1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
/*
* Optmized version of the ip_fast_csum() function
* Used for calculating IP header checksum
*
* Return: 16bit checksum, complemented
*
* Inputs:
* in0: address of buffer to checksum (char *)
* in1: length of the buffer (int)
*
* Copyright (C) 2002, 2006 Intel Corp.
* Copyright (C) 2002, 2006 Ken Chen <kenneth.w.chen@intel.com>
*/
#include <asm/asmmacro.h>
/*
* Since we know that most likely this function is called with buf aligned
* on 4-byte boundary and 20 bytes in length, we can execution rather quickly
* versus calling generic version of do_csum, which has lots of overhead in
* handling various alignments and sizes. However, due to lack of constrains
* put on the function input argument, cases with alignment not on 4-byte or
* size not equal to 20 bytes will be handled by the generic do_csum function.
*/
#define in0 r32
#define in1 r33
#define in2 r34
#define in3 r35
#define in4 r36
#define ret0 r8
GLOBAL_ENTRY(ip_fast_csum)
.prologue
.body
cmp.ne p6,p7=5,in1 // size other than 20 byte?
and r14=3,in0 // is it aligned on 4-byte?
add r15=4,in0 // second source pointer
;;
cmp.ne.or.andcm p6,p7=r14,r0
;;
(p7) ld4 r20=[in0],8
(p7) ld4 r21=[r15],8
(p6) br.spnt .generic
;;
ld4 r22=[in0],8
ld4 r23=[r15],8
;;
ld4 r24=[in0]
add r20=r20,r21
add r22=r22,r23
;;
add r20=r20,r22
;;
add r20=r20,r24
;;
shr.u ret0=r20,16 // now need to add the carry
zxt2 r20=r20
;;
add r20=ret0,r20
;;
shr.u ret0=r20,16 // add carry again
zxt2 r20=r20
;;
add r20=ret0,r20
;;
shr.u ret0=r20,16
zxt2 r20=r20
;;
add r20=ret0,r20
mov r9=0xffff
;;
andcm ret0=r9,r20
.restore sp // reset frame state
br.ret.sptk.many b0
;;
.generic:
.prologue
.save ar.pfs, r35
alloc r35=ar.pfs,2,2,2,0
.save rp, r34
mov r34=b0
.body
dep.z out1=in1,2,30
mov out0=in0
;;
br.call.sptk.many b0=do_csum
;;
andcm ret0=-1,ret0
mov ar.pfs=r35
mov b0=r34
br.ret.sptk.many b0
END(ip_fast_csum)
GLOBAL_ENTRY(csum_ipv6_magic)
ld4 r20=[in0],4
ld4 r21=[in1],4
dep r15=in3,in2,32,16
;;
ld4 r22=[in0],4
ld4 r23=[in1],4
mux1 r15=r15,@rev
;;
ld4 r24=[in0],4
ld4 r25=[in1],4
shr.u r15=r15,16
add r16=r20,r21
add r17=r22,r23
;;
ld4 r26=[in0],4
ld4 r27=[in1],4
add r18=r24,r25
add r8=r16,r17
;;
add r19=r26,r27
add r8=r8,r18
;;
add r8=r8,r19
add r15=r15,in4
;;
add r8=r8,r15
;;
shr.u r10=r8,32 // now fold sum into short
zxt4 r11=r8
;;
add r8=r10,r11
;;
shr.u r10=r8,16 // yeah, keep it rolling
zxt2 r11=r8
;;
add r8=r10,r11
;;
shr.u r10=r8,16 // three times lucky
zxt2 r11=r8
;;
add r8=r10,r11
mov r9=0xffff
;;
andcm r8=r9,r8
br.ret.sptk.many b0
END(csum_ipv6_magic)
|
