source:
azure_iot_hub/trunk/musl-1.1.18/src/math/scalbnf.c
Last change on this file was 389, checked in by , 5 years ago | |
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File size: 477 bytes |
Rev | Line | |
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[388] | 1 | #include <math.h> |
2 | #include <stdint.h> | |
3 | ||
4 | float scalbnf(float x, int n) | |
5 | { | |
6 | union {float f; uint32_t i;} u; | |
7 | float_t y = x; | |
8 | ||
9 | if (n > 127) { | |
10 | y *= 0x1p127f; | |
11 | n -= 127; | |
12 | if (n > 127) { | |
13 | y *= 0x1p127f; | |
14 | n -= 127; | |
15 | if (n > 127) | |
16 | n = 127; | |
17 | } | |
18 | } else if (n < -126) { | |
19 | y *= 0x1p-126f * 0x1p24f; | |
20 | n += 126 - 24; | |
21 | if (n < -126) { | |
22 | y *= 0x1p-126f * 0x1p24f; | |
23 | n += 126 - 24; | |
24 | if (n < -126) | |
25 | n = -126; | |
26 | } | |
27 | } | |
28 | u.i = (uint32_t)(0x7f+n)<<23; | |
29 | x = y * u.f; | |
30 | return x; | |
31 | } |
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