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/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
*
* 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, Inc., 53 Temple Place Ste 330,
* Boston MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* raid6int1.c
*
* 1-way unrolled portable integer math RAID-6 instruction set
*
* This file was postprocessed using unroll.pl and then ported to userspace
*/
#include <stdint.h>
#include <unistd.h>
#include "kerncompat.h"
#include "ctree.h"
#include "disk-io.h"
/*
* This is the C data type to use
*/
/* Change this from BITS_PER_LONG if there is something better... */
#if BITS_PER_LONG == 64
# define NBYTES(x) ((x) * 0x0101010101010101UL)
# define NSIZE 8
# define NSHIFT 3
typedef uint64_t unative_t;
#else
# define NBYTES(x) ((x) * 0x01010101U)
# define NSIZE 4
# define NSHIFT 2
typedef uint32_t unative_t;
#endif
/*
* These sub-operations are separate inlines since they can sometimes be
* specially optimized using architecture-specific hacks.
*/
/*
* The SHLBYTE() operation shifts each byte left by 1, *not*
* rolling over into the next byte
*/
static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
{
unative_t vv;
vv = (v << 1) & NBYTES(0xfe);
return vv;
}
/*
* The MASK() operation returns 0xFF in any byte for which the high
* bit is 1, 0x00 for any byte for which the high bit is 0.
*/
static inline __attribute_const__ unative_t MASK(unative_t v)
{
unative_t vv;
vv = v & NBYTES(0x80);
vv = (vv << 1) - (vv >> 7); /* Overflow on the top bit is OK */
return vv;
}
void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs)
{
uint8_t **dptr = (uint8_t **)ptrs;
uint8_t *p, *q;
int d, z, z0;
unative_t wd0, wq0, wp0, w10, w20;
z0 = disks - 3; /* Highest data disk */
p = dptr[z0+1]; /* XOR parity */
q = dptr[z0+2]; /* RS syndrome */
for ( d = 0 ; d < bytes ; d += NSIZE*1 ) {
wq0 = wp0 = *(unative_t *)&dptr[z0][d+0*NSIZE];
for ( z = z0-1 ; z >= 0 ; z-- ) {
wd0 = *(unative_t *)&dptr[z][d+0*NSIZE];
wp0 ^= wd0;
w20 = MASK(wq0);
w10 = SHLBYTE(wq0);
w20 &= NBYTES(0x1d);
w10 ^= w20;
wq0 = w10 ^ wd0;
}
*(unative_t *)&p[d+NSIZE*0] = wp0;
*(unative_t *)&q[d+NSIZE*0] = wq0;
}
}
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