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     { FE_TOWARDZERO, "to zero" }
  33 };
  34
  35
  36 static void print_inputs(float a, float b, float c)
  37 {
  38     char *a_fmt, *b_fmt, *c_fmt;
  39
  40     a_fmt = fmt_f32(a);
  41     b_fmt = fmt_f32(b);
  42     c_fmt = fmt_f32(c);
  43
  44     printf("op : %s * %s + %s\n", a_fmt, b_fmt, c_fmt);
  45
  46     free(a_fmt);
  47     free(b_fmt);
  48     free(c_fmt);
  49 }
  50
  51 static void print_result(float r, int j, int k)
  52 {
  53     char *r_fmt, *flag_fmt;
  54
  55     r_fmt = fmt_f32(r);
  56     flag_fmt = fmt_flags();
  57
  58     printf("res: %s flags=%s (%d/%d)\n", r_fmt, flag_fmt, j, k);
  59
  60     free(r_fmt);
  61     free(flag_fmt);
  62 }
  63
  64 static void do_madds(float a, float b, float c, int j, int k)
  65 {
  66     float r;
  67
  68     print_inputs(a, b, c);
  69
  70     feclearexcept(FE_ALL_EXCEPT);
  71     r = __builtin_fmaf(a, b, c);
  72
  73     print_result(r, j, k);
  74 }
  75
  76 int main(int argc, char *argv[argc])
  77 {
  78     int i, j, k, nums = get_num_f32();
  79     float a, b, c;
  80
  81     for (i = 0; i < ARRAY_SIZE(round_flags); ++i) {
  82         if (fesetround(round_flags[i].flag) != 0) {
  83             printf("### Rounding %s skipped\n", round_flags[i].desc);
  84             continue;
  85         }
  86         printf("### Rounding %s\n", round_flags[i].desc);
  87         for (j = 0; j < nums; j++) {
  88             for (k = 0; k < 3; k++) {
  89                 a = get_f32(j + ((k)%3));
  90                 b = get_f32(j + ((k+1)%3));
  91                 c = get_f32(j + ((k+2)%3));
  92                 do_madds(a, b, c, j, k);
  93             }
  94         }
  95
  96         /* From https://bugs.launchpad.net/qemu/+bug/1841491 */
  97         printf("# LP184149\n");
  98         do_madds(0x1.ffffffffffffcp-1022, 0x1.0000000000001p-1, 0x0.0000000000001p-1022, j, 0);
  99         do_madds(0x8p-152, 0x8p-152, 0x8p-152, j+1, 0);
 100     }
 101
 102     return 0;
 103 }