source:
asp3_tinet_ecnl_rx/trunk/musl-1.1.18/src/math/coshf.c
Last change on this file was 337, checked in by , 6 years ago | |
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File size: 492 bytes |
Rev | Line | |
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[337] | 1 | #include "libm.h" |
2 | ||
3 | float coshf(float x) | |
4 | { | |
5 | union {float f; uint32_t i;} u = {.f = x}; | |
6 | uint32_t w; | |
7 | float t; | |
8 | ||
9 | /* |x| */ | |
10 | u.i &= 0x7fffffff; | |
11 | x = u.f; | |
12 | w = u.i; | |
13 | ||
14 | /* |x| < log(2) */ | |
15 | if (w < 0x3f317217) { | |
16 | if (w < 0x3f800000 - (12<<23)) { | |
17 | FORCE_EVAL(x + 0x1p120f); | |
18 | return 1; | |
19 | } | |
20 | t = expm1f(x); | |
21 | return 1 + t*t/(2*(1+t)); | |
22 | } | |
23 | ||
24 | /* |x| < log(FLT_MAX) */ | |
25 | if (w < 0x42b17217) { | |
26 | t = expf(x); | |
27 | return 0.5f*(t + 1/t); | |
28 | } | |
29 | ||
30 | /* |x| > log(FLT_MAX) or nan */ | |
31 | t = __expo2f(x); | |
32 | return t; | |
33 | } |
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