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| | #include <fenv.h>
#include <limits.h>
#include <math.h>
#include "libm.h"
int ilogbf(float x)
{
#pragma STDC FENV_ACCESS ON
union {float f; uint32_t i;} u = {x};
uint32_t i = u.i;
int e = i>>23 & 0xff;
if (x == 0.0) {
feraiseexcept(FE_INVALID);
return INT_MIN;
}
if (isinf(x)) {
feraiseexcept(FE_INVALID);
return INT_MAX;
}
if (!e) {
i <<= 9;
if (i == 0) {
FORCE_EVAL(0/0.0f);
return FP_ILOGB0;
}
/* subnormal x */
for (e = -0x7f; i>>31 == 0; e--, i<<=1);
return e;
}
if (e == 0xff) {
FORCE_EVAL(0/0.0f);
return i<<9 ? FP_ILOGBNAN : INT_MAX;
}
return e - 0x7f;
}
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