/* s_logbf.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 <math.h>

#include <math_private.h>

#include <libm-alias-float.h>

#include <fix-int-fp-convert-zero.h>

float

__logbf (float x)

{

  int32_t ix, rix;

  GET_FLOAT_WORD (ix, x);

  ix &= 0x7fffffff;		/* high |x| */

  if (ix == 0)

    return (float) -1.0 / fabsf (x);

  if (ix >= 0x7f800000)

    return x * x;

  if (__glibc_unlikely ((rix = ix >> 23) == 0))

    {

      /* POSIX specifies that denormal number is treated as

         though it were normalized.  */

      rix -= __builtin_clz (ix) - 9;

    }

  if (FIX_INT_FP_CONVERT_ZERO && rix == 127)

    return 0.0f;

  return (float) (rix - 127);

}

libm_alias_float (__logb, logb)