c/2614: Error when calculating with long long int

Mon Apr 23 07:16:00 GMT 2001

>Number:         2614
>Category:       c
>Synopsis:       Error when calculating with long long int
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 23 07:16:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     jacob.schultz@barconet.com
>Release:        gcc-2.95.3
>Organization:
>Environment:
Linux, Cygwin
>Description:
There seems to be a problem when calculating with long longs. In a program I need to mask a number of bits from a long long, but something goes wrong. The calculation
((1<<n)-1)&m returns zero when n is 32 or larger, even if bits are set in m. Both n and m are unsigned long long int.
I've attached an example which illustrates the pwoblem.
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: