
SaveToken(c, tkn);
/* get the array size */
expr = ParseExpr(c);
/* make sure it's a constant */
if (!IsIntegerLit(expr) || expr->u.integerLit.value <= 0)
ParseError(c, "expecting a positive constant expression");
size = expr->u.integerLit.value;
/* only one dimension allowed for now */
FRequire(c, ']');
}
/* return an array and its size */
*pSize = size;
return VMTRUE;
}
/* not an array */
else
SaveToken(c, tkn);
/* return a scalar */
return VMFALSE;
}
/* ParseConstantDef - parse a 'DEF <name> =' statement */
static void ParseConstantDef(ParseContext *c, char *name)
{
ParseTreeNode *expr;
Symbol *sym;
/* get the constant value */
expr = ParseExpr(c);
/* make sure it's a constant */
if (!IsIntegerLit(expr))
ParseError(c, "expecting a constant expression");
/* add the symbol as a global */
sym = AddGlobal(c, name, SC_CONSTANT, expr->u.integerLit.value, 0);
FRequire(c, T_EOL);
}
