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csum_ipv6_magic.S
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/*
* 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>
*/
#include <asm/export.h>
.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
EXPORT_SYMBOL(csum_ipv6_magic)