/** execute_statement Execute a Cx statement
*
* @param p_function_id : ptr to the routine symtab node
*/
void cx_executor::execute_statement(cx_symtab_node *p_function_id) {
if (token != tc_left_bracket) {
++statement_count;
trace_statement();
}
switch (token) {
case tc_identifier:
{
if (p_node->defn.how == dc_function) {
execute_function_call(p_node);
} else {
cx_symtab_node *p_var = p_node;
get_token();
if (token_in(token, tokenlist_assign_ops)) {
execute_assignment(p_var);
} else {
execute_variable(p_var, false);
pop();
}
}
}
break;
case tc_DO: execute_DO(p_function_id);
break;
case tc_WHILE: execute_WHILE(p_function_id);
break;
case tc_IF: execute_IF(p_function_id);
break;
case tc_FOR: execute_FOR(p_function_id);
break;
case tc_SWITCH: //parse_SWITCH();
break;
case tc_CASE:
case tc_DEFAULT://parse_case_label();
break;
case tc_BREAK:
get_token();
break_loop = true;
break;
case tc_left_bracket: execute_compound(p_function_id);
break;
case tc_RETURN: execute_RETURN(p_function_id);
break;
default:
break;
}
}
/** execute_actual_parameters Execute the actual parameters of
* a declared subroutine call.
*
* @param p_function_id : ptr to the subroutine name's symtab node
*/
void cx_executor::execute_actual_parameters (cx_symtab_node *p_function_id) {
cx_symtab_node *p_formal_id; // ptr to formal parm's symtab node
// Loop to execute each actual parameter.
for (p_formal_id = p_function_id->defn.routine.locals.p_parms_ids;
p_formal_id;
p_formal_id = p_formal_id->next__) {
cx_type *p_formal_type = p_formal_id->p_type;
get_token();
/* Reference parameter: execute_variable will leave the actual
* parameter's address on top of the stack. */
if (p_formal_id->defn.how == dc_reference) {
const int size = p_node->p_type->size;
p_formal_type->form = p_node->p_type->form;
execute_variable(p_node, true);
if (p_formal_type->form == fc_array) {
p_formal_type->size = size;
p_formal_type->array.element_count = size;
p_formal_type->array.max_index = size;
p_formal_id->runstack_item = top();
} else {
p_formal_id->runstack_item = top();
}
get_token();
}// value parameter
else {
cx_type *p_actual_type = execute_expression();
if ((p_formal_type == p_float_type) &&
(p_actual_type->base_type() == p_integer_type)) {
// real formal := integer actual:
// convert integer value to real.
float ff = top()->basic_types.int__;
pop();
push(ff);
p_formal_id->runstack_item = top();
} else if (!p_formal_type->is_scalar_type()) {
/* Formal parameter is an array or a record:
* Make a copy of the actual parameter's value. */
const int size = p_actual_type->size;
void *p_target_address = nullptr;
const int num_of_elements = size / p_actual_type->base_type()->size;
p_target_address = realloc(p_target_address, size);
//memset(p_target_address, 0, size);
if (p_target_address == nullptr) {
perror("realloc");
exit(0);
}
void *p_source = top()->basic_types.addr__;
memcpy(p_target_address, p_source, size);
pop();
push(p_target_address);
p_formal_type->array.element_count = num_of_elements;
p_formal_type->array.max_index = num_of_elements;
p_formal_type->size = size;
p_formal_type->form = fc_array;
p_formal_id->runstack_item = top();
} else {
// Range check an integer or enumeration
// formal parameter.
range_check(p_formal_type, top()->basic_types.int__);
p_formal_id->runstack_item = top();
}
}
}
if (token == tc_left_paren) get_token();
}
