source:
asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/math/coshf.c@
352
Last change on this file since 352 was 352, checked in by , 6 years ago | |
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File size: 492 bytes |
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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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