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Re: [Tinycc-devel] Buggy left shift on x86_64
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From: |
Vincent Lefevre |
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Subject: |
Re: [Tinycc-devel] Buggy left shift on x86_64 |
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Date: |
Tue, 13 Mar 2012 17:02:24 +0100 |
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User-agent: |
Mutt/1.5.21-6201-vl-r48020 (2011-12-20) |
On 2012-03-13 16:49:37 +0100, Vincent Lefevre wrote:
> FYI, the problem occurs for shift counts from 32 to 63 (larger
> shift counts are invalid in C, since the variable is on 64 bits).
The bug disappears when I replace 1UL by: (unsigned long) 1
And the bug occurs with:
m = (1UL << (SH/2)) * (1UL << (SH/2));
So, it seems that the problem is not the left shift, but the fact
that tcc does not regard 1UL as an unsigned long (64 bits).
--
Vincent Lefèvre <address@hidden> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)