/*--------------------------------------------------------------------

 *© Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *--------------------------------------------------------------------

*/

/* e_log10f.c -- float version of e_log10.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.

 * ====================================================

 */

#ifndef __SYMBIAN32__

#ifndef lint

static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_log10f.c,v 1.8 2002/05/28 18:15:04 alfred Exp $";

#endif

#endif //__SYMBIAN32__

#include <math.h>

#include "math_private.h"

static const float

two25      =  3.3554432000e+07, /* 0x4c000000 */

ivln10     =  4.3429449201e-01, /* 0x3ede5bd9 */

log10_2hi  =  3.0102920532e-01, /* 0x3e9a2080 */

log10_2lo  =  7.9034151668e-07; /* 0x355427db */

#ifdef __SYMBIAN32__

static const float zero = 0;

#else//__SYMBIAN32__

static const float zero = 0.0;

#endif//__SYMBIAN32__

EXPORT_C float

__ieee754_log10f(float x)

{

	float y,z;

	int32_t i,k,hx;

	GET_FLOAT_WORD(hx,x);

        k=0;

        if (hx < 0x00800000) {                  /* x < 2**-126  */

            if ((hx&0x7fffffff)==0)

                return -two25/zero;             /* log(+-0)=-inf */

                if (hx<0) return (x-x)/zero;        /* log(-#) = NaN */

            k -= 25; x *= two25; /* subnormal number, scale up x */

	    GET_FLOAT_WORD(hx,x);

        }

	if (hx >= 0x7f800000) return x+x;

	k += (hx>>23)-127;

	i  = ((u_int32_t)k&0x80000000)>>31;

        hx = (hx&0x007fffff)|((0x7f-i)<<23);

        y  = (float)(k+i);

	SET_FLOAT_WORD(x,hx);

	z  = y*log10_2lo + ivln10*__ieee754_logf(x);

	return  z+y*log10_2hi;

}