Root/drivers/md/raid6int.uc

1/* -*- linux-c -*- ------------------------------------------------------- *
2 *
3 * Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
4 *
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.
10 *
11 * ----------------------------------------------------------------------- */
12
13/*
14 * raid6int$#.c
15 *
16 * $#-way unrolled portable integer math RAID-6 instruction set
17 *
18 * This file is postprocessed using unroll.awk
19 */
20
21#include <linux/raid/pq.h>
22
23/*
24 * This is the C data type to use
25 */
26
27/* Change this from BITS_PER_LONG if there is something better... */
28#if BITS_PER_LONG == 64
29# define NBYTES(x) ((x) * 0x0101010101010101UL)
30# define NSIZE 8
31# define NSHIFT 3
32# define NSTRING "64"
33typedef u64 unative_t;
34#else
35# define NBYTES(x) ((x) * 0x01010101U)
36# define NSIZE 4
37# define NSHIFT 2
38# define NSTRING "32"
39typedef u32 unative_t;
40#endif
41
42
43
44/*
45 * IA-64 wants insane amounts of unrolling. On other architectures that
46 * is just a waste of space.
47 */
48#if ($# <= 8) || defined(__ia64__)
49
50
51/*
52 * These sub-operations are separate inlines since they can sometimes be
53 * specially optimized using architecture-specific hacks.
54 */
55
56/*
57 * The SHLBYTE() operation shifts each byte left by 1, *not*
58 * rolling over into the next byte
59 */
60static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
61{
62    unative_t vv;
63
64    vv = (v << 1) & NBYTES(0xfe);
65    return vv;
66}
67
68/*
69 * The MASK() operation returns 0xFF in any byte for which the high
70 * bit is 1, 0x00 for any byte for which the high bit is 0.
71 */
72static inline __attribute_const__ unative_t MASK(unative_t v)
73{
74    unative_t vv;
75
76    vv = v & NBYTES(0x80);
77    vv = (vv << 1) - (vv >> 7); /* Overflow on the top bit is OK */
78    return vv;
79}
80
81
82static void raid6_int$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
83{
84    u8 **dptr = (u8 **)ptrs;
85    u8 *p, *q;
86    int d, z, z0;
87
88    unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
89
90    z0 = disks - 3; /* Highest data disk */
91    p = dptr[z0+1]; /* XOR parity */
92    q = dptr[z0+2]; /* RS syndrome */
93
94    for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
95        wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];
96        for ( z = z0-1 ; z >= 0 ; z-- ) {
97            wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
98            wp$$ ^= wd$$;
99            w2$$ = MASK(wq$$);
100            w1$$ = SHLBYTE(wq$$);
101            w2$$ &= NBYTES(0x1d);
102            w1$$ ^= w2$$;
103            wq$$ = w1$$ ^ wd$$;
104        }
105        *(unative_t *)&p[d+NSIZE*$$] = wp$$;
106        *(unative_t *)&q[d+NSIZE*$$] = wq$$;
107    }
108}
109
110const struct raid6_calls raid6_intx$# = {
111    raid6_int$#_gen_syndrome,
112    NULL, /* always valid */
113    "int" NSTRING "x$#",
114    0
115};
116
117#endif
118

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