#!/usr/bin/perl

use strict;
use warnings;

#assume each value is a perl var masked to lower 8 bits

foreach (0x85, 0x05)
{
   my $x = $_;               #allow mod of $x in loop
   
   my $neg = $x & 0x80;                #decide if negative
   $x = ~$x & 0x7F, $x = -$x if $neg;  #adjust if so
     
   printf "Input=%2x hex Input=%08b decimal=%d\n", $_, $_, $x;
}   
__END__
Input=85 hex Input=10000101 decimal=-122
Input= 5 hex Input=00000101 decimal=5