LXR linux/arch/alpha/lib/csum_ipv6

   1/*
   2 * arch/alpha/lib/csum_ipv6_magic.S
   3 * Contributed by Richard Henderson <rth@tamu.edu>
   4 *
   5 * unsigned short csum_ipv6_magic(struct in6_addr *saddr,
   6 *                                struct in6_addr *daddr,
   7 *                                __u32 len,
   8 *                                unsigned short proto,
   9 *                                unsigned int csum);
  10 *
  11 * Misalignment handling (which costs 16 instructions / 8 cycles)
  12 * added by Ivan Kokshaysky <ink@jurassic.park.msu.ru>
  13 */
  14
  15        .globl csum_ipv6_magic
  16        .align 4
  17        .ent csum_ipv6_magic
  18        .frame $30,0,$26,0
  19csum_ipv6_magic:
  20        .prologue 0
  21
  22        ldq_u   $0,0($16)       # e0    : load src & dst addr words
  23        zapnot  $20,15,$20      # .. e1 : zero extend incoming csum
  24        extqh   $18,1,$4        # e0    : byte swap len & proto while we wait
  25        ldq_u   $21,7($16)      # .. e1 : handle misalignment
  26
  27        extbl   $18,1,$5        # e0    :
  28        ldq_u   $1,8($16)       # .. e1 :
  29        extbl   $18,2,$6        # e0    :
  30        ldq_u   $22,15($16)     # .. e1 :
  31
  32        extbl   $18,3,$18       # e0    :
  33        ldq_u   $2,0($17)       # .. e1 :
  34        sra     $4,32,$4        # e0    :
  35        ldq_u   $23,7($17)      # .. e1 :
  36
  37        extql   $0,$16,$0       # e0    :
  38        ldq_u   $3,8($17)       # .. e1 :
  39        extqh   $21,$16,$21     # e0    :
  40        ldq_u   $24,15($17)     # .. e1 :
  41
  42        sll     $5,16,$5        # e0    :
  43        or      $0,$21,$0       # .. e1 : 1st src word complete
  44        extql   $1,$16,$1       # e0    :
  45        addq    $20,$0,$20      # .. e1 : begin summing the words
  46
  47        extqh   $22,$16,$22     # e0    :
  48        cmpult  $20,$0,$0       # .. e1 :
  49        sll     $6,8,$6         # e0    :
  50        or      $1,$22,$1       # .. e1 : 2nd src word complete
  51
  52        extql   $2,$17,$2       # e0    :
  53        or      $4,$18,$18      # .. e1 :
  54        extqh   $23,$17,$23     # e0    :
  55        or      $5,$6,$5        # .. e1 :
  56
  57        extql   $3,$17,$3       # e0    :
  58        or      $2,$23,$2       # .. e1 : 1st dst word complete
  59        extqh   $24,$17,$24     # e0    :
  60        or      $18,$5,$18      # .. e1 : len complete
  61
  62        extwh   $19,7,$7        # e0    :
  63        or      $3,$24,$3       # .. e1 : 2nd dst word complete
  64        extbl   $19,1,$19       # e0    :
  65        addq    $20,$1,$20      # .. e1 :
  66
  67        or      $19,$7,$19      # e0    :
  68        cmpult  $20,$1,$1       # .. e1 :
  69        sll     $19,48,$19      # e0    :
  70        nop                     # .. e0 :
  71
  72        sra     $19,32,$19      # e0    : proto complete
  73        addq    $20,$2,$20      # .. e1 :
  74        cmpult  $20,$2,$2       # e0    :
  75        addq    $20,$3,$20      # .. e1 :
  76
  77        cmpult  $20,$3,$3       # e0    :
  78        addq    $20,$18,$20     # .. e1 :
  79        cmpult  $20,$18,$18     # e0    :
  80        addq    $20,$19,$20     # .. e1 :
  81
  82        cmpult  $20,$19,$19     # e0    :
  83        addq    $0,$1,$0        # .. e1 : merge the carries back into the csum
  84        addq    $2,$3,$2        # e0    :
  85        addq    $18,$19,$18     # .. e1 :
  86
  87        addq    $0,$2,$0        # e0    :
  88        addq    $20,$18,$20     # .. e1 :
  89        addq    $0,$20,$0       # e0    :
  90        unop                    #       :
  91
  92        extwl   $0,2,$2         # e0    : begin folding the 64-bit value
  93        zapnot  $0,3,$3         # .. e1 :
  94        extwl   $0,4,$1         # e0    :
  95        addq    $2,$3,$3        # .. e1 :
  96
  97        extwl   $0,6,$0         # e0    :
  98        addq    $3,$1,$3        # .. e1 :
  99        addq    $0,$3,$0        # e0    :
 100        unop                    #       :
 101
 102        extwl   $0,2,$1         # e0    : fold 18-bit value
 103        zapnot  $0,3,$0         # .. e1 :
 104        addq    $0,$1,$0        # e0    :
 105        unop                    #       :
 106
 107        extwl   $0,2,$1         # e0    : fold 17-bit value
 108        zapnot  $0,3,$0         # .. e1 :
 109        addq    $0,$1,$0        # e0    :
 110        not     $0,$0           # .. e1 : and complement.
 111
 112        zapnot  $0,3,$0         # e0    :
 113        ret                     # .. e1 :
 114
 115        .end csum_ipv6_magic
 116