| 1 | /* |
| 2 | * Fused Multiply Add (Single) |
| 3 | * |
| 4 | * Copyright (c) 2019, 2024 Linaro |
| 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0-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 | flag_fmt = fmt_flags(); |
| 58 | r_fmt = fmt_f32(r); |
| 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 | } |