#!/usr/bin/perl

# PDP-8 floating point constants are exponent and
# mantissa, where mantissa is between 1/2 and one 
# (but not exactly one) or zero.

# The first word is the signed exponent (power of 2), 
# and the subsequent 2 (or more) words are the signed 
# mantissa.

@bits = @ARGV;
$exp = oct(shift @bits);
$exp = $exp - 4096 if $exp > 2047;
$exp += 1;

$bits = 0;
$first = 1;
$minus = 0;
foreach $b (@bits) {
  $d = oct($b);
  if ($first && ($d > 2047)) {
    $minus = 1;
  }
  $d = ~$d & 07777 if $minus;
  $bits = ($bits << 12) + $d;
  $exp -= 12;
  $first = 0;
}
$bits++ if $minus;

print "-" if $minus;
printf "%f", (0.0 + $bits) * 2**$exp;