1#include <limits.h>
2#include "libm.h"
3
4int ilogbf(float x)
5{
6 #pragma STDC FENV_ACCESS ON
7 union {float f; uint32_t i;} u = {x};
8 uint32_t i = u.i;
9 int e = i>>23 & 0xff;
10
11 if (!e) {
12 i <<= 9;
13 if (i == 0) {
14 FORCE_EVAL(0/0.0f);
15 return FP_ILOGB0;
16 }
17 /* subnormal x */
18 for (e = -0x7f; i>>31 == 0; e--, i<<=1);
19 return e;
20 }
21 if (e == 0xff) {
22 FORCE_EVAL(0/0.0f);
23 return i<<9 ? FP_ILOGBNAN : INT_MAX;
24 }
25 return e - 0x7f;
26}