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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [arch/] [m68k/] [lib/] [checksum.c] - Blame information for rev 1765

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Line No. Rev Author Line
1 199 simons 
/*
2 
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
3 
 *              operating system.  INET is implemented using the  BSD Socket
4 
 *              interface as the means of communication with the user level.
5 
 *
6 
 *              IP/TCP/UDP checksumming routines
7 
 *
8 
 * Authors:     Jorge Cwik, <jorge@laser.satlink.net>
9 
 *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
10 
 *              Tom May, <ftom@netcom.com>
11 
 *              Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>
12 
 *              Lots of code moved from tcp.c and ip.c; see those files
13 
 *              for more names.
14 
 *
15 
 * 03/02/96     Jes Sorensen, Andreas Schwab, Roman Hodek:
16 
 *              Fixed some nasty bugs, causing some horrible crashes.
17 
 *              A: At some points, the sum (%0) was used as
18 
 *              length-counter instead of the length counter
19 
 *              (%1). Thanks to Roman Hodek for pointing this out.
20 
 *              B: GCC seems to mess up if one uses too many
21 
 *              data-registers to hold input values and one tries to
22 
 *              specify d0 and d1 as scratch registers. Letting gcc choose these
23 
 *      registers itself solves the problem.
24 
 *
25 
 *              This program is free software; you can redistribute it and/or
26 
 *              modify it under the terms of the GNU General Public License
27 
 *              as published by the Free Software Foundation; either version
28 
 *              2 of the License, or (at your option) any later version.
29 
 */
30 
 
31 
#include <net/checksum.h>
32 
 
33 
/*
34 
 * computes a partial checksum, e.g. for TCP/UDP fragments
35 
 */
36 
 
37 
unsigned int
38 
csum_partial (const unsigned char *buff, int len, unsigned int sum)
39 
{
40 
        unsigned long tmp1, tmp2;
41 
          /*
42 
           * Experiments with ethernet and slip connections show that buff
43 
           * is aligned on either a 2-byte or 4-byte boundary.
44 
           */
45 
        __asm__("movel %2,%3\n\t"
46 
                "btst #1,%3\n\t"        /* Check alignment */
47 
                "jeq 2f\n\t"
48 
                "subql #2,%1\n\t"       /* buff%4==2: treat first word */
49 
                "jgt 1f\n\t"
50 
                "addql #2,%1\n\t"       /* len was == 2, treat only rest */
51 
                "jra 4f\n"
52 
             "1:\t"
53 
                "addw %2@+,%0\n\t"      /* add first word to sum */
54 
                "clrl %3\n\t"
55 
                "addxl %3,%0\n"         /* add X bit */
56 
             "2:\t"
57 
                /* unrolled loop for the main part: do 8 longs at once */
58 
                "movel %1,%3\n\t"       /* save len in tmp1 */
59 
                "lsrl #5,%1\n\t"        /* len/32 */
60 
                "jeq 2f\n\t"            /* not enough... */
61 
                "subql #1,%1\n"
62 
             "1:\t"
63 
                "movel %2@+,%4\n\t"
64 
                "addxl %4,%0\n\t"
65 
                "movel %2@+,%4\n\t"
66 
                "addxl %4,%0\n\t"
67 
                "movel %2@+,%4\n\t"
68 
                "addxl %4,%0\n\t"
69 
                "movel %2@+,%4\n\t"
70 
                "addxl %4,%0\n\t"
71 
                "movel %2@+,%4\n\t"
72 
                "addxl %4,%0\n\t"
73 
                "movel %2@+,%4\n\t"
74 
                "addxl %4,%0\n\t"
75 
                "movel %2@+,%4\n\t"
76 
                "addxl %4,%0\n\t"
77 
                "movel %2@+,%4\n\t"
78 
                "addxl %4,%0\n\t"
79 
                "dbra %1,1b\n\t"
80 
                "clrl %4\n\t"
81 
                "addxl %4,%0\n\t"       /* add X bit */
82 
                "clrw %1\n\t"
83 
                "subql #1,%1\n\t"
84 
                "jcc 1b\n"
85 
             "2:\t"
86 
                "movel %3,%1\n\t"       /* restore len from tmp1 */
87 
                "andw #0x1c,%3\n\t"     /* number of rest longs */
88 
                "jeq 4f\n\t"
89 
                "lsrw #2,%3\n\t"
90 
                "subqw #1,%3\n"
91 
             "3:\t"
92 
                /* loop for rest longs */
93 
                "movel %2@+,%4\n\t"
94 
                "addxl %4,%0\n\t"
95 
                "dbra %3,3b\n\t"
96 
                "clrl %4\n\t"
97 
                "addxl %4,%0\n"         /* add X bit */
98 
             "4:\t"
99 
                /* now check for rest bytes that do not fit into longs */
100 
                "andw #3,%1\n\t"
101 
                "jeq 7f\n\t"
102 
                "clrl %4\n\t"           /* clear tmp2 for rest bytes */
103 
                "subqw #2,%1\n\t"
104 
                "jlt 5f\n\t"
105 
                "movew %2@+,%4\n\t"     /* have rest >= 2: get word */
106 
                "swap %4\n\t"           /* into bits 16..31 */
107 
                "tstw %1\n\t"           /* another byte? */
108 
                "jeq 6f\n"
109 
             "5:\t"
110 
                "moveb %2@,%4\n\t"      /* have odd rest: get byte */
111 
                "lslw #8,%4\n\t"        /* into bits 8..15; 16..31 untouched */
112 
             "6:\t"
113 
                "addl %4,%0\n\t"        /* now add rest long to sum */
114 
                "clrl %4\n\t"
115 
                "addxl %4,%0\n"         /* add X bit */
116 
             "7:\t"
117 
                : "=d" (sum), "=d" (len), "=a" (buff),
118 
                  "=&d" (tmp1), "=&d" (tmp2)
119 
                : "0" (sum), "1" (len), "2" (buff)
120 
            );
121 
        return(sum);
122 
}
123 
 
124 
 
125 
 
126 
/*
127 
 * copy from fs while checksumming, otherwise like csum_partial
128 
 */
129 
 
130 
unsigned int
131 
csum_partial_copy_fromuser(const char *src, char *dst, int len, int sum)
132 
{
133 
        unsigned long tmp1, tmp2;
134 
        __asm__("movel %2,%4\n\t"
135 
                "btst #1,%4\n\t"        /* Check alignment */
136 
                "jeq 2f\n\t"
137 
                "subql #2,%1\n\t"       /* buff%4==2: treat first word */
138 
                "jgt 1f\n\t"
139 
                "addql #2,%1\n\t"       /* len was == 2, treat only rest */
140 
                "jra 4f\n"
141 
             "1:\t"
142 
                "movesw %2@+,%4\n\t"    /* add first word to sum */
143 
                "addw %4,%0\n\t"
144 
                "movew %4,%3@+\n\t"
145 
                "clrl %4\n\t"
146 
                "addxl %4,%0\n"         /* add X bit */
147 
             "2:\t"
148 
                /* unrolled loop for the main part: do 8 longs at once */
149 
                "movel %1,%4\n\t"       /* save len in tmp1 */
150 
                "lsrl #5,%1\n\t"        /* len/32 */
151 
                "jeq 2f\n\t"            /* not enough... */
152 
                "subql #1,%1\n"
153 
             "1:\t"
154 
                "movesl %2@+,%5\n\t"
155 
                "addxl %5,%0\n\t"
156 
                "movel %5,%3@+\n\t"
157 
                "movesl %2@+,%5\n\t"
158 
                "addxl %5,%0\n\t"
159 
                "movel %5,%3@+\n\t"
160 
                "movesl %2@+,%5\n\t"
161 
                "addxl %5,%0\n\t"
162 
                "movel %5,%3@+\n\t"
163 
                "movesl %2@+,%5\n\t"
164 
                "addxl %5,%0\n\t"
165 
                "movel %5,%3@+\n\t"
166 
                "movesl %2@+,%5\n\t"
167 
                "addxl %5,%0\n\t"
168 
                "movel %5,%3@+\n\t"
169 
                "movesl %2@+,%5\n\t"
170 
                "addxl %5,%0\n\t"
171 
                "movel %5,%3@+\n\t"
172 
                "movesl %2@+,%5\n\t"
173 
                "addxl %5,%0\n\t"
174 
                "movel %5,%3@+\n\t"
175 
                "movesl %2@+,%5\n\t"
176 
                "addxl %5,%0\n\t"
177 
                "movel %5,%3@+\n\t"
178 
                "dbra %1,1b\n\t"
179 
                "clrl %5\n\t"
180 
                "addxl %5,%0\n\t"       /* add X bit */
181 
                "clrw %1\n\t"
182 
                "subql #1,%1\n\t"
183 
                "jcc 1b\n"
184 
             "2:\t"
185 
                "movel %4,%1\n\t"       /* restore len from tmp1 */
186 
                "andw #0x1c,%4\n\t"     /* number of rest longs */
187 
                "jeq 4f\n\t"
188 
                "lsrw #2,%4\n\t"
189 
                "subqw #1,%4\n"
190 
             "3:\t"
191 
                /* loop for rest longs */
192 
                "movesl %2@+,%5\n\t"
193 
                "addxl %5,%0\n\t"
194 
                "movel %5,%3@+\n\t"
195 
                "dbra %4,3b\n\t"
196 
                "clrl %5\n\t"
197 
                "addxl %5,%0\n"         /* add X bit */
198 
             "4:\t"
199 
                /* now check for rest bytes that do not fit into longs */
200 
                "andw #3,%1\n\t"
201 
                "jeq 7f\n\t"
202 
                "clrl %5\n\t"           /* clear tmp2 for rest bytes */
203 
                "subqw #2,%1\n\t"
204 
                "jlt 5f\n\t"
205 
                "movesw %2@+,%5\n\t"    /* have rest >= 2: get word */
206 
                "movew %5,%3@+\n\t"
207 
                "swap %5\n\t"           /* into bits 16..31 */
208 
                "tstw %1\n\t"           /* another byte? */
209 
                "jeq 6f\n"
210 
             "5:\t"
211 
                "movesb %2@,%5\n\t"     /* have odd rest: get byte */
212 
                "moveb %5,%3@+\n\t"
213 
                "lslw #8,%5\n\t"        /* into bits 8..15; 16..31 untouched */
214 
             "6:\t"
215 
                "addl %5,%0\n\t"        /* now add rest long to sum */
216 
                "clrl %5\n\t"
217 
                "addxl %5,%0\n"         /* add X bit */
218 
             "7:\t"
219 
                : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
220 
                  "=&d" (tmp1), "=&d" (tmp2)
221 
                : "0" (sum), "1" (len), "2" (src), "3" (dst)
222 
            );
223 
        return(sum);
224 
}
225 
/*
226 
 * copy from ds while checksumming, otherwise like csum_partial
227 
 */
228 
 
229 
unsigned int
230 
csum_partial_copy(const char *src, char *dst, int len, int sum)
231 
{
232 
        unsigned long tmp1, tmp2;
233 
        __asm__("movel %2,%4\n\t"
234 
                "btst #1,%4\n\t"        /* Check alignment */
235 
                "jeq 2f\n\t"
236 
                "subql #2,%1\n\t"       /* buff%4==2: treat first word */
237 
                "jgt 1f\n\t"
238 
                "addql #2,%1\n\t"       /* len was == 2, treat only rest */
239 
                "jra 4f\n"
240 
             "1:\t"
241 
                "movew %2@+,%4\n\t"     /* add first word to sum */
242 
                "addw %4,%0\n\t"
243 
                "movew %4,%3@+\n\t"
244 
                "clrl %4\n\t"
245 
                "addxl %4,%0\n"         /* add X bit */
246 
             "2:\t"
247 
                /* unrolled loop for the main part: do 8 longs at once */
248 
                "movel %1,%4\n\t"       /* save len in tmp1 */
249 
                "lsrl #5,%1\n\t"        /* len/32 */
250 
                "jeq 2f\n\t"            /* not enough... */
251 
                "subql #1,%1\n"
252 
             "1:\t"
253 
                "movel %2@+,%5\n\t"
254 
                "addxl %5,%0\n\t"
255 
                "movel %5,%3@+\n\t"
256 
                "movel %2@+,%5\n\t"
257 
                "addxl %5,%0\n\t"
258 
                "movel %5,%3@+\n\t"
259 
                "movel %2@+,%5\n\t"
260 
                "addxl %5,%0\n\t"
261 
                "movel %5,%3@+\n\t"
262 
                "movel %2@+,%5\n\t"
263 
                "addxl %5,%0\n\t"
264 
                "movel %5,%3@+\n\t"
265 
                "movel %2@+,%5\n\t"
266 
                "addxl %5,%0\n\t"
267 
                "movel %5,%3@+\n\t"
268 
                "movel %2@+,%5\n\t"
269 
                "addxl %5,%0\n\t"
270 
                "movel %5,%3@+\n\t"
271 
                "movel %2@+,%5\n\t"
272 
                "addxl %5,%0\n\t"
273 
                "movel %5,%3@+\n\t"
274 
                "movel %2@+,%5\n\t"
275 
                "addxl %5,%0\n\t"
276 
                "movel %5,%3@+\n\t"
277 
                "dbra %1,1b\n\t"
278 
                "clrl %5\n\t"
279 
                "addxl %5,%0\n\t"       /* add X bit */
280 
                "clrw %1\n\t"
281 
                "subql #1,%1\n\t"
282 
                "jcc 1b\n"
283 
             "2:\t"
284 
                "movel %4,%1\n\t"       /* restore len from tmp1 */
285 
                "andw #0x1c,%4\n\t"     /* number of rest longs */
286 
                "jeq 4f\n\t"
287 
                "lsrw #2,%4\n\t"
288 
                "subqw #1,%4\n"
289 
             "3:\t"
290 
                /* loop for rest longs */
291 
                "movel %2@+,%5\n\t"
292 
                "addxl %5,%0\n\t"
293 
                "movel %5,%3@+\n\t"
294 
                "dbra %4,3b\n\t"
295 
                "clrl %5\n\t"
296 
                "addxl %5,%0\n"         /* add X bit */
297 
             "4:\t"
298 
                /* now check for rest bytes that do not fit into longs */
299 
                "andw #3,%1\n\t"
300 
                "jeq 7f\n\t"
301 
                "clrl %5\n\t"           /* clear tmp2 for rest bytes */
302 
                "subqw #2,%1\n\t"
303 
                "jlt 5f\n\t"
304 
                "movew %2@+,%5\n\t"     /* have rest >= 2: get word */
305 
                "movew %5,%3@+\n\t"
306 
                "swap %5\n\t"           /* into bits 16..31 */
307 
                "tstw %1\n\t"           /* another byte? */
308 
                "jeq 6f\n"
309 
             "5:\t"
310 
                "moveb %2@,%5\n\t"      /* have odd rest: get byte */
311 
                "moveb %5,%3@+\n\t"
312 
                "lslw #8,%5\n"          /* into bits 8..15; 16..31 untouched */
313 
             "6:\t"
314 
                "addl %5,%0\n\t"        /* now add rest long to sum */
315 
                "clrl %5\n\t"
316 
                "addxl %5,%0\n"         /* add X bit */
317 
             "7:\t"
318 
                : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
319 
                  "=&d" (tmp1), "=&d" (tmp2)
320 
                : "0" (sum), "1" (len), "2" (src), "3" (dst)
321 
            );
322 
    return(sum);
323 
}

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