1 extern void abort(void);
2 extern void exit(int);
3 
4 void
5 foo (char *bp, unsigned n)
6 {
7   register char c;
8   register char *ep = bp + n;
9   register char *sp;
10 
11   while (bp < ep)
12     {
13       sp = bp + 3;
14       c = *sp;
15       *sp = *bp;
16       *bp++ = c;
17       sp = bp + 1;
18       c = *sp;
19       *sp = *bp;
20       *bp++ = c;
21       bp += 2;
22     }
23 }
24 
25 int main(void)
26 {
27   int one = 1;
28 
29   if (sizeof(int) != 4 * sizeof(char))
30     exit(0);
31 
32   foo((char *)&one, sizeof(one));
33   foo((char *)&one, sizeof(one));
34 
35   if (one != 1)
36     abort();
37 
38   exit(0);
39 }
40