none/tests/s390x/srnm.c

   1 #include <assert.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include "opcodes.h"
   5
   6 #define srnm(b,d) \
   7    ({ \
   8       __asm__ volatile ( "lghi 8," #b "\n\t" \
   9                          "srnm " #d "(8)\n\t" ::: "8"); \
  10    })
  11
  12 #define get_rounding_mode() \
  13    ({ \
  14       unsigned fpc; \
  15       __asm__ volatile ("stfpc  %0" : "=Q"(fpc)); \
  16       fpc & 0x7; \
  17    })
  18
  19 int main(void)
  20 {
  21    printf("initial rounding mode = %u\n", get_rounding_mode());
  22
  23    /* Set basic rounding modes in various ways */
  24    srnm(1,2);  // 1 + 2 = 3
  25    printf("rounding mode = %u\n", get_rounding_mode());
  26
  27    srnm(2,0);
  28    printf("rounding mode = %u\n", get_rounding_mode());
  29
  30    srnm(0,1);
  31    printf("rounding mode = %u\n", get_rounding_mode());
  32
  33    srnm(0,0);
  34    printf("rounding mode = %u\n", get_rounding_mode());
  35
  36    /* Some rounding modes with bits to be ignored */
  37    srnm(0xff,0);  // -> 3
  38    printf("rounding mode = %u\n", get_rounding_mode());
  39
  40    srnm(0,0xfe);  // -> 2
  41    printf("rounding mode = %u\n", get_rounding_mode());
  42
  43    srnm(0xf0,0x0f);  // -> 3
  44    printf("rounding mode = %u\n", get_rounding_mode());
  45
  46    return 0;
  47 }