1#include <stdio.h>
2#include <assert.h>
3#include <string.h>
4
5char buffer[] = "0123456789abcdefXXXXX";
6char target[] = "---------------------";
7char overlap[]= "012345678901234567890";
8char full[300];
9
10int main(void)
11{
12   int i;
13
14   /* Normal copy */
15   printf("------- Copy 17 bytes from BUFFER to TARGET\n");
16   printf("before: buffer = |%s|\n", buffer);
17   printf("before: target = |%s|\n", target);
18   asm volatile( "mvc 0(17,%0),0(%1)\n"
19                 ::"a" (target),"a" (buffer): "memory");
20   printf("after:  buffer = |%s|\n", buffer);
21   printf("after:  target = |%s|\n", target);
22   printf("\n");
23
24   /* Destructive overlap #1 */
25   printf("------- Destructive overlap #1\n");
26   printf("before: |%s|\n", overlap);
27   asm volatile( "mvc 1(17,%0),0(%1)\n"
28                 ::"a" (overlap),"a" (overlap): "memory");
29   printf("after:  |%s|\n", overlap);
30
31   /* Destructive overlap #2 */
32   printf("------- Destructive overlap #2\n");
33   memset(target, '-', sizeof target - 1);  // restore initial state
34   printf("before: target = |%s|\n", target);
35   asm volatile( "mvi 0(%0),'x'\n\t"        // target[1] = 'x'
36                 "mvc 1(2,%0),0(%0)\n\t"    // target[2:3] = target[1]
37                 :: "a" (target+1));
38   printf("after:  target = |%s|\n", target);
39
40   /* Destructive overlap #3 */
41   printf("------- Destructive overlap #3 (max length)\n");
42   memset(full, '-', sizeof full);
43   full[0] = 'x';
44   asm volatile( "mvc 1(256,%0),0(%0)\n\t"     // full[1:256] = full[0]
45                 :: "a" (full));
46   /* Verify: the first 256+1 characters should be 'x' followed by '-' */
47   for (i = 0; i <= 256; ++i)
48      assert(full[i] == 'x');
49   for ( ; i < sizeof full; ++i)
50      assert(full[i] == '-');
51   printf("\n");
52
53   /* Non-destructive overlap */
54   printf("------- Non-destructive overlap  buf[0:4] = buf[10:14]\n");
55   char buf[] = "0123456789abcde";
56   printf("before: buf = |%s|\n", buf);
57   asm volatile( "mvc 0(5,%0),10(%1)\n"
58                 ::"a" (buf),"a" (buf): "memory");
59   printf("after:  buf = |%s|\n", buf);
60
61   return 0;
62}
63