summaryrefslogtreecommitdiff
path: root/arch/powerpc/lib/checksum.S
blob: 7874e8a80455c9620ab960ba1e15e5c8a6aece7b (plain)
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
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
/*
 * This file contains assembly-language implementations
 * of IP-style 1's complement checksum routines.
 *	
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
 */

#include <linux/sys.h>
#include <asm/processor.h>
#include <asm/errno.h>
#include <asm/ppc_asm.h>

	.text

/*
 * ip_fast_csum(buf, len) -- Optimized for IP header
 * len is in words and is always >= 5.
 */
_GLOBAL(ip_fast_csum)
	lwz	r0,0(r3)
	lwzu	r5,4(r3)
	addic.	r4,r4,-2
	addc	r0,r0,r5
	mtctr	r4
	blelr-
1:	lwzu	r4,4(r3)
	adde	r0,r0,r4
	bdnz	1b
	addze	r0,r0		/* add in final carry */
	rlwinm	r3,r0,16,0,31	/* fold two halves together */
	add	r3,r0,r3
	not	r3,r3
	srwi	r3,r3,16
	blr

/*
 * Compute checksum of TCP or UDP pseudo-header:
 *   csum_tcpudp_magic(saddr, daddr, len, proto, sum)
 */	
_GLOBAL(csum_tcpudp_magic)
	rlwimi	r5,r6,16,0,15	/* put proto in upper half of len */
	addc	r0,r3,r4	/* add 4 32-bit words together */
	adde	r0,r0,r5
	adde	r0,r0,r7
	addze	r0,r0		/* add in final carry */
	rlwinm	r3,r0,16,0,31	/* fold two halves together */
	add	r3,r0,r3
	not	r3,r3
	srwi	r3,r3,16
	blr

/*
 * computes the checksum of a memory block at buff, length len,
 * and adds in "sum" (32-bit)
 *
 * csum_partial(buff, len, sum)
 */
_GLOBAL(csum_partial)
	addic	r0,r5,0
	subi	r3,r3,4
	srwi.	r6,r4,2
	beq	3f		/* if we're doing < 4 bytes */
	andi.	r5,r3,2		/* Align buffer to longword boundary */
	beq+	1f
	lhz	r5,4(r3)	/* do 2 bytes to get aligned */
	addi	r3,r3,2
	subi	r4,r4,2
	addc	r0,r0,r5
	srwi.	r6,r4,2		/* # words to do */
	beq	3f
1:	mtctr	r6
2:	lwzu	r5,4(r3)	/* the bdnz has zero overhead, so it should */
	adde	r0,r0,r5	/* be unnecessary to unroll this loop */
	bdnz	2b
	andi.	r4,r4,3
3:	cmpwi	0,r4,2
	blt+	4f
	lhz	r5,4(r3)
	addi	r3,r3,2
	subi	r4,r4,2
	adde	r0,r0,r5
4:	cmpwi	0,r4,1
	bne+	5f
	lbz	r5,4(r3)
	slwi	r5,r5,8		/* Upper byte of word */
	adde	r0,r0,r5
5:	addze	r3,r0		/* add in final carry */
	blr

/*
 * Computes the checksum of a memory block at src, length len,
 * and adds in "sum" (32-bit), while copying the block to dst.
 * If an access exception occurs on src or dst, it stores -EFAULT
 * to *src_err or *dst_err respectively, and (for an error on
 * src) zeroes the rest of dst.
 *
 * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
 */
_GLOBAL(csum_partial_copy_generic)
	addic	r0,r6,0
	subi	r3,r3,4
	subi	r4,r4,4
	srwi.	r6,r5,2
	beq	3f		/* if we're doing < 4 bytes */
	andi.	r9,r4,2		/* Align dst to longword boundary */
	beq+	1f
81:	lhz	r6,4(r3)	/* do 2 bytes to get aligned */
	addi	r3,r3,2
	subi	r5,r5,2
91:	sth	r6,4(r4)
	addi	r4,r4,2
	addc	r0,r0,r6
	srwi.	r6,r5,2		/* # words to do */
	beq	3f
1:	srwi.	r6,r5,4		/* # groups of 4 words to do */
	beq	10f
	mtctr	r6
71:	lwz	r6,4(r3)
72:	lwz	r9,8(r3)
73:	lwz	r10,12(r3)
74:	lwzu	r11,16(r3)
	adde	r0,r0,r6
75:	stw	r6,4(r4)
	adde	r0,r0,r9
76:	stw	r9,8(r4)
	adde	r0,r0,r10
77:	stw	r10,12(r4)
	adde	r0,r0,r11
78:	stwu	r11,16(r4)
	bdnz	71b
10:	rlwinm.	r6,r5,30,30,31	/* # words left to do */
	beq	13f
	mtctr	r6
82:	lwzu	r9,4(r3)
92:	stwu	r9,4(r4)
	adde	r0,r0,r9
	bdnz	82b
13:	andi.	r5,r5,3
3:	cmpwi	0,r5,2
	blt+	4f
83:	lhz	r6,4(r3)
	addi	r3,r3,2
	subi	r5,r5,2
93:	sth	r6,4(r4)
	addi	r4,r4,2
	adde	r0,r0,r6
4:	cmpwi	0,r5,1
	bne+	5f
84:	lbz	r6,4(r3)
94:	stb	r6,4(r4)
	slwi	r6,r6,8		/* Upper byte of word */
	adde	r0,r0,r6
5:	addze	r3,r0		/* add in final carry */
	blr

/* These shouldn't go in the fixup section, since that would
   cause the ex_table addresses to get out of order. */

src_error_4:
	mfctr	r6		/* update # bytes remaining from ctr */
	rlwimi	r5,r6,4,0,27
	b	79f
src_error_1:
	li	r6,0
	subi	r5,r5,2
95:	sth	r6,4(r4)
	addi	r4,r4,2
79:	srwi.	r6,r5,2
	beq	3f
	mtctr	r6
src_error_2:
	li	r6,0
96:	stwu	r6,4(r4)
	bdnz	96b
3:	andi.	r5,r5,3
	beq	src_error
src_error_3:
	li	r6,0
	mtctr	r5
	addi	r4,r4,3
97:	stbu	r6,1(r4)
	bdnz	97b
src_error:
	cmpwi	0,r7,0
	beq	1f
	li	r6,-EFAULT
	stw	r6,0(r7)
1:	addze	r3,r0
	blr

dst_error:
	cmpwi	0,r8,0
	beq	1f
	li	r6,-EFAULT
	stw	r6,0(r8)
1:	addze	r3,r0
	blr

.section __ex_table,"a"
	.long	81b,src_error_1
	.long	91b,dst_error
	.long	71b,src_error_4
	.long	72b,src_error_4
	.long	73b,src_error_4
	.long	74b,src_error_4
	.long	75b,dst_error
	.long	76b,dst_error
	.long	77b,dst_error
	.long	78b,dst_error
	.long	82b,src_error_2
	.long	92b,dst_error
	.long	83b,src_error_3
	.long	93b,dst_error
	.long	84b,src_error_3
	.long	94b,dst_error
	.long	95b,dst_error
	.long	96b,dst_error
	.long	97b,dst_error