LXR linux/arch/alpha/lib/csum_ipv6

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * arch/alpha/lib/csum_ipv6_magic.S
   4 * Contributed by Richard Henderson <rth@tamu.edu>
   5 *
   6 * unsigned short csum_ipv6_magic(struct in6_addr *saddr,
   7 *                                struct in6_addr *daddr,
   8 *                                __u32 len,
   9 *                                unsigned short proto,
  10 *                                unsigned int csum);
  11 *
  12 * Misalignment handling (which costs 16 instructions / 8 cycles)
  13 * added by Ivan Kokshaysky <ink@jurassic.park.msu.ru>
  14 */
  15
  16#include <asm/export.h>
  17        .globl csum_ipv6_magic
  18        .align 4
  19        .ent csum_ipv6_magic
  20        .frame $30,0,$26,0
  21csum_ipv6_magic:
  22        .prologue 0
  23
  24        ldq_u   $0,0($16)       # e0    : load src & dst addr words
  25        zapnot  $20,15,$20      # .. e1 : zero extend incoming csum
  26        extqh   $18,1,$4        # e0    : byte swap len & proto while we wait
  27        ldq_u   $21,7($16)      # .. e1 : handle misalignment
  28
  29        extbl   $18,1,$5        # e0    :
  30        ldq_u   $1,8($16)       # .. e1 :
  31        extbl   $18,2,$6        # e0    :
  32        ldq_u   $22,15($16)     # .. e1 :
  33
  34        extbl   $18,3,$18       # e0    :
  35        ldq_u   $2,0($17)       # .. e1 :
  36        sra     $4,32,$4        # e0    :
  37        ldq_u   $23,7($17)      # .. e1 :
  38
  39        extql   $0,$16,$0       # e0    :
  40        ldq_u   $3,8($17)       # .. e1 :
  41        extqh   $21,$16,$21     # e0    :
  42        ldq_u   $24,15($17)     # .. e1 :
  43
  44        sll     $5,16,$5        # e0    :
  45        or      $0,$21,$0       # .. e1 : 1st src word complete
  46        extql   $1,$16,$1       # e0    :
  47        addq    $20,$0,$20      # .. e1 : begin summing the words
  48
  49        extqh   $22,$16,$22     # e0    :
  50        cmpult  $20,$0,$0       # .. e1 :
  51        sll     $6,8,$6         # e0    :
  52        or      $1,$22,$1       # .. e1 : 2nd src word complete
  53
  54        extql   $2,$17,$2       # e0    :
  55        or      $4,$18,$18      # .. e1 :
  56        extqh   $23,$17,$23     # e0    :
  57        or      $5,$6,$5        # .. e1 :
  58
  59        extql   $3,$17,$3       # e0    :
  60        or      $2,$23,$2       # .. e1 : 1st dst word complete
  61        extqh   $24,$17,$24     # e0    :
  62        or      $18,$5,$18      # .. e1 : len complete
  63
  64        extwh   $19,7,$7        # e0    :
  65        or      $3,$24,$3       # .. e1 : 2nd dst word complete
  66        extbl   $19,1,$19       # e0    :
  67        addq    $20,$1,$20      # .. e1 :
  68
  69        or      $19,$7,$19      # e0    :
  70        cmpult  $20,$1,$1       # .. e1 :
  71        sll     $19,48,$19      # e0    :
  72        nop                     # .. e0 :
  73
  74        sra     $19,32,$19      # e0    : proto complete
  75        addq    $20,$2,$20      # .. e1 :
  76        cmpult  $20,$2,$2       # e0    :
  77        addq    $20,$3,$20      # .. e1 :
  78
  79        cmpult  $20,$3,$3       # e0    :
  80        addq    $20,$18,$20     # .. e1 :
  81        cmpult  $20,$18,$18     # e0    :
  82        addq    $20,$19,$20     # .. e1 :
  83
  84        cmpult  $20,$19,$19     # e0    :
  85        addq    $0,$1,$0        # .. e1 : merge the carries back into the csum
  86        addq    $2,$3,$2        # e0    :
  87        addq    $18,$19,$18     # .. e1 :
  88
  89        addq    $0,$2,$0        # e0    :
  90        addq    $20,$18,$20     # .. e1 :
  91        addq    $0,$20,$0       # e0    :
  92        unop                    #       :
  93
  94        extwl   $0,2,$2         # e0    : begin folding the 64-bit value
  95        zapnot  $0,3,$3         # .. e1 :
  96        extwl   $0,4,$1         # e0    :
  97        addq    $2,$3,$3        # .. e1 :
  98
  99        extwl   $0,6,$0         # e0    :
 100        addq    $3,$1,$3        # .. e1 :
 101        addq    $0,$3,$0        # e0    :
 102        unop                    #       :
 103
 104        extwl   $0,2,$1         # e0    : fold 18-bit value
 105        zapnot  $0,3,$0         # .. e1 :
 106        addq    $0,$1,$0        # e0    :
 107        unop                    #       :
 108
 109        extwl   $0,2,$1         # e0    : fold 17-bit value
 110        zapnot  $0,3,$0         # .. e1 :
 111        addq    $0,$1,$0        # e0    :
 112        not     $0,$0           # .. e1 : and complement.
 113
 114        zapnot  $0,3,$0         # e0    :
 115        ret                     # .. e1 :
 116
 117        .end csum_ipv6_magic
 118        EXPORT_SYMBOL(csum_ipv6_magic)
 119