none/tests/s390x/mvc.c

   1 #include <stdio.h>
   2 #include <assert.h>
   3 #include <string.h>
   4
   5 char buffer[] = "0123456789abcdefXXXXX";
   6 char target[] = "---------------------";
   7 char overlap[]= "012345678901234567890";
   8 char full[300];
   9
  10 int 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    printf("\n");
  61
  62    /* Move inverse (mvcin) */
  63    printf("------- Move inverse 17 bytes from BUFFER to TARGET\n");
  64    printf("before: target = |%s|\n", target);
  65    asm volatile( "mvcin 0(17,%0),0(%1)\n"
  66                  ::"a" (target),"a" (buffer + 16): "memory");
  67    printf("after:  target = |%s|\n", target);
  68    return 0;
  69 }