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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/alpha/lib/csum_ipv6_magic.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/*

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 * arch/alpha/lib/csum_ipv6_magic.S

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 * Contributed by Richard Henderson <[email protected]>

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 *

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 * unsigned short csum_ipv6_magic(struct in6_addr *saddr,

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 *                                struct in6_addr *daddr,

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 *                                __u32 len,

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 *                                unsigned short proto,

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 *                                unsigned int csum);

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 *

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 * Misalignment handling (which costs 16 instructions / 8 cycles)

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 * added by Ivan Kokshaysky <[email protected]>

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 */

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#include <linux/export.h>

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	.globl csum_ipv6_magic

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	.align 4

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	.ent csum_ipv6_magic

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	.frame $30,0,$26,0

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csum_ipv6_magic:

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	.prologue 0

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	ldq_u	$0,0($16)	# e0    : load src & dst addr words

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	zapnot	$20,15,$20	# .. e1 : zero extend incoming csum

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	extqh	$18,1,$4	# e0    : byte swap len & proto while we wait

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	ldq_u	$21,7($16)	# .. e1 : handle misalignment

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	extbl	$18,1,$5	# e0	:

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	ldq_u	$1,8($16)	# .. e1 :

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	extbl	$18,2,$6	# e0 	:

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	ldq_u	$22,15($16)	# .. e1 :

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	extbl	$18,3,$18	# e0	:

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	ldq_u	$2,0($17)	# .. e1 :

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	sra	$4,32,$4	# e0	:

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	ldq_u	$23,7($17)	# .. e1 :

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	extql	$0,$16,$0	# e0	:

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	ldq_u	$3,8($17)	# .. e1 :

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	extqh	$21,$16,$21	# e0	:

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	ldq_u	$24,15($17)	# .. e1 :

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	sll	$5,16,$5	# e0	:

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	or	$0,$21,$0	# .. e1 : 1st src word complete

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	extql	$1,$16,$1	# e0	:

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	addq	$20,$0,$20	# .. e1 : begin summing the words

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	extqh	$22,$16,$22	# e0	:

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	cmpult	$20,$0,$0	# .. e1 :

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	sll	$6,8,$6		# e0	:

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	or	$1,$22,$1	# .. e1 : 2nd src word complete

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	extql	$2,$17,$2	# e0	:

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	or	$4,$18,$18	# .. e1 :

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	extqh	$23,$17,$23	# e0	:

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	or	$5,$6,$5	# .. e1 :

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	extql	$3,$17,$3	# e0	:

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	or	$2,$23,$2	# .. e1 : 1st dst word complete

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	extqh	$24,$17,$24	# e0	:

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	or	$18,$5,$18	# .. e1 : len complete

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	extwh	$19,7,$7	# e0    :

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	or	$3,$24,$3	# .. e1 : 2nd dst word complete

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	extbl	$19,1,$19	# e0    :

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	addq	$20,$1,$20	# .. e1 :

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	or	$19,$7,$19	# e0    :

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	cmpult	$20,$1,$1	# .. e1 :

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	sll	$19,48,$19	# e0    :

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	nop			# .. e0 :

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	sra	$19,32,$19	# e0    : proto complete

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	addq	$20,$2,$20	# .. e1 :

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	cmpult	$20,$2,$2	# e0    :

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	addq	$20,$3,$20	# .. e1 :

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	cmpult	$20,$3,$3	# e0    :

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	addq	$20,$18,$20	# .. e1 :

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	cmpult	$20,$18,$18	# e0    :

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	addq	$20,$19,$20	# .. e1 :

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	cmpult	$20,$19,$19	# e0    :

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	addq	$0,$1,$0	# .. e1 : merge the carries back into the csum

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	addq	$2,$3,$2	# e0    :

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	addq	$18,$19,$18	# .. e1 :

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	addq	$0,$2,$0	# e0    :

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	addq	$20,$18,$20	# .. e1 :

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	addq	$0,$20,$0	# e0    :

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	unop			#       :

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	extwl	$0,2,$2		# e0    : begin folding the 64-bit value

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

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	extwl	$0,4,$1		# e0    :

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	addq	$2,$3,$3	# .. e1 :

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	extwl	$0,6,$0		# e0    :

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	addq	$3,$1,$3	# .. e1 :

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	addq	$0,$3,$0	# e0    :

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	unop			#       :

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	extwl	$0,2,$1		# e0    : fold 18-bit value

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

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	addq	$0,$1,$0	# e0    :

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	unop			#       :

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	extwl	$0,2,$1		# e0    : fold 17-bit value

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

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	addq	$0,$1,$0	# e0    :

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	not	$0,$0		# .. e1 : and complement.

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	zapnot	$0,3,$0		# e0    :

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	ret			# .. e1 :

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	.end csum_ipv6_magic

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	EXPORT_SYMBOL(csum_ipv6_magic)

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