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/* sf_logb.c -- float version of s_logb.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 "fdlibm.h"
#ifdef __STDC__
float logbf(float x)
#else
float logbf(x)
float x;
#endif
{
__int32_t ix;
GET_FLOAT_WORD(ix,x);
ix &= 0x7fffffff; /* high |x| */
if(FLT_UWORD_IS_ZERO(ix)) return (float)-1.0/fabsf(x);
if(!FLT_UWORD_IS_FINITE(ix)) return x*x;
if((ix>>=23)==0) /* IEEE 754 logb */
return -126.0;
else
return (float) (ix-127);
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double logb(double x)
#else
double logb(x)
double x;
#endif
{
return (double) logbf((float) x);
}
#endif /* defined(_DOUBLE_IS_32BITS) */
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