lib/raid6/int.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  * int$#.c
  15  *
  16  * $#-way unrolled portable integer math RAID-6 instruction set
  17  *
  18  * This file is postprocessed using unroll.awk
  19  */
  20
  21 #include <linux/raid/pq.h>
  22
  23 /*
  24  * This is the C data type to use
  25  */
  26
  27 /* Change this from BITS_PER_LONG if there is something better... */
  28 #if BITS_PER_LONG == 64
  29 # define NBYTES(x) ((x) * 0x0101010101010101UL)
  30 # define NSIZE  8
  31 # define NSHIFT 3
  32 # define NSTRING "64"
  33 typedef u64 unative_t;
  34 #else
  35 # define NBYTES(x) ((x) * 0x01010101U)
  36 # define NSIZE  4
  37 # define NSHIFT 2
  38 # define NSTRING "32"
  39 typedef u32 unative_t;
  40 #endif
  41
  42
  43
  44 /*
  45  * IA-64 wants insane amounts of unrolling.  On other architectures that
  46  * is just a waste of space.
  47  */
  48 #if ($# <= 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  */
  60 static 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  */
  72 static 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
  82 static 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
 110 static void raid6_int$#_xor_syndrome(int disks, int start, int stop,
 111                                      size_t bytes, void **ptrs)
 112 {
 113         u8 **dptr = (u8 **)ptrs;
 114         u8 *p, *q;
 115         int d, z, z0;
 116
 117         unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
 118
 119         z0 = stop;              /* P/Q right side optimization */
 120         p = dptr[disks-2];      /* XOR parity */
 121         q = dptr[disks-1];      /* RS syndrome */
 122
 123         for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
 124                 /* P/Q data pages */
 125                 wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];
 126                 for ( z = z0-1 ; z >= start ; z-- ) {
 127                         wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];
 128                         wp$$ ^= wd$$;
 129                         w2$$ = MASK(wq$$);
 130                         w1$$ = SHLBYTE(wq$$);
 131                         w2$$ &= NBYTES(0x1d);
 132                         w1$$ ^= w2$$;
 133                         wq$$ = w1$$ ^ wd$$;
 134                 }
 135                 /* P/Q left side optimization */
 136                 for ( z = start-1 ; z >= 0 ; z-- ) {
 137                         w2$$ = MASK(wq$$);
 138                         w1$$ = SHLBYTE(wq$$);
 139                         w2$$ &= NBYTES(0x1d);
 140                         wq$$ = w1$$ ^ w2$$;
 141                 }
 142                 *(unative_t *)&p[d+NSIZE*$$] ^= wp$$;
 143                 *(unative_t *)&q[d+NSIZE*$$] ^= wq$$;
 144         }
 145
 146 }
 147
 148 const struct raid6_calls raid6_intx$# = {
 149         raid6_int$#_gen_syndrome,
 150         raid6_int$#_xor_syndrome,
 151         NULL,                   /* always valid */
 152         "int" NSTRING "x$#",
 153         0
 154 };
 155
 156 #endif