xref: /freebsd-10.2-release/sys/cddl/boot/zfs/fletcher.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*#pragma ident	"%Z%%M%	%I%	%E% SMI"*/

static void
fletcher_2_native(const void *buf, uint64_t size, zio_cksum_t *zcp)
{
	const uint64_t *ip = buf;
	const uint64_t *ipend = ip + (size / sizeof (uint64_t));
	uint64_t a0, b0, a1, b1;

	for (a0 = b0 = a1 = b1 = 0; ip < ipend; ip += 2) {
		a0 += ip[0];
		a1 += ip[1];
		b0 += a0;
		b1 += a1;
	}

	ZIO_SET_CHECKSUM(zcp, a0, a1, b0, b1);
}

static void
fletcher_2_byteswap(const void *buf, uint64_t size, zio_cksum_t *zcp)
{
	const uint64_t *ip = buf;
	const uint64_t *ipend = ip + (size / sizeof (uint64_t));
	uint64_t a0, b0, a1, b1;

	for (a0 = b0 = a1 = b1 = 0; ip < ipend; ip += 2) {
		a0 += BSWAP_64(ip[0]);
		a1 += BSWAP_64(ip[1]);
		b0 += a0;
		b1 += a1;
	}

	ZIO_SET_CHECKSUM(zcp, a0, a1, b0, b1);
}

static void
fletcher_4_native(const void *buf, uint64_t size, zio_cksum_t *zcp)
{
	const uint32_t *ip = buf;
	const uint32_t *ipend = ip + (size / sizeof (uint32_t));
	uint64_t a, b, c, d;

	for (a = b = c = d = 0; ip < ipend; ip++) {
		a += ip[0];
		b += a;
		c += b;
		d += c;
	}

	ZIO_SET_CHECKSUM(zcp, a, b, c, d);
}

static void
fletcher_4_byteswap(const void *buf, uint64_t size, zio_cksum_t *zcp)
{
	const uint32_t *ip = buf;
	const uint32_t *ipend = ip + (size / sizeof (uint32_t));
	uint64_t a, b, c, d;

	for (a = b = c = d = 0; ip < ipend; ip++) {
		a += BSWAP_32(ip[0]);
		b += a;
		c += b;
		d += c;
	}

	ZIO_SET_CHECKSUM(zcp, a, b, c, d);
}