switch-coreboot/lib/clog2.c
Ronald G. Minnich 3b384ce2a2 log2 is now log2f (floor) and log2c (ceiling) and users MUST pick one or
the other. It really matters for non-power-of-2 numbers. 

This breaks k8 builds; fix is coming. 
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>


git-svn-id: svn://coreboot.org/repository/coreboot-v3@852 f3766cd6-281f-0410-b1cd-43a5c92072e9
2008-08-31 20:28:21 +00:00

84 lines
2.8 KiB
C

/*
* This file is part of the coreboot project.
*
* It is based on the file js/src/jscpucfg.c from Mozilla, CVS rev. 3.25.
* See http://lxr.mozilla.org/mozilla1.8.0/source/js/src/jscpucfg.c.
*/
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/**
* return the truncated log2 of the number.
* @param n number to take the log of
* @return log2 of the smallest integer that is a power of of 2
* and that is <= to the parameter. E.g. log2f(72) is 6.
*/
int log2f(unsigned int n)
{
int log2 = 0;
if (n >> 16)
log2 += 16, n >>= 16;
if (n >> 8)
log2 += 8, n >>= 8;
if (n >> 4)
log2 += 4, n >>= 4;
if (n >> 2)
log2 += 2, n >>= 2;
if (n >> 1)
log2++;
return log2;
}
/**
* return the log2 of the number in integer form, rounded up as needed.
* @param n number to take the log of
* @return log2 of the smallest integer that is a power of 2
* that is >= to the parameter. E.g. log2(72) is 7.
*/
int log2c(unsigned int n)
{
int log2 = 0;
if (n & (n - 1))
log2++;
return log2 + log2f(n);
}