Last change
on this file since 388 was 388, checked in by coas-nagasima, 5 years ago |
Azure IoT Hub Device C SDK を使ったサンプルの追加
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Property svn:eol-style
set to
native
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Property svn:keywords
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Id
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Property svn:mime-type
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text/x-csrc
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File size:
438 bytes
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[388] | 1 | #include <limits.h>
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| 2 | #include "libm.h"
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| 3 |
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| 4 | int ilogbf(float x)
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| 5 | {
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| 6 | #pragma STDC FENV_ACCESS ON
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| 7 | union {float f; uint32_t i;} u = {x};
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| 8 | uint32_t i = u.i;
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| 9 | int e = i>>23 & 0xff;
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| 10 |
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| 11 | if (!e) {
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| 12 | i <<= 9;
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| 13 | if (i == 0) {
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| 14 | FORCE_EVAL(0/0.0f);
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| 15 | return FP_ILOGB0;
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| 16 | }
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| 17 | /* subnormal x */
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| 18 | for (e = -0x7f; i>>31 == 0; e--, i<<=1);
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| 19 | return e;
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| 20 | }
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| 21 | if (e == 0xff) {
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| 22 | FORCE_EVAL(0/0.0f);
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| 23 | return i<<9 ? FP_ILOGBNAN : INT_MAX;
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| 24 | }
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| 25 | return e - 0x7f;
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| 26 | }
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