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1 | /* |
2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. |
3 | * |
4 | * This program is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU General Public License |
6 | * as published by the Free Software Foundation, version 2. |
7 | * |
8 | * This program is distributed in the hope that it will be useful, but |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
11 | * NON INFRINGEMENT. See the GNU General Public License for |
12 | * more details. |
13 | * Support code for the main lib/checksum.c. |
14 | */ |
15 | |
16 | #include <net/checksum.h> |
17 | #include <linux/module.h> |
18 | |
19 | __wsum do_csum(const unsigned char *buff, int len) |
20 | { |
21 | int odd, count; |
22 | unsigned long result = 0; |
23 | |
24 | if (len <= 0) |
25 | goto out; |
26 | odd = 1 & (unsigned long) buff; |
27 | if (odd) { |
28 | result = (*buff << 8); |
29 | len--; |
30 | buff++; |
31 | } |
32 | count = len >> 1; /* nr of 16-bit words.. */ |
33 | if (count) { |
34 | if (2 & (unsigned long) buff) { |
35 | result += *(const unsigned short *)buff; |
36 | count--; |
37 | len -= 2; |
38 | buff += 2; |
39 | } |
40 | count >>= 1; /* nr of 32-bit words.. */ |
41 | if (count) { |
42 | #ifdef __tilegx__ |
43 | if (4 & (unsigned long) buff) { |
44 | unsigned int w = *(const unsigned int *)buff; |
45 | result = __insn_v2sadau(result, w, 0); |
46 | count--; |
47 | len -= 4; |
48 | buff += 4; |
49 | } |
50 | count >>= 1; /* nr of 64-bit words.. */ |
51 | #endif |
52 | |
53 | /* |
54 | * This algorithm could wrap around for very |
55 | * large buffers, but those should be impossible. |
56 | */ |
57 | BUG_ON(count >= 65530); |
58 | |
59 | while (count) { |
60 | unsigned long w = *(const unsigned long *)buff; |
61 | count--; |
62 | buff += sizeof(w); |
63 | #ifdef __tilegx__ |
64 | result = __insn_v2sadau(result, w, 0); |
65 | #else |
66 | result = __insn_sadah_u(result, w, 0); |
67 | #endif |
68 | } |
69 | #ifdef __tilegx__ |
70 | if (len & 4) { |
71 | unsigned int w = *(const unsigned int *)buff; |
72 | result = __insn_v2sadau(result, w, 0); |
73 | buff += 4; |
74 | } |
75 | #endif |
76 | } |
77 | if (len & 2) { |
78 | result += *(const unsigned short *) buff; |
79 | buff += 2; |
80 | } |
81 | } |
82 | if (len & 1) |
83 | result += *buff; |
84 | result = csum_long(result); |
85 | if (odd) |
86 | result = swab16(result); |
87 | out: |
88 | return result; |
89 | } |
90 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9