none/tests/s390x/rounding-2.c

   1 #include <assert.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include "opcodes.h"
   5
   6 /* Basic test that we can set the rounding mode in the FPC and
   7    query it. Covers only generally available rounding modes. */
   8
   9 void
  10 set_rounding_mode(unsigned mode)
  11 {
  12    register unsigned r asm("1") = mode;
  13    __asm__ volatile ( SFPC(1) : : "d"(r) );
  14 }
  15
  16 unsigned
  17 get_rounding_mode(void)
  18 {
  19    unsigned fpc;
  20
  21    __asm__ volatile ("stfpc  %0" : "=Q"(fpc));
  22
  23    return fpc & 0x7;
  24 }
  25
  26
  27 int main(void)
  28 {
  29    int i;
  30    const unsigned rmodes[] = { 0, 1, 2, 3 };
  31
  32    printf("initial rounding mode: %u\n", get_rounding_mode());
  33
  34    for (i = 0; i < sizeof rmodes / sizeof rmodes[0]; ++i) {
  35       printf("setting rounding mode to %u\n", rmodes[i]);
  36       set_rounding_mode(rmodes[i]);
  37       printf("...checking: %u\n", get_rounding_mode());
  38    }
  39
  40    return 0;
  41 }