From: Jano Svitok <jan.svitok@...>
Date: 2007-04-30T22:58:50+09:00
Subject: Re: Why is 0x7FFFFFFF Bignum and not Fixnum ?

On 4/30/07, Mr Magpie <gazmcgheesubs@yahoo.com.au> wrote:
> > Because 0x40000000 is either the sign bit or the magic flag.
>
> 0x80000000 would be the sign bit. What is this "magic flag" that seems
> to be occupying 0x40000000 ?

This is kind of "hack" / implementation detail:

this bit is a flag that distinguishes between immediate values and
full objects.
the number is either
- 31 bit signed fixnum
- nil
- true
- false
- symbol
- pointer/handle to VALUE object
For more details see
http://www.oreillynet.com/ruby/blog/2006/01/the_ruby_value_1.html