/* Pushes local variable var node on top of the stack */
int varToStack(astNode* varNode, symTab* symtab) {
char* id = varNode->leftMostChild->id;
symbol* sym = seekExecutionLocal(id, symtab);
if(sym == NULL) {
sym = seekExecutionGlobal(id, symtab);
if(sym == NULL) {
printf("\n\nVAR DUMPED %s \n\n", id);
return -1;
}
else {
int offset = offsetVariable(varNode);
if(offset < 0)
return -1;
fprintf(yyoutasm, "\tla\t$t0, %s\t# Load address of %s into $t0\n", id+1, id+1);
fprintf(yyoutasm, "\tlw\t$t0, %d($t0)\t# Load value of %s[%d] into $t0\n", offset*4, id+1, offset);
pushStackReg("$t0", symtab);
return 0;
}
}
int offset = offsetVariable(varNode);
if(offset < 0)
return -1;
if(sym->scope == S_ARG)
fprintf(yyoutasm, "\tlw\t$t0, %d($sp)\t# Load value of %s[%d] into $t0\n", (symtab->sp-(sym->address+offset+1))*4, id, offset);
else
fprintf(yyoutasm, "\tlw\t$t0, %d($sp)\t# Load value of %s[%d] into $t0\n", (symtab->sp-(sym->address+offset+1)-3)*4, id, offset);
pushStackReg("$t0", symtab);
return 0;
}
void offsetVariable(t_tree node, int formal, int local)
{
if (node == NULL)
return;
if (node->Node.Variable.VarKind == kFormal)
offsetFormal(node, &formal);
else
offsetLocal(node, &local);
offsetVariable(node->Node.Variable.Next, formal, local);
}
void codeGenAffect(astNode* root, symTab* symtab) {
astNode* child = root->leftMostChild;
fprintf(yyoutasm, "\t## Affectation\n");
if(child != NULL && child->rightSibling != NULL && child->rightSibling->type == EXPR) {
short offset = offsetVariable(child);
if(offset >= 0) {
if(computeExpression(child->rightSibling, symtab) >= 0) { // Compute expression pushes result on the stack
stackToVar(child->leftMostChild->id, offset, symtab); // Pop stack to variable
}
}
}
fprintf(yyoutasm, "\t## End affectation\n");
}
void offsetFunction(t_tree node)
{
if (node == NULL)
return;
scope = FindId(node->Node.Function.Name, scope);
// go through var list and calc offsets..
// formals start at offset 2 and locals start at offset 0
offsetVariable(node->Node.Function.Variables, 2, 0);
scope = scope->parent;
offsetFunction(node->Node.Function.Next);
}
