xref: /illumos-gate/usr/src/uts/sparc/os/bitmap_arch.c (revision bf16b11e)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2014 by Delphix. All rights reserved.
 */

/*
 * Architecture specific definition for bitmap related routines.
 * These may be implemented using ISA specific instructions.
 */
#include <sys/bitmap.h>

/*
 * Find highest one bit set.
 *	Returns bit number + 1 of highest bit that is set, otherwise returns 0.
 */
int
highbit64(uint64_t i)
{
	int h = 1;

	if (i == 0)
		return (0);
	if (i & 0xffffffff00000000ULL) {
		h += 32; i >>= 32;
	}
	if (i & 0xffff0000) {
		h += 16; i >>= 16;
	}
	if (i & 0xff00) {
		h += 8; i >>= 8;
	}
	if (i & 0xf0) {
		h += 4; i >>= 4;
	}
	if (i & 0xc) {
		h += 2; i >>= 2;
	}
	if (i & 0x2) {
		h += 1;
	}
	return (h);
}

/*
 * Find highest one bit set.
 *	Returns bit number + 1 of highest bit that is set, otherwise returns 0.
 * High order bit is 31 (or 63 in _LP64 kernel).
 */
int
highbit(ulong_t i)
{
	register int h = 1;

	if (i == 0)
		return (0);
#ifdef _LP64
	if (i & 0xffffffff00000000ul) {
		h += 32; i >>= 32;
	}
#endif
	if (i & 0xffff0000) {
		h += 16; i >>= 16;
	}
	if (i & 0xff00) {
		h += 8; i >>= 8;
	}
	if (i & 0xf0) {
		h += 4; i >>= 4;
	}
	if (i & 0xc) {
		h += 2; i >>= 2;
	}
	if (i & 0x2) {
		h += 1;
	}
	return (h);
}

/*
 * Find lowest one bit set.
 *	Returns bit number + 1 of lowest bit that is set, otherwise returns 0.
 * Low order bit is 0.
 */
int
lowbit(ulong_t i)
{
	register int h = 1;

	if (i == 0)
		return (0);

#ifdef _LP64
	if (!(i & 0xffffffff)) {
		h += 32; i >>= 32;
	}
#endif
	if (!(i & 0xffff)) {
		h += 16; i >>= 16;
	}
	if (!(i & 0xff)) {
		h += 8; i >>= 8;
	}
	if (!(i & 0xf)) {
		h += 4; i >>= 4;
	}
	if (!(i & 0x3)) {
		h += 2; i >>= 2;
	}
	if (!(i & 0x1)) {
		h += 1;
	}
	return (h);
}