tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 * computes the checksum of a memory block at buff, length len,
45 * and adds in "sum" (32-bit)
46 *
47 * csum_partial(buff, len, sum)
48 */
49_GLOBAL(csum_partial)
50 addic r0,r5,0
51 subi r3,r3,4
52 srwi. r6,r4,2
53 beq 3f /* if we're doing < 4 bytes */
54 andi. r5,r3,2 /* Align buffer to longword boundary */
55 beq+ 1f
56 lhz r5,4(r3) /* do 2 bytes to get aligned */
57 addi r3,r3,2
58 subi r4,r4,2
59 addc r0,r0,r5
60 srwi. r6,r4,2 /* # words to do */
61 beq 3f
621: mtctr r6
632: lwzu r5,4(r3) /* the bdnz has zero overhead, so it should */
64 adde r0,r0,r5 /* be unnecessary to unroll this loop */
65 bdnz 2b
66 andi. r4,r4,3
673: cmpwi 0,r4,2
68 blt+ 4f
69 lhz r5,4(r3)
70 addi r3,r3,2
71 subi r4,r4,2
72 adde r0,r0,r5
734: cmpwi 0,r4,1
74 bne+ 5f
75 lbz r5,4(r3)
76 slwi r5,r5,8 /* Upper byte of word */
77 adde r0,r0,r5
785: addze r3,r0 /* add in final carry */
79 blr
80
81/*
82 * Computes the checksum of a memory block at src, length len,
83 * and adds in "sum" (32-bit), while copying the block to dst.
84 * If an access exception occurs on src or dst, it stores -EFAULT
85 * to *src_err or *dst_err respectively, and (for an error on
86 * src) zeroes the rest of dst.
87 *
88 * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
89 */
90_GLOBAL(csum_partial_copy_generic)
91 addic r0,r6,0
92 subi r3,r3,4
93 subi r4,r4,4
94 srwi. r6,r5,2
95 beq 3f /* if we're doing < 4 bytes */
96 andi. r9,r4,2 /* Align dst to longword boundary */
97 beq+ 1f
9881: lhz r6,4(r3) /* do 2 bytes to get aligned */
99 addi r3,r3,2
100 subi r5,r5,2
10191: sth r6,4(r4)
102 addi r4,r4,2
103 addc r0,r0,r6
104 srwi. r6,r5,2 /* # words to do */
105 beq 3f
1061: srwi. r6,r5,4 /* # groups of 4 words to do */
107 beq 10f
108 mtctr r6
10971: lwz r6,4(r3)
11072: lwz r9,8(r3)
11173: lwz r10,12(r3)
11274: lwzu r11,16(r3)
113 adde r0,r0,r6
11475: stw r6,4(r4)
115 adde r0,r0,r9
11676: stw r9,8(r4)
117 adde r0,r0,r10
11877: stw r10,12(r4)
119 adde r0,r0,r11
12078: stwu r11,16(r4)
121 bdnz 71b
12210: rlwinm. r6,r5,30,30,31 /* # words left to do */
123 beq 13f
124 mtctr r6
12582: lwzu r9,4(r3)
12692: stwu r9,4(r4)
127 adde r0,r0,r9
128 bdnz 82b
12913: andi. r5,r5,3
1303: cmpwi 0,r5,2
131 blt+ 4f
13283: lhz r6,4(r3)
133 addi r3,r3,2
134 subi r5,r5,2
13593: sth r6,4(r4)
136 addi r4,r4,2
137 adde r0,r0,r6
1384: cmpwi 0,r5,1
139 bne+ 5f
14084: lbz r6,4(r3)
14194: stb r6,4(r4)
142 slwi r6,r6,8 /* Upper byte of word */
143 adde r0,r0,r6
1445: addze r3,r0 /* add in final carry */
145 blr
146
147/* These shouldn't go in the fixup section, since that would
148 cause the ex_table addresses to get out of order. */
149
150src_error_4:
151 mfctr r6 /* update # bytes remaining from ctr */
152 rlwimi r5,r6,4,0,27
153 b 79f
154src_error_1:
155 li r6,0
156 subi r5,r5,2
15795: sth r6,4(r4)
158 addi r4,r4,2
15979: srwi. r6,r5,2
160 beq 3f
161 mtctr r6
162src_error_2:
163 li r6,0
16496: stwu r6,4(r4)
165 bdnz 96b
1663: andi. r5,r5,3
167 beq src_error
168src_error_3:
169 li r6,0
170 mtctr r5
171 addi r4,r4,3
17297: stbu r6,1(r4)
173 bdnz 97b
174src_error:
175 cmpwi 0,r7,0
176 beq 1f
177 li r6,-EFAULT
178 stw r6,0(r7)
1791: addze r3,r0
180 blr
181
182dst_error:
183 cmpwi 0,r8,0
184 beq 1f
185 li r6,-EFAULT
186 stw r6,0(r8)
1871: addze r3,r0
188 blr
189
190.section __ex_table,"a"
191 .long 81b,src_error_1
192 .long 91b,dst_error
193 .long 71b,src_error_4
194 .long 72b,src_error_4
195 .long 73b,src_error_4
196 .long 74b,src_error_4
197 .long 75b,dst_error
198 .long 76b,dst_error
199 .long 77b,dst_error
200 .long 78b,dst_error
201 .long 82b,src_error_2
202 .long 92b,dst_error
203 .long 83b,src_error_3
204 .long 93b,dst_error
205 .long 84b,src_error_3
206 .long 94b,dst_error
207 .long 95b,dst_error
208 .long 96b,dst_error
209 .long 97b,dst_error