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-rw-r--r--arch/powerpc/lib/checksum.S225
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1/*
2 * This file contains assembly-language implementations
3 * of IP-style 1's complement checksum routines.
4 *
5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
13 */
14
15#include <linux/sys.h>
16#include <asm/processor.h>
17#include <asm/errno.h>
18#include <asm/ppc_asm.h>
19
20 .text
21
22/*
23 * ip_fast_csum(buf, len) -- Optimized for IP header
24 * len is in words and is always >= 5.
25 */
26_GLOBAL(ip_fast_csum)
27 lwz r0,0(r3)
28 lwzu r5,4(r3)
29 addic. r4,r4,-2
30 addc r0,r0,r5
31 mtctr r4
32 blelr-
331: lwzu r4,4(r3)
34 adde r0,r0,r4
35 bdnz 1b
36 addze r0,r0 /* add in final carry */
37 rlwinm r3,r0,16,0,31 /* fold two halves together */
38 add r3,r0,r3
39 not r3,r3
40 srwi r3,r3,16
41 blr
42
43/*
44 * Compute checksum of TCP or UDP pseudo-header:
45 * csum_tcpudp_magic(saddr, daddr, len, proto, sum)
46 */
47_GLOBAL(csum_tcpudp_magic)
48 rlwimi r5,r6,16,0,15 /* put proto in upper half of len */
49 addc r0,r3,r4 /* add 4 32-bit words together */
50 adde r0,r0,r5
51 adde r0,r0,r7
52 addze r0,r0 /* add in final carry */
53 rlwinm r3,r0,16,0,31 /* fold two halves together */
54 add r3,r0,r3
55 not r3,r3
56 srwi r3,r3,16
57 blr
58
59/*
60 * computes the checksum of a memory block at buff, length len,
61 * and adds in "sum" (32-bit)
62 *
63 * csum_partial(buff, len, sum)
64 */
65_GLOBAL(csum_partial)
66 addic r0,r5,0
67 subi r3,r3,4
68 srwi. r6,r4,2
69 beq 3f /* if we're doing < 4 bytes */
70 andi. r5,r3,2 /* Align buffer to longword boundary */
71 beq+ 1f
72 lhz r5,4(r3) /* do 2 bytes to get aligned */
73 addi r3,r3,2
74 subi r4,r4,2
75 addc r0,r0,r5
76 srwi. r6,r4,2 /* # words to do */
77 beq 3f
781: mtctr r6
792: lwzu r5,4(r3) /* the bdnz has zero overhead, so it should */
80 adde r0,r0,r5 /* be unnecessary to unroll this loop */
81 bdnz 2b
82 andi. r4,r4,3
833: cmpwi 0,r4,2
84 blt+ 4f
85 lhz r5,4(r3)
86 addi r3,r3,2
87 subi r4,r4,2
88 adde r0,r0,r5
894: cmpwi 0,r4,1
90 bne+ 5f
91 lbz r5,4(r3)
92 slwi r5,r5,8 /* Upper byte of word */
93 adde r0,r0,r5
945: addze r3,r0 /* add in final carry */
95 blr
96
97/*
98 * Computes the checksum of a memory block at src, length len,
99 * and adds in "sum" (32-bit), while copying the block to dst.
100 * If an access exception occurs on src or dst, it stores -EFAULT
101 * to *src_err or *dst_err respectively, and (for an error on
102 * src) zeroes the rest of dst.
103 *
104 * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
105 */
106_GLOBAL(csum_partial_copy_generic)
107 addic r0,r6,0
108 subi r3,r3,4
109 subi r4,r4,4
110 srwi. r6,r5,2
111 beq 3f /* if we're doing < 4 bytes */
112 andi. r9,r4,2 /* Align dst to longword boundary */
113 beq+ 1f
11481: lhz r6,4(r3) /* do 2 bytes to get aligned */
115 addi r3,r3,2
116 subi r5,r5,2
11791: sth r6,4(r4)
118 addi r4,r4,2
119 addc r0,r0,r6
120 srwi. r6,r5,2 /* # words to do */
121 beq 3f
1221: srwi. r6,r5,4 /* # groups of 4 words to do */
123 beq 10f
124 mtctr r6
12571: lwz r6,4(r3)
12672: lwz r9,8(r3)
12773: lwz r10,12(r3)
12874: lwzu r11,16(r3)
129 adde r0,r0,r6
13075: stw r6,4(r4)
131 adde r0,r0,r9
13276: stw r9,8(r4)
133 adde r0,r0,r10
13477: stw r10,12(r4)
135 adde r0,r0,r11
13678: stwu r11,16(r4)
137 bdnz 71b
13810: rlwinm. r6,r5,30,30,31 /* # words left to do */
139 beq 13f
140 mtctr r6
14182: lwzu r9,4(r3)
14292: stwu r9,4(r4)
143 adde r0,r0,r9
144 bdnz 82b
14513: andi. r5,r5,3
1463: cmpwi 0,r5,2
147 blt+ 4f
14883: lhz r6,4(r3)
149 addi r3,r3,2
150 subi r5,r5,2
15193: sth r6,4(r4)
152 addi r4,r4,2
153 adde r0,r0,r6
1544: cmpwi 0,r5,1
155 bne+ 5f
15684: lbz r6,4(r3)
15794: stb r6,4(r4)
158 slwi r6,r6,8 /* Upper byte of word */
159 adde r0,r0,r6
1605: addze r3,r0 /* add in final carry */
161 blr
162
163/* These shouldn't go in the fixup section, since that would
164 cause the ex_table addresses to get out of order. */
165
166src_error_4:
167 mfctr r6 /* update # bytes remaining from ctr */
168 rlwimi r5,r6,4,0,27
169 b 79f
170src_error_1:
171 li r6,0
172 subi r5,r5,2
17395: sth r6,4(r4)
174 addi r4,r4,2
17579: srwi. r6,r5,2
176 beq 3f
177 mtctr r6
178src_error_2:
179 li r6,0
18096: stwu r6,4(r4)
181 bdnz 96b
1823: andi. r5,r5,3
183 beq src_error
184src_error_3:
185 li r6,0
186 mtctr r5
187 addi r4,r4,3
18897: stbu r6,1(r4)
189 bdnz 97b
190src_error:
191 cmpwi 0,r7,0
192 beq 1f
193 li r6,-EFAULT
194 stw r6,0(r7)
1951: addze r3,r0
196 blr
197
198dst_error:
199 cmpwi 0,r8,0
200 beq 1f
201 li r6,-EFAULT
202 stw r6,0(r8)
2031: addze r3,r0
204 blr
205
206.section __ex_table,"a"
207 .long 81b,src_error_1
208 .long 91b,dst_error
209 .long 71b,src_error_4
210 .long 72b,src_error_4
211 .long 73b,src_error_4
212 .long 74b,src_error_4
213 .long 75b,dst_error
214 .long 76b,dst_error
215 .long 77b,dst_error
216 .long 78b,dst_error
217 .long 82b,src_error_2
218 .long 92b,dst_error
219 .long 83b,src_error_3
220 .long 93b,dst_error
221 .long 84b,src_error_3
222 .long 94b,dst_error
223 .long 95b,dst_error
224 .long 96b,dst_error
225 .long 97b,dst_error
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-18 14:10:43 -0500