xref: /linux/arch/alpha/lib/csum_ipv6_magic.S (revision bcefe12eff5dca6fdfa94ed85e5bee66380d5cd9) 
1/*
2 * arch/alpha/lib/csum_ipv6_magic.S
3 * Contributed by Richard Henderson <rth@tamu.edu>
4 *
5 * unsigned short csum_ipv6_magic(struct in6_addr *saddr,
6 *                                struct in6_addr *daddr,
7 *                                __u32 len,
8 *                                unsigned short proto,
9 *                                unsigned int csum);
10 *
11 * Misalignment handling (which costs 16 instructions / 8 cycles)
12 * added by Ivan Kokshaysky <ink@jurassic.park.msu.ru>
13 */
14
15	.globl csum_ipv6_magic
16	.align 4
17	.ent csum_ipv6_magic
18	.frame $30,0,$26,0
19csum_ipv6_magic:
20	.prologue 0
21
22	ldq_u	$0,0($16)	# e0    : load src & dst addr words
23	zapnot	$20,15,$20	# .. e1 : zero extend incoming csum
24	extqh	$18,1,$4	# e0    : byte swap len & proto while we wait
25	ldq_u	$21,7($16)	# .. e1 : handle misalignment
26
27	extbl	$18,1,$5	# e0	:
28	ldq_u	$1,8($16)	# .. e1 :
29	extbl	$18,2,$6	# e0 	:
30	ldq_u	$22,15($16)	# .. e1 :
31
32	extbl	$18,3,$18	# e0	:
33	ldq_u	$2,0($17)	# .. e1 :
34	sra	$4,32,$4	# e0	:
35	ldq_u	$23,7($17)	# .. e1 :
36
37	extql	$0,$16,$0	# e0	:
38	ldq_u	$3,8($17)	# .. e1 :
39	extqh	$21,$16,$21	# e0	:
40	ldq_u	$24,15($17)	# .. e1 :
41
42	sll	$5,16,$5	# e0	:
43	or	$0,$21,$0	# .. e1 : 1st src word complete
44	extql	$1,$16,$1	# e0	:
45	addq	$20,$0,$20	# .. e1 : begin summing the words
46
47	extqh	$22,$16,$22	# e0	:
48	cmpult	$20,$0,$0	# .. e1 :
49	sll	$6,8,$6		# e0	:
50	or	$1,$22,$1	# .. e1 : 2nd src word complete
51
52	extql	$2,$17,$2	# e0	:
53	or	$4,$18,$18	# .. e1 :
54	extqh	$23,$17,$23	# e0	:
55	or	$5,$6,$5	# .. e1 :
56
57	extql	$3,$17,$3	# e0	:
58	or	$2,$23,$2	# .. e1 : 1st dst word complete
59	extqh	$24,$17,$24	# e0	:
60	or	$18,$5,$18	# .. e1 : len complete
61
62	extwh	$19,7,$7	# e0    :
63	or	$3,$24,$3	# .. e1 : 2nd dst word complete
64	extbl	$19,1,$19	# e0    :
65	addq	$20,$1,$20	# .. e1 :
66
67	or	$19,$7,$19	# e0    :
68	cmpult	$20,$1,$1	# .. e1 :
69	sll	$19,48,$19	# e0    :
70	nop			# .. e0 :
71
72	sra	$19,32,$19	# e0    : proto complete
73	addq	$20,$2,$20	# .. e1 :
74	cmpult	$20,$2,$2	# e0    :
75	addq	$20,$3,$20	# .. e1 :
76
77	cmpult	$20,$3,$3	# e0    :
78	addq	$20,$18,$20	# .. e1 :
79	cmpult	$20,$18,$18	# e0    :
80	addq	$20,$19,$20	# .. e1 :
81
82	cmpult	$20,$19,$19	# e0    :
83	addq	$0,$1,$0	# .. e1 : merge the carries back into the csum
84	addq	$2,$3,$2	# e0    :
85	addq	$18,$19,$18	# .. e1 :
86
87	addq	$0,$2,$0	# e0    :
88	addq	$20,$18,$20	# .. e1 :
89	addq	$0,$20,$0	# e0    :
90	unop			#       :
91
92	extwl	$0,2,$2		# e0    : begin folding the 64-bit value
93	zapnot	$0,3,$3		# .. e1 :
94	extwl	$0,4,$1		# e0    :
95	addq	$2,$3,$3	# .. e1 :
96
97	extwl	$0,6,$0		# e0    :
98	addq	$3,$1,$3	# .. e1 :
99	addq	$0,$3,$0	# e0    :
100	unop			#       :
101
102	extwl	$0,2,$1		# e0    : fold 18-bit value
103	zapnot	$0,3,$0		# .. e1 :
104	addq	$0,$1,$0	# e0    :
105	unop			#       :
106
107	extwl	$0,2,$1		# e0    : fold 17-bit value
108	zapnot	$0,3,$0		# .. e1 :
109	addq	$0,$1,$0	# e0    :
110	not	$0,$0		# .. e1 : and complement.
111
112	zapnot	$0,3,$0		# e0    :
113	ret			# .. e1 :
114
115	.end csum_ipv6_magic
116