You can get by with just one sorting routine by reversing the arguments as needed.

$ perl -Mstrict -wle '
> my @arr = qw{ q w e r t y u i o p };
> my $sc  = sub { my( $a, $b ) = @_; $a cmp $b };
> my $rev = 0;
> my @asc = sort { $rev ? $sc->( $b, $a ) : $sc->( $a, $b) } @arr;
> $rev    = 1; 
> my @des = sort { $rev ? $sc->( $b, $a ) : $sc->( $a, $b) } @arr;
> print qq{@arr\n@asc\n@des};'
q w e r t y u i o p
e i o p q r t u w y
y w u t r q p o i e
$
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I hope this is of interest.