A BUG of 64-bit integer addition

[PRC]

Linux kernel is:
Linux version 2.6.16.1 (address@hidden) (gcc version 4.1.1 20060525 (Red Hat 
4.1.1-1)) #1 SMP Thu Mar 22 09:22:29 CST 2007

And gawk version is:
GNU Awk 3.1.5
Copyright (C) 1989, 1991-2005 Free Software Foundation.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.


The test script is:
BEGIN {
    a1 = 0x001ffffff0426d9b
    b1 = 0x000000004392b6cc
    c1 = a1+b1
    a2 = 0xf0426d9b
    b2 = 0x4392b6cc
    c2 = a2+b2
    printf("1 -- %16x + %16x = %16x\n", a1, b1, c1);
    printf("2 -- %16x + %16x = %16x\n", a2, b2, c2);
}

The results of runing this script are:
1 --   1ffffff0426d9b +         4392b6cc =   20000033d52468
2 --         f0426d9b +         4392b6cc =        133d52467

The first calculation is wrong.

Best Regards,
PRC
Apr 17, 2008