none/tests/s390x/fixbr.c

   1 #include <assert.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <stdint.h>
   5 #include <inttypes.h>
   6 #include "opcodes.h"
   7 #include "rounding.h"
   8
   9 /* Test "fixbr"  with rounding mode given in insn (m3 field)
  10    Covers all generally available rounding modes that can be mapped to
  11    IRRoundingMode. As a consequence m3=1 which is "round to nearest with
  12    ties away from 0" is not tested here.
  13 */
  14
  15 const char *
  16 rtext(unsigned m3_round)
  17 {
  18    switch (m3_round) {
  19    case 0: return "[-> per fpc]";
  20    case 1: return "[-> nearest away]";
  21    case 3: return "[-> prepare short]";   // floating point extension fac needed
  22    case 4: return "[-> nearest even]";
  23    case 5: return "[-> 0]";
  24    case 6: return "[-> +inf]";
  25    case 7: return "[-> -inf]";
  26    }
  27    assert(0);
  28 }
  29
  30 #define round_to_int(value,round)                             \
  31 do {                                                          \
  32    long double src = value;                                   \
  33    long double dst;                                           \
  34                                                               \
  35    __asm__ volatile ("fixbr %[dst]," #round ",%[src]\n\t"     \
  36                      : [dst] "=f"(dst)                        \
  37                      : [src] "f"(src));                       \
  38                                                               \
  39    printf("fixbr %.5Lf\t-> %Lg  %s\n",                        \
  40           src, dst, rtext(round));                            \
  41 } while (0)
  42
  43 #define fixbr(value,round) round_to_int(value,round)
  44
  45 void
  46 set_rounding_mode(unsigned mode)
  47 {
  48    register unsigned r asm("1") = mode;
  49    __asm__ volatile ( SFPC(1) : : "d"(r) );
  50 }
  51
  52
  53 int main(void)
  54 {
  55    int j;
  56    static const long double dval[] = {
  57       1.25, 1.5, 2.5, 1.75, -1.25, -1.5, -2.5, -1.75, 0.0,
  58    };
  59
  60    assert(sizeof(long double) == 16);
  61
  62    /* f128 -> f128, round to int */
  63    for (j = 0; j < sizeof dval / sizeof dval[0]; ++j) {
  64       set_rounding_mode(FPC_BFP_ROUND_ZERO);
  65       fixbr(dval[j], M3_BFP_ROUND_NEAREST_EVEN);
  66       set_rounding_mode(FPC_BFP_ROUND_NEAREST_EVEN);
  67       fixbr(dval[j], M3_BFP_ROUND_ZERO);
  68       fixbr(dval[j], M3_BFP_ROUND_POSINF);
  69       fixbr(dval[j], M3_BFP_ROUND_NEGINF);
  70    }
  71
  72    return 0;
  73 }