arch/alpha/lib/csum_ipv6_magic.S

   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
  12         .globl csum_ipv6_magic
  13         .align 4
  14         .ent csum_ipv6_magic
  15         .frame $30,0,$26,0
  16 csum_ipv6_magic:
  17         .prologue 0
  18
  19         ldq     $0,0($16)       # e0    : load src & dst addr words
  20         zapnot  $20,15,$20      # .. e1 : zero extend incoming csum
  21         extqh   $18,1,$4        # e0    : byte swap len & proto while we wait
  22         ldq     $1,8($16)       # .. e1 :
  23
  24         extbl   $18,1,$5        # e0    :
  25         ldq     $2,0($17)       # .. e1 :
  26         extbl   $18,2,$6        # e0    :
  27         ldq     $3,8($17)       # .. e1 :
  28
  29         extbl   $18,3,$18       # e0    :
  30         sra     $4,32,$4        # e0    :
  31         sll     $5,16,$5        # e0    :
  32         addq    $20,$0,$20      # .. e1 : begin summing the words
  33
  34         sll     $6,8,$6         # e0    :
  35         cmpult  $20,$0,$0       # .. e1 :
  36         extwh   $19,7,$7        # e0    :
  37         or      $4,$18,$18      # .. e1 :
  38
  39         extbl   $19,1,$19       # e0    :
  40         or      $5,$6,$5        # .. e1 :
  41         or      $18,$5,$18      # e0    : len complete
  42         or      $19,$7,$19      # .. e1 :
  43
  44         sll     $19,48,$19      # e0    :
  45         addq    $20,$1,$20      # .. e1 :
  46         sra     $19,32,$19      # e0    : proto complete
  47         cmpult  $20,$1,$1       # .. e1 :
  48
  49         nop                     # e0    :
  50         addq    $20,$2,$20      # .. e1 :
  51         cmpult  $20,$2,$2       # e0    :
  52         addq    $20,$3,$20      # .. e1 :
  53
  54         cmpult  $20,$3,$3       # e0    :
  55         addq    $20,$18,$20     # .. e1 :
  56         cmpult  $20,$18,$18     # e0    :
  57         addq    $20,$19,$20     # .. e1 :
  58
  59         cmpult  $20,$19,$19     # e0    :
  60         addq    $0,$1,$0        # .. e1 : merge the carries back into the csum
  61         addq    $2,$3,$2        # e0    :
  62         addq    $18,$19,$18     # .. e1 :
  63
  64         addq    $0,$2,$0        # e0    :
  65         addq    $20,$18,$20     # .. e1 :
  66         addq    $0,$20,$0       # e0    :
  67         unop                    #       :
  68
  69         extwl   $0,2,$2         # e0    : begin folding the 64-bit value
  70         zapnot  $0,3,$3         # .. e1 :
  71         extwl   $0,4,$1         # e0    :
  72         addq    $2,$3,$3        # .. e1 :
  73
  74         extwl   $0,6,$0         # e0    :
  75         addq    $3,$1,$3        # .. e1 :
  76         addq    $0,$3,$0        # e0    :
  77         unop                    #       :
  78
  79         extwl   $0,2,$1         # e0    : fold 18-bit value
  80         zapnot  $0,3,$0         # .. e1 :
  81         addq    $0,$1,$0        # e0    :
  82         unop                    #       :
  83
  84         extwl   $0,2,$1         # e0    : fold 17-bit value
  85         zapnot  $0,3,$0         # .. e1 :
  86         addq    $0,$1,$0        # e0    :
  87         not     $0,$0           # e1    : and complement.
  88
  89         zapnot  $0,3,$0         # e0    :
  90         ret                     # .. e1 :
  91
  92         .end csum_ipv6_magic