xref: /openbmc/linux/arch/alpha/lib/csum_ipv6_magic.S (revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2) 
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
12	.globl csum_ipv6_magic
13	.align 4
14	.ent csum_ipv6_magic
15	.frame $30,0,$26,0
16csum_ipv6_magic:
17	.prologue 0
18
19	ldq	$0,0($16)	# e0    : load src & dst addr words
20	zapnot	$20,15,$20	# .. e1 : zero extend incoming csum
21	extqh	$18,1,$4	# e0    : byte swap len & proto while we wait
22	ldq	$1,8($16)	# .. e1 :
23
24	extbl	$18,1,$5	# e0	:
25	ldq	$2,0($17)	# .. e1 :
26	extbl	$18,2,$6	# e0 	:
27	ldq	$3,8($17)	# .. e1 :
28
29	extbl	$18,3,$18	# e0	:
30	sra	$4,32,$4	# e0	:
31	sll	$5,16,$5	# e0	:
32	addq	$20,$0,$20	# .. e1 : begin summing the words
33
34	sll	$6,8,$6		# e0	:
35	cmpult	$20,$0,$0	# .. e1 :
36	extwh	$19,7,$7	# e0    :
37	or	$4,$18,$18	# .. e1 :
38
39	extbl	$19,1,$19	# e0    :
40	or	$5,$6,$5	# .. e1 :
41	or	$18,$5,$18	# e0    : len complete
42	or	$19,$7,$19	# .. e1 :
43
44	sll	$19,48,$19	# e0    :
45	addq	$20,$1,$20	# .. e1 :
46	sra	$19,32,$19	# e0    : proto complete
47	cmpult	$20,$1,$1	# .. e1 :
48
49	nop			# e0    :
50	addq	$20,$2,$20	# .. e1 :
51	cmpult	$20,$2,$2	# e0    :
52	addq	$20,$3,$20	# .. e1 :
53
54	cmpult	$20,$3,$3	# e0    :
55	addq	$20,$18,$20	# .. e1 :
56	cmpult	$20,$18,$18	# e0    :
57	addq	$20,$19,$20	# .. e1 :
58
59	cmpult	$20,$19,$19	# e0    :
60	addq	$0,$1,$0	# .. e1 : merge the carries back into the csum
61	addq	$2,$3,$2	# e0    :
62	addq	$18,$19,$18	# .. e1 :
63
64	addq	$0,$2,$0	# e0    :
65	addq	$20,$18,$20	# .. e1 :
66	addq	$0,$20,$0	# e0    :
67	unop			#       :
68
69	extwl	$0,2,$2		# e0    : begin folding the 64-bit value
70	zapnot	$0,3,$3		# .. e1 :
71	extwl	$0,4,$1		# e0    :
72	addq	$2,$3,$3	# .. e1 :
73
74	extwl	$0,6,$0		# e0    :
75	addq	$3,$1,$3	# .. e1 :
76	addq	$0,$3,$0	# e0    :
77	unop			#       :
78
79	extwl	$0,2,$1		# e0    : fold 18-bit value
80	zapnot	$0,3,$0		# .. e1 :
81	addq	$0,$1,$0	# e0    :
82	unop			#       :
83
84	extwl	$0,2,$1		# e0    : fold 17-bit value
85	zapnot	$0,3,$0		# .. e1 :
86	addq	$0,$1,$0	# e0    :
87	not	$0,$0		# e1    : and complement.
88
89	zapnot	$0,3,$0		# e0    :
90	ret			# .. e1 :
91
92	.end csum_ipv6_magic
93