1 /*  Copyright (C) 2007 IBM
2 
3     Author: Pete Eberlein  eberlein@us.ibm.com
4 
5     This program is free software; you can redistribute it and/or
6     modify it under the terms of the GNU General Public License as
7     published by the Free Software Foundation; either version 2 of the
8     License, or (at your option) any later version.
9 
10     This program is distributed in the hope that it will be useful, but
11     WITHOUT ANY WARRANTY; without even the implied warranty of
12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13     General Public License for more details.
14 
15     You should have received a copy of the GNU General Public License
16     along with this program; if not, write to the Free Software
17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18     02111-1307, USA.
19 
20     The GNU General Public License is contained in the file COPYING.
21 */
22 
23 
24 
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <strings.h>
28 
29 #define CMPB(result,a,b) \
30     asm __volatile ("cmpb %0, %1, %2\n" : "=r"(result) : "r"(a), "r"(b))
31 
32 
main(int argc,char * argv[])33 int main(int argc, char *argv[])
34 {
35    int i, j, k;
36    long mask;
37    for (i = 1; i < 16; i++) {
38       mask = 0;
39       if (i & 1)
40          mask += 0xff;
41       if (i & 2)
42          mask += 0xff00;
43       if (i & 4)
44          mask += 0xff0000;
45       if (i & 8)
46          mask += 0xff000000;
47 
48       for (j = 0; j < 256; j++)
49          for (k = 0; k < 256; k++)
50             if (j != k) {
51 
52                long a, b, result;
53                a = (mask & (j * 0x1010101)) + ((~mask) & (k * 0x1010101));
54                b = j * 0x1010101;
55                CMPB(result, a, b);
56                if (result != mask) {
57                   printf("%llx %llx %llx %llx\n",
58                          (unsigned long long) mask, (unsigned long long) a,
59                          (unsigned long long) b,
60                          (unsigned long long) result);
61                   exit(1);
62 		}
63             }
64 
65    }
66 
67    return 0;
68 }
69