#!/usr/bin/perl
################################################################################
#
#                         Coypright (C) 2004 Aviral Mittal.
#
#    All rights reserved. Reproducion in whole or in part is prohibited without
#    written consent of copyright Owner.The professional use of this material
#    is subject to the copy right owners approval in written.
#
################################################################################
#
#                    Comments welcome on avimit@yahoo.com
#                    Visit http://www.vlsiip.com for more free stuff
#
################################################################################
# Revision History
# This is version 2.0 Initial Revision released on 07 July 2004
################################################################################
# Changes w.r.t prev release
# 'Notes' are added 
################################################################################
# Notes:
# This perl script converts a binary number into a fixed point decimal number.
# The binary number is assumed to be representing the part of the fixed point
# Decimal number following the '.'. For example if a fixed point decimal number 
# is written as abcd.wxyz, then the part .wxyz is what this script is producing.
#
# Example Usage: unix> ./bin2point.pl 111001 \n";
# This will produce a result as 0.890625
################################################################################

if(@ARGV[0] eq "") {
  print "\n";
  print "*************************************************************\n";
  print "This program converts an binary string into fractional number\n";
  print "The input and outputs are as per Fixed Point Format Representation\n";
  print "The input string, which is a string of 0s and 1s is interpreted\n";
  print "as a fractional number. The output will be therefore of the \n";
  print "Form 0.xxxxxx whre 0.xxxxx = binary input string\n";
  print "For example 0.890625 = 111001 \n";
  print "0.890625 = 0.5*1 + 0.25*1 + 0.125*1 + 0.0625*0 + 0.03125*0 + ";
  print "0.015625*1\n";
  print "               -        -         -          -           -   ";
  print "         -\n";
  print "*************************************************************\n";
  print "\n";
  print "ERROR: insufficient fields\n";
  print "Example Usage: unix> ./bin2point.pl 10101010 \n";
  print "\n";
  exit;
}

  # print "ARGV0 = $ARGV[0]\n";
  $len = length($ARGV[0]);
  @bin = split(//,$ARGV[0]);
  # print "bin = @bin\n";
  # print "len = $len\n";

  $error = '0';
  foreach $ele(@bin) {
    if($ele eq 1 || $ele eq 0) {
       #print "OK\n";
    }# if($ele == '1' || $ele == '0')
    else {
      $error = '1';
    }
  }# foreach $ele(@bin)

  if($error == '0') {
    $i = 0;
    $frac_out = 0.0;
    $poof2 = 0.0;
    while ($i<$len) {
      $poof2 = 1/2**($i+1);
      #print "poof2 = $poof2\n";
      #print "bini = $bin[$i]\n";
      $frac_out = $frac_out + $poof2*$bin[$i];
      $i++;
    }
      print "$frac_out\n";
  }# if($error == '0')
  else {
    print "\n";
    print "*************************************************************\n";
    print "This program converts an binary string into fractional number\n";
    print "*************************************************************\n";
    print "\n";
    print "Error! Input Not Correct.";
    print "Binary String composed of 0s and/or 1s expected\n";
    print "Example Usage: unix> ./bin2point.pl 10101010 \n";
    print "0.6640625\n";
    print "*************************************************************\n";
    print "\n";
  }# else of if($error == '0')