AoC day 8, Perl brute force

#!/usr/bin/perl

use strict;
use warnings;

# Registers:
my $acc = 0;
my $ip  = 0;

my %op_codes = (
    'acc' => sub { $acc += shift; $ip++ },
    'jmp' => sub { $ip  += shift },
    'nop' => sub { $ip++ },
);

my @code = map { chomp; [split] } <>;

sub toggle_op {
    my $inst = shift;

    $code[$inst][0] = ($code[$inst][0] eq 'nop') ? 'jmp' : 'nop';
}

sub run_vm {
    my $tog = shift;
    my @ran = map { 0 } (0 .. $#code);

    &toggle_op( $tog )  if ($tog != -1);

    $acc = 0;
    $ip  = 0;

    while (1) {
        last  if ($ip == $#code);
        if (++$ran[$ip] == 2) {
            &toggle_op( $tog )  if ($tog != -1);
            return (0);
        }

        &{$op_codes{ $code[$ip][0] }}( $code[$ip][1] );
    }

    return (1);
}

&run_vm( -1 );
print "Part 1: $acc\n";

foreach my $i (0 .. $#code) {
    next if ($code[$i][0] eq 'acc');

    if (&run_vm( $i )) {
        print "Part 2: $acc (swapped $i)\n";
        exit (0);
    }
}

exit (1);