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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
21 csum_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