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* c/9348: error in int to unsigned long multiplication on hp
@ 2003-01-17 10:36 balpreet.singh
0 siblings, 0 replies; only message in thread
From: balpreet.singh @ 2003-01-17 10:36 UTC (permalink / raw)
To: gcc-gnats
>Number: 9348
>Category: c
>Synopsis: error in int to unsigned long multiplication on hp
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: wrong-code
>Submitter-Id: net
>Arrival-Date: Fri Jan 17 02:36:00 PST 2003
>Closed-Date:
>Last-Modified:
>Originator: Balpreet Singh
>Release: 3.2.1
>Organization:
>Environment:
>Description:
multiplication of int/long values converted to unsigned long long generates wrong results.
compile the following code with gcc...
ll.c
<<
#include <stdio.h>
#define u_l_l unsigned long long
#define l_l long long
l_l mpy_res;
u_l_l mpy (long a, long b)
{
return (u_l_l) a * (u_l_l) b;
}
<<EOF
int main(void)
{
mpy_res = mpy(1,-1);
printf("dec %lld\n hex %llx\n want %llx\n", (l_l) mpy_res, (l_l) mpy_res, -1LL);
}
$>gcc ll.c
$>a.out
dec 8589934591
hex 1ffffffff
want ffffffffffffffff
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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2003-01-17 10:36 c/9348: error in int to unsigned long multiplication on hp balpreet.singh
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