Subject: Re: Buggy BinarySearch implementation, real life and a curious soul...
From: rpw3@rpw3.org (Rob Warnock)
Date: Wed, 07 Jun 2006 23:08:36 -0500
Newsgroups: comp.lang.lisp
Message-ID: <YemdndVEHpNZPxrZnZ2dnUVZ_sidnZ2d@speakeasy.net>
Thomas A. Russ <tar@sevak.isi.edu> wrote:
+---------------
| rpw3@rpw3.org (Rob Warnock) writes:
| > Wow! Only 24-bit (signed) fixnums. That seems awfully small!
| 
| I noticed that in LispWorks/Windows as well.
| LispWorks on Unix/Mac OS X has bigger 29?-bit fixnums.
| 
| I wonder if that is an effect of the processor architecture.  Is there
| something about x86 processors that make it much less desireable to mask
| off something smaller than an entire 8-bit byte?
+---------------

I don't think so, since CMUCL & SBCL have 30-bit (signed) fixnums[1]
on 32-bit x86 platforms.


-Rob

[1] Trivia: There are technically *3* LowTag bits in a CMUCL "lispobj",
    which would ordinarily restrict fixnums to 29 bits, but fixnums
    take up both the #b000 and #b100 codepoints (for even & odd
    fixnums, resp.), which gives them a 30-bit range after all.

-----
Rob Warnock			<rpw3@rpw3.org>
627 26th Avenue			<URL:http://rpw3.org/>
San Mateo, CA 94403		(650)572-2607