void gen_statement(tree_t *t) {
int local_if_label;
int local_while_label;
int local_for_label;
int num_args;
if (t->type == ARRAY || t->right->type == ARRAY || t->left->type == ARRAY) {
yyerror("Array access not supported");
}
switch(t->type) {
case ASSIGNOP:
// Generate code for expression
gen_label(t->right, 1);
gen_expression(t->right);
fprintf(yyout, "\tmovl\t%%ebx, %%eax\n");
// If this is actually a return statement, then return with correct value in %eax
if(!strcmp(t->left->attribute.variable->name, top_scope->curr->name))
fprintf(yyout, "\tjmp\tsubprog%send\n", top_scope->curr->name);
else {
// Generate code for assignment
gen_assignment(t->left);
}
break;
case IF:
local_if_label = if_label++;
//Generate code for expression
gen_label(t->left, 1);
gen_expression(t->left);
//Compare and jump accordingly
fprintf(yyout, "\tcmpl\t$1, %%ebx\n\tjge\tiftrue%d\n", local_if_label);
//Generate code for else first
if (t->right->right != NULL) {
gen_statement(t->right->right);
fprintf(yyout, "\tjmp\tifend%d\n", local_if_label);
}
//Generate code for true section
fprintf(yyout, "iftrue%d:\n", local_if_label);
gen_statement(t->right->left);
fprintf(yyout, "ifend%d:\n", local_if_label);
break;
case WHILE:
local_while_label = while_label++;
//Plant label for beginning of loop
fprintf(yyout, "beginwhile%d:\n", local_while_label);
//Generate code for expression
gen_label(t->left, 1);
gen_expression(t->left);
//Compare and jump to end if needed
fprintf(yyout, "\tcmpl\t$0, %%ebx\n\tje\tendwhile%d\n", local_while_label);
//Generate code for statements
gen_statement(t->right);
fprintf(yyout, "\tjmp\tbeginwhile%d\n", local_while_label);
fprintf(yyout, "endwhile%d:\n", local_while_label);
break;
case PROCEDURE:
if (!strcmp(t->left->attribute.variable->name, "read"))
gen_read(t->right);
else if (!strcmp(t->left->attribute.variable->name, "write"))
gen_write(t->right);
else if (t->right != NULL) {
// push arguments on the stack
num_args = gen_expression_list(t->right);
fprintf(yyout, "\tcall\tsubprog%s\n", t->left->attribute.variable->name);
// move the top of the stack below args
fprintf(yyout, "\taddl\t$%d, %%esp\n", 4*num_args);
}
else {
fprintf(yyout, "\tcall\tsubprog%s\n", t->left->attribute.variable->name);
}
break;
case COMMA:
// Generate left and right statements
if (t->left->type == ARRAY || t->right->type == ARRAY)
yyerror("Array access not supported");
else {
gen_statement(t->left);
gen_statement(t->right);
}
break;
case FOR:
local_for_label = for_label++;
// Generate assignment
gen_statement(t->left->left);
//Plant label for beginning
fprintf(yyout, "forloop%d:\n", local_for_label);
// Generate expression for TO value
gen_label(t->left->right, 1);
gen_expression(t->left->right);
//Compare and jump to end if needed
if (t->left->left->left->attribute.variable->local_or_parameter == LOCAL)
fprintf(yyout, "\tcmpl\t-%i(%%ebp), %%ebx\n\tjl\tforend%d\n",
t->left->left->left->attribute.variable->offset, local_for_label);
else
fprintf(yyout, "\tcmpl\t-%i(%%ebp), %%ebx\n\tjl\tforend%d\n",
t->left->left->left->attribute.variable->offset, local_for_label);
//Generate code for statements
gen_statement(t->right);
//Increment, jump to top then plant end label
fprintf(yyout, "\tincl\t-%i(%%ebp)\n\tjmp\tforloop%d\nforend%d:\n",
t->left->left->left->attribute.variable->offset,
local_for_label, local_for_label);
break;
default:
fprintf(stderr, "TYPE: %d\n", t->type);
yywarn("Statement not supported");
break;
}
}
static void gen_statement( qli_nod* node, qli_req* request)
{
/**************************************
*
* g e n _ s t a t e m e n t
*
**************************************
*
* Functional description
* Generate BLR for statement.
*
**************************************/
if (request)
CHECK_RLB(request->req_blr);
switch (node->nod_type)
{
case nod_abort:
if (node->nod_count)
gen_expression(node->nod_arg[0], 0);
return;
case nod_assign:
gen_assignment(node, request);
return;
case nod_commit_retaining:
return;
case nod_erase:
gen_erase(node, request);
return;
case nod_for:
case nod_report_loop:
gen_for(node, request);
return;
case nod_list:
{
qli_nod** ptr = node->nod_arg;
for (const qli_nod* const* const end = ptr + node->nod_count; ptr < end; ++ptr)
{
gen_statement(*ptr, request);
}
return;
}
case nod_modify:
gen_modify(node); //, request);
return;
case nod_output:
gen_statement(node->nod_arg[e_out_statement], request);
return;
case nod_print:
gen_print_list(node->nod_arg[e_prt_list], request);
return;
case nod_repeat:
gen_statement(node->nod_arg[e_rpt_statement], request);
return;
case nod_report:
gen_report(node, request);
return;
case nod_store:
gen_store(node, request);
return;
case nod_if:
gen_if(node, request);
return;
default:
ERRQ_bugcheck(354); // Msg354 gen_statement: not yet implemented
}
}
