| /* -*- 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; |
| } |
| } |
| |