GNU bug report logs - #14879
fixnum-width, greatest-fixnum and least-fixnum disagree

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Göran Weinholt <goran <at> weinholt.se>
Subject: bug#14879: closed (Re: bug#14879: fixnum-width, greatest-fixnum
 and least-fixnum disagree)
Date: Tue, 16 Jul 2013 21:43:02 +0000

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Your bug report

#14879: fixnum-width, greatest-fixnum and least-fixnum disagree

which was filed against the guile package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 14879 <at> debbugs.gnu.org.

-- 
14879: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=14879
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

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From: Mark H Weaver <mhw <at> netris.org>
To: Göran Weinholt <goran <at> weinholt.se>
Cc: 14879-done <at> debbugs.gnu.org
Subject: Re: bug#14879: fixnum-width, greatest-fixnum and least-fixnum disagree
Date: Tue, 16 Jul 2013 17:41:41 -0400

Göran Weinholt <goran <at> weinholt.se> writes:

> scheme@(guile-user)> (import (rnrs))
> scheme@(guile-user)> (fixnum-width)
> $1 = 61
> scheme@(guile-user)> (greatest-fixnum)
> $2 = 2305843009213693951
> scheme@(guile-user)> (least-fixnum)
> $3 = -2305843009213693952
>
> If the reported fixnum width is correct, then these should be the least
> and greatest fixnums:
>
>   (- (expt 2 (- (fixnum-width) 1)))   => -1152921504606846976
>   (- (expt 2 (- (fixnum-width) 1)) 1) => 1152921504606846975
>
> If the reported least and greatest fixnums are correct, then the fixnum
> width is actually 62.

That's correct.  Fixed in 06903786211afd9a554b8f009a37111f729607ee.

    Thanks!
      Mark

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From: Göran Weinholt <goran <at> weinholt.se>
To: bug-guile <at> gnu.org
Subject: fixnum-width, greatest-fixnum and least-fixnum disagree
Date: Tue, 16 Jul 2013 16:02:55 +0200

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Hello schemers,

scheme@(guile-user)> (import (rnrs))
scheme@(guile-user)> (fixnum-width)
$1 = 61
scheme@(guile-user)> (greatest-fixnum)
$2 = 2305843009213693951
scheme@(guile-user)> (least-fixnum)
$3 = -2305843009213693952

If the reported fixnum width is correct, then these should be the least
and greatest fixnums:

  (- (expt 2 (- (fixnum-width) 1)))   => -1152921504606846976
  (- (expt 2 (- (fixnum-width) 1)) 1) => 1152921504606846975

If the reported least and greatest fixnums are correct, then the fixnum
width is actually 62.

Tested with 2.0.9.33-3bbca-dirty on an amd64 system.

Regards,

-- 
Göran Weinholt <goran <at> weinholt.se>
20             JUSTICE KENNEDY:  That seems odd.  I mean,
21 Microsoft doesn't say please buy our disk because it's
22 the prettiest disk in the business.

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