my $p = join '|', map { "$pre[$_]\\0{@{[($N-$_)>>3]}}$suf[($N-$_)&0x7]" } 0..7;

##</code><code>##

my $p = join '|', map { "$pre[$_](\\0{@{[($N-$_)>>3]}}$suf[($N-$_)&0x7])" } 0..7;

##</code><code>##

$-[$#-]*8 - $#- + 1