/*      $NetBSD: n_log2.c,v 1.2 2024/07/16 14:52:50 riastradh Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Martin Husemann <[email protected]>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: n_log2.c,v 1.2 2024/07/16 14:52:50 riastradh Exp $");

/* LOG2(X)
* RETURN THE BASE 10 LOGARITHM OF x
*
* Required kernel function:
*      log(x)
*
* Method :
*                          log(x)
*              log2(x) =  ---------
*                          log(2)
*/

#include "namespace.h"

#define _LIBM_STATIC
#include "mathimpl.h"

__weak_alias(log2l, _log2l)
__strong_alias(_log2l, _log2)

static const double ln2 = .6931471805599453094172321214581765680755;

__weak_alias(log2, _log2)
double
log2(double x)
{
       return log(x)/ln2;
}

__weak_alias(log2f, _log2f)
float
log2f(float x)
{
       return logf(x)/ln2;
}