linux/lib/raid6/int.uc
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   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 * int$#.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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