=head1 Loops

PIR has no built-in looping structures such as C<for>, C<while>,
C<repeat> or C<until>.  All loops are built by using conditionals
and C<goto>.

The loop below calculates 5 factorial, stored in C<$I0>.  C<$I1>
is the loop counter.

=cut

.sub main :main

    $I0 = 1               # product
    $I1 = 5               # counter

  REDO:                   # start of loop
    $I0 = $I0 * $I1
    dec $I1
    if $I1 > 0 goto REDO  # end of loop

    print $I0
    print "\n"

.end

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