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/* sf_ilogb.c -- float version of s_ilogb.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include <limits.h>
#include "fdlibm.h"
#ifdef __STDC__
int ilogbf(float x)
#else
int ilogbf(x)
float x;
#endif
{
__int32_t hx,ix;
GET_FLOAT_WORD(hx,x);
hx &= 0x7fffffff;
if(FLT_UWORD_IS_ZERO(hx))
return FP_ILOGB0; /* ilogb(0) = special case error */
if(FLT_UWORD_IS_SUBNORMAL(hx)) {
for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
return ix;
}
#if FP_ILOGBNAN != INT_MAX
else if (FLT_UWORD_IS_NAN(hx)) return FP_ILOGBNAN; /* NAN */
#endif
else if (!FLT_UWORD_IS_FINITE(hx)) return INT_MAX;
else return (hx>>23)-127;
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
int ilogb(double x)
#else
int ilogb(x)
double x;
#endif
{
return ilogbf((float) x);
}
#endif /* defined(_DOUBLE_IS_32BITS) */
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