1 /* -*- linux-c -*- ------------------------------------------------------- *
3 * Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8 * Boston MA 02111-1307, USA; either version 2 of the License, or
9 * (at your option) any later version; incorporated herein by reference.
11 * ----------------------------------------------------------------------- */
16 * 1-way unrolled portable integer math RAID-6 instruction set
18 * This file was postprocessed using unroll.pl and then ported to userspace
23 * This is the C data type to use
26 /* Change this from BITS_PER_LONG if there is something better... */
27 #if BITS_PER_LONG == 64
28 # define NBYTES(x) ((x) * 0x0101010101010101UL)
31 typedef uint64_t unative_t;
33 # define NBYTES(x) ((x) * 0x01010101U)
36 typedef uint32_t unative_t;
40 * These sub-operations are separate inlines since they can sometimes be
41 * specially optimized using architecture-specific hacks.
45 * The SHLBYTE() operation shifts each byte left by 1, *not*
46 * rolling over into the next byte
48 static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
52 vv = (v << 1) & NBYTES(0xfe);
57 * The MASK() operation returns 0xFF in any byte for which the high
58 * bit is 1, 0x00 for any byte for which the high bit is 0.
60 static inline __attribute_const__ unative_t MASK(unative_t v)
64 vv = v & NBYTES(0x80);
65 vv = (vv << 1) - (vv >> 7); /* Overflow on the top bit is OK */
70 void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs)
72 uint8_t **dptr = (uint8_t **)ptrs;
76 unative_t wd0, wq0, wp0, w10, w20;
78 z0 = disks - 3; /* Highest data disk */
79 p = dptr[z0+1]; /* XOR parity */
80 q = dptr[z0+2]; /* RS syndrome */
82 for ( d = 0 ; d < bytes ; d += NSIZE*1 ) {
83 wq0 = wp0 = *(unative_t *)&dptr[z0][d+0*NSIZE];
84 for ( z = z0-1 ; z >= 0 ; z-- ) {
85 wd0 = *(unative_t *)&dptr[z][d+0*NSIZE];
93 *(unative_t *)&p[d+NSIZE*0] = wp0;
94 *(unative_t *)&q[d+NSIZE*0] = wq0;