xref: /openbmc/linux/arch/alpha/lib/csum_ipv6_magic.S (revision fb574682) 
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
21csum_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