GNU bug report logs - #21901
bit shift wrong on maximal right shift

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Package: guile;

Reported by: Zefram <zefram <at> fysh.org>

Date: Fri, 13 Nov 2015 10:23:02 UTC

Severity: normal

Done: Mark H Weaver <mhw <at> netris.org>

Bug is archived. No further changes may be made.

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Message #13 received at 21901-done <at> debbugs.gnu.org (full text, mbox):

From: Mark H Weaver <mhw <at> netris.org>
To: Zefram <zefram <at> fysh.org>
Cc: 21901-done <at> debbugs.gnu.org
Subject: Re: bug#21901: bit shift wrong on maximal right shift
Date: Sun, 14 Oct 2018 05:40:51 -0400

Zefram <zefram <at> fysh.org> writes:

> With Guile 2.0.11:
>
> scheme@(guile-user)> (ash 123 (ash -1 63))
> $1 = 123
>
> Correct result would of course be zero.  Problem only occurs for
> exactly this shift distance: one bit less produces the right answer.

Nice catch!

It's finally fixed in commit 1990aa916382d0afcebd5315a6d6f555949ff654 on
the stable-2.2 branch.  The fix will be in Guile 2.2.5.

Thanks for the report.

      Mark
This bug report was last modified 6 years and 211 days ago.

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