Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * arch/alpha/lib/csum_ipv6_magic.S
 * Contributed by Richard Henderson <rth@tamu.edu>
 *
 * unsigned short csum_ipv6_magic(struct in6_addr *saddr,
 *                                struct in6_addr *daddr,
 *                                __u32 len,
 *                                unsigned short proto,
 *                                unsigned int csum);
 *
 * Misalignment handling (which costs 16 instructions / 8 cycles)
 * added by Ivan Kokshaysky <ink@jurassic.park.msu.ru>
 */

        .globl csum_ipv6_magic
        .align 4
        .ent csum_ipv6_magic
        .frame $30,0,$26,0
csum_ipv6_magic:
        .prologue 0

        ldq_u   $0,0($16)       # e0    : load src & dst addr words
        zapnot  $20,15,$20      # .. e1 : zero extend incoming csum
        extqh   $18,1,$4        # e0    : byte swap len & proto while we wait
        ldq_u   $21,7($16)      # .. e1 : handle misalignment

        extbl   $18,1,$5        # e0    :
        ldq_u   $1,8($16)       # .. e1 :
        extbl   $18,2,$6        # e0    :
        ldq_u   $22,15($16)     # .. e1 :

        extbl   $18,3,$18       # e0    :
        ldq_u   $2,0($17)       # .. e1 :
        sra     $4,32,$4        # e0    :
        ldq_u   $23,7($17)      # .. e1 :

        extql   $0,$16,$0       # e0    :
        ldq_u   $3,8($17)       # .. e1 :
        extqh   $21,$16,$21     # e0    :
        ldq_u   $24,15($17)     # .. e1 :

        sll     $5,16,$5        # e0    :
        or      $0,$21,$0       # .. e1 : 1st src word complete
        extql   $1,$16,$1       # e0    :
        addq    $20,$0,$20      # .. e1 : begin summing the words

        extqh   $22,$16,$22     # e0    :
        cmpult  $20,$0,$0       # .. e1 :
        sll     $6,8,$6         # e0    :
        or      $1,$22,$1       # .. e1 : 2nd src word complete

        extql   $2,$17,$2       # e0    :
        or      $4,$18,$18      # .. e1 :
        extqh   $23,$17,$23     # e0    :
        or      $5,$6,$5        # .. e1 :

        extql   $3,$17,$3       # e0    :
        or      $2,$23,$2       # .. e1 : 1st dst word complete
        extqh   $24,$17,$24     # e0    :
        or      $18,$5,$18      # .. e1 : len complete

        extwh   $19,7,$7        # e0    :
        or      $3,$24,$3       # .. e1 : 2nd dst word complete
        extbl   $19,1,$19       # e0    :
        addq    $20,$1,$20      # .. e1 :

        or      $19,$7,$19      # e0    :
        cmpult  $20,$1,$1       # .. e1 :
        sll     $19,48,$19      # e0    :
        nop                     # .. e0 :

        sra     $19,32,$19      # e0    : proto complete
        addq    $20,$2,$20      # .. e1 :
        cmpult  $20,$2,$2       # e0    :
        addq    $20,$3,$20      # .. e1 :

        cmpult  $20,$3,$3       # e0    :
        addq    $20,$18,$20     # .. e1 :
        cmpult  $20,$18,$18     # e0    :
        addq    $20,$19,$20     # .. e1 :

        cmpult  $20,$19,$19     # e0    :
        addq    $0,$1,$0        # .. e1 : merge the carries back into the csum
        addq    $2,$3,$2        # e0    :
        addq    $18,$19,$18     # .. e1 :

        addq    $0,$2,$0        # e0    :
        addq    $20,$18,$20     # .. e1 :
        addq    $0,$20,$0       # e0    :
        unop                    #       :

        extwl   $0,2,$2         # e0    : begin folding the 64-bit value
        zapnot  $0,3,$3         # .. e1 :
        extwl   $0,4,$1         # e0    :
        addq    $2,$3,$3        # .. e1 :

        extwl   $0,6,$0         # e0    :
        addq    $3,$1,$3        # .. e1 :
        addq    $0,$3,$0        # e0    :
        unop                    #       :

        extwl   $0,2,$1         # e0    : fold 18-bit value
        zapnot  $0,3,$0         # .. e1 :
        addq    $0,$1,$0        # e0    :
        unop                    #       :

        extwl   $0,2,$1         # e0    : fold 17-bit value
        zapnot  $0,3,$0         # .. e1 :
        addq    $0,$1,$0        # e0    :
        not     $0,$0           # .. e1 : and complement.

        zapnot  $0,3,$0         # e0    :
        ret                     # .. e1 :

        .end csum_ipv6_magic