From: Paul Lutus <nospam@...>
Date: 2006-12-05T17:40:06+09:00
Subject: Re: Integer#to_s(2) works on x86, fails on x86_64

Suraj Kurapati wrote:

> Hello,
> 
> Can anyone explain why this is happening?
> 
> 
> ---- on x86_64 ----
> 
> $ ruby -v
> ruby 1.8.4 (2005-12-24) [x86_64-linux]
> 
> $ irb
>>> 2956350890592680056.to_s(2)
> RangeError: integer 2956350890592680056 too big to convert to `int'
>         from (irb):1:in `to_s'
>         from (irb):1
>         from :0
> 
> 
> ---- on x86 ----
> 
> $ ruby -v
> ruby 1.8.4 (2005-12-24) [i486-linux]
> 
> $ irb
>>> 2956350890592680056.to_s(2)
> => "10100100000111000100010111100010111001001011111011100001111000"
> 
> 
> Thanks for your consideration.

It's way too large to fit into an old-style integer of 32 bits, but it fits
with two bits to spare in a 64-bit integer. Also, in Ruby, normally an
integer too large for the Fixnum class is automatically converted to a
Bignum, so this error should not have happened.

Try this test:

32.upto(128) do |p|
  puts 2 ** p
end

See what happens on both platforms. BTW I am thinking this is an error in
the x86_64 Ruby code.

-- 
Paul Lutus
http://www.arachnoid.com