#!/usr/bin/env perl

use strict;
use warnings;

{
    local $/ = "inst2\n";

    while (<DATA>) {
        /^(\w+)=\w+\s+(\w+)/;
        printf "%#x %1\$d\n" => hex($2) - hex $1;
    }
} 

__DATA__
0x405d75=inst1
0x405d7a=inst2
0x4035f7=inst1
0x4035f8=inst2
0x4035f8=inst1
0x4035fb=inst2

##</code><code>##

0x5 5
0x1 1
0x3 3