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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) */