source:
azure_iot_hub/trunk/musl-1.1.18/src/math/exp10f.c
Last change on this file was 389, checked in by , 5 years ago | |
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File size: 579 bytes |
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1 | #define _GNU_SOURCE |
2 | #include <math.h> |
3 | #include <stdint.h> |
4 | #include "libc.h" |
5 | |
6 | float exp10f(float x) |
7 | { |
8 | static const float p10[] = { |
9 | 1e-7f, 1e-6f, 1e-5f, 1e-4f, 1e-3f, 1e-2f, 1e-1f, |
10 | 1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7 |
11 | }; |
12 | float n, y = modff(x, &n); |
13 | union {float f; uint32_t i;} u = {n}; |
14 | /* fabsf(n) < 8 without raising invalid on nan */ |
15 | if ((u.i>>23 & 0xff) < 0x7f+3) { |
16 | if (!y) return p10[(int)n+7]; |
17 | y = exp2f(3.32192809488736234787031942948939f * y); |
18 | return y * p10[(int)n+7]; |
19 | } |
20 | return exp2(3.32192809488736234787031942948939 * x); |
21 | } |
22 | |
23 | weak_alias(exp10f, pow10f); |
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