asmtidy.pl

#!/usr/bin/env perl

use strict;
use warnings;

# Lines that start with any of these words will be left-aligned
# Also lines that are labels or comments or empty
# Anything else will be indented by exactly one tab
my @leftwords = qw(
  segment
  global
);

my $leftwords = join '|', @leftwords;
my $leftcheck = qr/^($|;|\w+:|$leftwords)/;

while (my $line = <>) {
  $line =~ s/^\s+//;
  $line =~ s/\s+$//;

  my $indent = ($line =~ $leftcheck) ? 0 : 1;

  print +("\t" x $indent), $line, "\n";
}