tests/tcg/multiarch/float_madds.c

   1 /*
   2  * Fused Multiply Add (Single)
   3  *
   4  * Copyright (c) 2019 Linaro
   5  *
   6  * SPDX-License-Identifier: GPL-3.0-or-later
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <math.h>
  12 #include <float.h>
  13 #include <fenv.h>
  14
  15 #include "float_helpers.h"
  16
  17 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  18
  19 typedef struct {
  20     int flag;
  21     char *desc;
  22 } float_mapping;
  23
  24 float_mapping round_flags[] = {
  25     { FE_TONEAREST, "to nearest" },
  26 #ifdef FE_UPWARD
  27     { FE_UPWARD, "upwards" },
  28 #endif
  29 #ifdef FE_DOWNWARD
  30     { FE_DOWNWARD, "downwards" },
  31 #endif
  32 #ifdef FE_TOWARDZERO
  33     { FE_TOWARDZERO, "to zero" }
  34 #endif
  35 };
  36
  37
  38 static void print_inputs(float a, float b, float c)
  39 {
  40     char *a_fmt, *b_fmt, *c_fmt;
  41
  42     a_fmt = fmt_f32(a);
  43     b_fmt = fmt_f32(b);
  44     c_fmt = fmt_f32(c);
  45
  46     printf("op : %s * %s + %s\n", a_fmt, b_fmt, c_fmt);
  47
  48     free(a_fmt);
  49     free(b_fmt);
  50     free(c_fmt);
  51 }
  52
  53 static void print_result(float r, int j, int k)
  54 {
  55     char *r_fmt, *flag_fmt;
  56
  57     r_fmt = fmt_f32(r);
  58     flag_fmt = fmt_flags();
  59
  60     printf("res: %s flags=%s (%d/%d)\n", r_fmt, flag_fmt, j, k);
  61
  62     free(r_fmt);
  63     free(flag_fmt);
  64 }
  65
  66 static void do_madds(float a, float b, float c, int j, int k)
  67 {
  68     float r;
  69
  70     print_inputs(a, b, c);
  71
  72     feclearexcept(FE_ALL_EXCEPT);
  73     r = __builtin_fmaf(a, b, c);
  74
  75     print_result(r, j, k);
  76 }
  77
  78 int main(int argc, char *argv[argc])
  79 {
  80     int i, j, k, nums = get_num_f32();
  81     float a, b, c;
  82
  83     for (i = 0; i < ARRAY_SIZE(round_flags); ++i) {
  84         if (fesetround(round_flags[i].flag) != 0) {
  85             printf("### Rounding %s skipped\n", round_flags[i].desc);
  86             continue;
  87         }
  88         printf("### Rounding %s\n", round_flags[i].desc);
  89         for (j = 0; j < nums; j++) {
  90             for (k = 0; k < 3; k++) {
  91                 a = get_f32(j + ((k)%3));
  92                 b = get_f32(j + ((k+1)%3));
  93                 c = get_f32(j + ((k+2)%3));
  94                 do_madds(a, b, c, j, k);
  95             }
  96         }
  97
  98         /* From https://bugs.launchpad.net/qemu/+bug/1841491 */
  99         printf("# LP184149\n");
 100         do_madds(0x1.ffffffffffffcp-1022, 0x1.0000000000001p-1, 0x0.0000000000001p-1022, j, 0);
 101         do_madds(0x8p-152, 0x8p-152, 0x8p-152, j+1, 0);
 102     }
 103
 104     return 0;
 105 }