void n_for::code_gen(status& stat, std::ostream& out)
{
if (init != NULL) // initialising expression
init->code_gen(stat, out);
// start of loop: this is a lot like a while loop.
stat.set_continue_label();
out << stat.get_continue_label() << ":\n";
stat.lock_register(out);
stat.set_assign_expr();
// check expression
cond->code_gen(stat, out);
stat.set_break_label();
// exit loop if expression equals zero
out << "\tbeqz\t$t" << stat.get_register() << "," << stat.get_break_label() << "\n";
out << "\tnop\n";
stat.unlock_register(out);
stat.set_assign_expr();
// loop statement
left->code_gen(stat, out);
if (right != NULL) // loop expression (something like i++)
right->code_gen(stat, out);
out << "\tb\t" << stat.get_continue_label() << "\n";
out << "\tnop\n";
out << stat.get_break_label() << ":\n";
stat.reset_labels(true);
return;
}
void n_switch::code_gen(status& stat, std::ostream& out)
{
stat.lock_register(out);
stat.set_assign_expr();
// check expression
left->code_gen(stat, out);
stat.set_assign_expr();
stat.set_break_label();
// list of cases
right->code_gen(stat, out);
stat.unlock_register(out);
out << stat.get_break_label() << ":\n";
out << stat.get_case_label() << ":\n";
stat.reset_labels(false);
return;
}
void n_dowhile::code_gen(status& stat, std::ostream& out)
{
// label signifying the start of the loop
stat.set_continue_label();
out << stat.get_continue_label() << ":\n";
// loop statement
stat.set_break_label();
left->code_gen(stat, out);
stat.lock_register(out);
stat.set_assign_expr();
// check expression
right->code_gen(stat, out);
// do another loop if expression is non zero
out << "\tbnez\t$t" << stat.get_register() << "," << stat.get_continue_label() << "\n";
out << "\tnop\n";
out << stat.get_break_label() << ":\n";
stat.unlock_register(out);
stat.set_assign_expr();
stat.reset_labels(true);
return;
}
void n_while::code_gen(status& stat, std::ostream& out)
{
// label signifying the start of the loop
stat.set_continue_label();
out << stat.get_continue_label() << ":\n";
stat.lock_register(out);
stat.set_assign_expr();
// check expression
left->code_gen(stat, out);
stat.set_break_label();
// exit loop if expression equals zero
out << "\tbeqz\t$t" << stat.get_register() << "," << stat.get_break_label() << "\n";
out << "\tnop\n";
stat.unlock_register(out);
stat.set_assign_expr();
// loop statement
right->code_gen(stat, out);
// return to top of loop
out << "\tb\t" << stat.get_continue_label() << "\n";
out << "\tnop\n";
out << stat.get_break_label() << ":\n";
stat.reset_labels(true);
return;
}
