File: xor.c

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/*
 *   (C) Copyright IBM Corp. 2001, 2003
 *
 *   This program is free software;  you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Module: mdregmgr
 * File: xor.c
 *
 * Description: This file contains functions for XORing a block of data for use
 *              in calculating parity blocks in RAID4 and RAID5.
 *              This code was stolen from the kernel code in drivers/md/xor.c
 *              and include/asm-generic/xor.h.
 */

#include <plugin.h>

#include "md.h"
#include "xor.h"
#include "raid5_mgr.h"

static void
xor_8regs_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
{
	long lines = bytes / (sizeof (long)) / 8;

	do {
		p1[0] ^= p2[0];
		p1[1] ^= p2[1];
		p1[2] ^= p2[2];
		p1[3] ^= p2[3];
		p1[4] ^= p2[4];
		p1[5] ^= p2[5];
		p1[6] ^= p2[6];
		p1[7] ^= p2[7];
		p1 += 8;
		p2 += 8;
	} while (--lines > 0);
}

static void
xor_8regs_3(unsigned long bytes, unsigned long *p1, unsigned long *p2,
	    unsigned long *p3)
{
	long lines = bytes / (sizeof (long)) / 8;

	do {
		p1[0] ^= p2[0] ^ p3[0];
		p1[1] ^= p2[1] ^ p3[1];
		p1[2] ^= p2[2] ^ p3[2];
		p1[3] ^= p2[3] ^ p3[3];
		p1[4] ^= p2[4] ^ p3[4];
		p1[5] ^= p2[5] ^ p3[5];
		p1[6] ^= p2[6] ^ p3[6];
		p1[7] ^= p2[7] ^ p3[7];
		p1 += 8;
		p2 += 8;
		p3 += 8;
	} while (--lines > 0);
}

static void
xor_8regs_4(unsigned long bytes, unsigned long *p1, unsigned long *p2,
	    unsigned long *p3, unsigned long *p4)
{
	long lines = bytes / (sizeof (long)) / 8;

	do {
		p1[0] ^= p2[0] ^ p3[0] ^ p4[0];
		p1[1] ^= p2[1] ^ p3[1] ^ p4[1];
		p1[2] ^= p2[2] ^ p3[2] ^ p4[2];
		p1[3] ^= p2[3] ^ p3[3] ^ p4[3];
		p1[4] ^= p2[4] ^ p3[4] ^ p4[4];
		p1[5] ^= p2[5] ^ p3[5] ^ p4[5];
		p1[6] ^= p2[6] ^ p3[6] ^ p4[6];
		p1[7] ^= p2[7] ^ p3[7] ^ p4[7];
		p1 += 8;
		p2 += 8;
		p3 += 8;
		p4 += 8;
	} while (--lines > 0);
}

static void
xor_8regs_5(unsigned long bytes, unsigned long *p1, unsigned long *p2,
	    unsigned long *p3, unsigned long *p4, unsigned long *p5)
{
	long lines = bytes / (sizeof (long)) / 8;

	do {
		p1[0] ^= p2[0] ^ p3[0] ^ p4[0] ^ p5[0];
		p1[1] ^= p2[1] ^ p3[1] ^ p4[1] ^ p5[1];
		p1[2] ^= p2[2] ^ p3[2] ^ p4[2] ^ p5[2];
		p1[3] ^= p2[3] ^ p3[3] ^ p4[3] ^ p5[3];
		p1[4] ^= p2[4] ^ p3[4] ^ p4[4] ^ p5[4];
		p1[5] ^= p2[5] ^ p3[5] ^ p4[5] ^ p5[5];
		p1[6] ^= p2[6] ^ p3[6] ^ p4[6] ^ p5[6];
		p1[7] ^= p2[7] ^ p3[7] ^ p4[7] ^ p5[7];
		p1 += 8;
		p2 += 8;
		p3 += 8;
		p4 += 8;
		p5 += 8;
	} while (--lines > 0);
}

		
void
xor_block(unsigned int count, xorblock_t * block, unsigned long size) {
	unsigned long *p0, *p1, *p2, *p3, *p4;

	p0 = (unsigned long *) block->buf[0];
	p1 = (unsigned long *) block->buf[1];
	if (count == 2) {
		xor_8regs_2(size, p0, p1);
		return;
	}

	p2 = (unsigned long *) block->buf[2];
	if (count == 3) {
		xor_8regs_3(size, p0, p1, p2);
		return;
	}

	p3 = (unsigned long *) block->buf[3];
	if (count == 4) {
		xor_8regs_4(size, p0, p1, p2, p3);
		return;
	}

	p4 = (unsigned long *) block->buf[4];
	xor_8regs_5(size, p0, p1, p2, p3, p4);
}