| blob | 10b45909610ca6f4ca6f6f8bdc664b79c2f2bd6f |
1 /*
2 * linux/arch/arm/lib/csumpartialcopygeneric.S
3 *
4 * Copyright (C) 1995-2001 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10 #include <asm/assembler.h>
12 /*
13 * unsigned int
14 * csum_partial_copy_xxx(const char *src, char *dst, int len, int sum, )
15 * r0 = src, r1 = dst, r2 = len, r3 = sum
16 * Returns : r0 = checksum
17 *
18 * Note that 'tst' and 'teq' preserve the carry flag.
19 */
21 src .req r0
22 dst .req r1
23 len .req r2
24 sum .req r3
26 .Lzero: mov r0, sum
27 load_regs
29 /*
30 * Align an unaligned destination pointer. We know that
31 * we have >= 8 bytes here, so we don't need to check
32 * the length. Note that the source pointer hasn't been
33 * aligned yet.
34 */
35 .Ldst_unaligned:
36 tst dst, #1
37 beq .Ldst_16bit
39 load1b ip
40 sub len, len, #1
41 adcs sum, sum, ip, put_byte_1 @ update checksum
42 strb ip, [dst], #1
43 tst dst, #2
44 reteq lr @ dst is now 32bit aligned
46 .Ldst_16bit: load2b r8, ip
47 sub len, len, #2
48 adcs sum, sum, r8, put_byte_0
49 strb r8, [dst], #1
50 adcs sum, sum, ip, put_byte_1
51 strb ip, [dst], #1
52 ret lr @ dst is now 32bit aligned
54 /*
55 * Handle 0 to 7 bytes, with any alignment of source and
56 * destination pointers. Note that when we get here, C = 0
57 */
58 .Lless8: teq len, #0 @ check for zero count
59 beq .Lzero
61 /* we must have at least one byte. */
62 tst dst, #1 @ dst 16-bit aligned
63 beq .Lless8_aligned
65 /* Align dst */
66 load1b ip
67 sub len, len, #1
68 adcs sum, sum, ip, put_byte_1 @ update checksum
69 strb ip, [dst], #1
70 tst len, #6
71 beq .Lless8_byteonly
73 1: load2b r8, ip
74 sub len, len, #2
75 adcs sum, sum, r8, put_byte_0
76 strb r8, [dst], #1
77 adcs sum, sum, ip, put_byte_1
78 strb ip, [dst], #1
79 .Lless8_aligned:
80 tst len, #6
81 bne 1b
82 .Lless8_byteonly:
83 tst len, #1
84 beq .Ldone
85 load1b r8
86 adcs sum, sum, r8, put_byte_0 @ update checksum
87 strb r8, [dst], #1
88 b .Ldone
90 FN_ENTRY
91 save_regs
93 cmp len, #8 @ Ensure that we have at least
94 blo .Lless8 @ 8 bytes to copy.
96 adds sum, sum, #0 @ C = 0
97 tst dst, #3 @ Test destination alignment
98 blne .Ldst_unaligned @ align destination, return here
100 /*
101 * Ok, the dst pointer is now 32bit aligned, and we know
102 * that we must have more than 4 bytes to copy. Note
103 * that C contains the carry from the dst alignment above.
104 */
106 tst src, #3 @ Test source alignment
107 bne .Lsrc_not_aligned
109 /* Routine for src & dst aligned */
111 bics ip, len, #15
112 beq 2f
114 1: load4l r4, r5, r6, r7
115 stmia dst!, {r4, r5, r6, r7}
116 adcs sum, sum, r4
117 adcs sum, sum, r5
118 adcs sum, sum, r6
119 adcs sum, sum, r7
120 sub ip, ip, #16
121 teq ip, #0
122 bne 1b
124 2: ands ip, len, #12
125 beq 4f
126 tst ip, #8
127 beq 3f
128 load2l r4, r5
129 stmia dst!, {r4, r5}
130 adcs sum, sum, r4
131 adcs sum, sum, r5
132 tst ip, #4
133 beq 4f
135 3: load1l r4
136 str r4, [dst], #4
137 adcs sum, sum, r4
139 4: ands len, len, #3
140 beq .Ldone
141 load1l r4
142 tst len, #2
143 mov r5, r4, get_byte_0
144 beq .Lexit
145 adcs sum, sum, r4, lspush #16
146 strb r5, [dst], #1
147 mov r5, r4, get_byte_1
148 strb r5, [dst], #1
149 mov r5, r4, get_byte_2
150 .Lexit: tst len, #1
151 strneb r5, [dst], #1
152 andne r5, r5, #255
153 adcnes sum, sum, r5, put_byte_0
155 /*
156 * If the dst pointer was not 16-bit aligned, we
157 * need to rotate the checksum here to get around
158 * the inefficient byte manipulations in the
159 * architecture independent code.
160 */
161 .Ldone: adc r0, sum, #0
162 ldr sum, [sp, #0] @ dst
163 tst sum, #1
164 movne r0, r0, ror #8
165 load_regs
167 .Lsrc_not_aligned:
168 adc sum, sum, #0 @ include C from dst alignment
169 and ip, src, #3
170 bic src, src, #3
171 load1l r5
172 cmp ip, #2
173 beq .Lsrc2_aligned
174 bhi .Lsrc3_aligned
175 mov r4, r5, lspull #8 @ C = 0
176 bics ip, len, #15
177 beq 2f
178 1: load4l r5, r6, r7, r8
179 orr r4, r4, r5, lspush #24
180 mov r5, r5, lspull #8
181 orr r5, r5, r6, lspush #24
182 mov r6, r6, lspull #8
183 orr r6, r6, r7, lspush #24
184 mov r7, r7, lspull #8
185 orr r7, r7, r8, lspush #24
186 stmia dst!, {r4, r5, r6, r7}
187 adcs sum, sum, r4
188 adcs sum, sum, r5
189 adcs sum, sum, r6
190 adcs sum, sum, r7
191 mov r4, r8, lspull #8
192 sub ip, ip, #16
193 teq ip, #0
194 bne 1b
195 2: ands ip, len, #12
196 beq 4f
197 tst ip, #8
198 beq 3f
199 load2l r5, r6
200 orr r4, r4, r5, lspush #24
201 mov r5, r5, lspull #8
202 orr r5, r5, r6, lspush #24
203 stmia dst!, {r4, r5}
204 adcs sum, sum, r4
205 adcs sum, sum, r5
206 mov r4, r6, lspull #8
207 tst ip, #4
208 beq 4f
209 3: load1l r5
210 orr r4, r4, r5, lspush #24
211 str r4, [dst], #4
212 adcs sum, sum, r4
213 mov r4, r5, lspull #8
214 4: ands len, len, #3
215 beq .Ldone
216 mov r5, r4, get_byte_0
217 tst len, #2
218 beq .Lexit
219 adcs sum, sum, r4, lspush #16
220 strb r5, [dst], #1
221 mov r5, r4, get_byte_1
222 strb r5, [dst], #1
223 mov r5, r4, get_byte_2
224 b .Lexit
226 .Lsrc2_aligned: mov r4, r5, lspull #16
227 adds sum, sum, #0
228 bics ip, len, #15
229 beq 2f
230 1: load4l r5, r6, r7, r8
231 orr r4, r4, r5, lspush #16
232 mov r5, r5, lspull #16
233 orr r5, r5, r6, lspush #16
234 mov r6, r6, lspull #16
235 orr r6, r6, r7, lspush #16
236 mov r7, r7, lspull #16
237 orr r7, r7, r8, lspush #16
238 stmia dst!, {r4, r5, r6, r7}
239 adcs sum, sum, r4
240 adcs sum, sum, r5
241 adcs sum, sum, r6
242 adcs sum, sum, r7
243 mov r4, r8, lspull #16
244 sub ip, ip, #16
245 teq ip, #0
246 bne 1b
247 2: ands ip, len, #12
248 beq 4f
249 tst ip, #8
250 beq 3f
251 load2l r5, r6
252 orr r4, r4, r5, lspush #16
253 mov r5, r5, lspull #16
254 orr r5, r5, r6, lspush #16
255 stmia dst!, {r4, r5}
256 adcs sum, sum, r4
257 adcs sum, sum, r5
258 mov r4, r6, lspull #16
259 tst ip, #4
260 beq 4f
261 3: load1l r5
262 orr r4, r4, r5, lspush #16
263 str r4, [dst], #4
264 adcs sum, sum, r4
265 mov r4, r5, lspull #16
266 4: ands len, len, #3
267 beq .Ldone
268 mov r5, r4, get_byte_0
269 tst len, #2
270 beq .Lexit
271 adcs sum, sum, r4
272 strb r5, [dst], #1
273 mov r5, r4, get_byte_1
274 strb r5, [dst], #1
275 tst len, #1
276 beq .Ldone
277 load1b r5
278 b .Lexit
280 .Lsrc3_aligned: mov r4, r5, lspull #24
281 adds sum, sum, #0
282 bics ip, len, #15
283 beq 2f
284 1: load4l r5, r6, r7, r8
285 orr r4, r4, r5, lspush #8
286 mov r5, r5, lspull #24
287 orr r5, r5, r6, lspush #8
288 mov r6, r6, lspull #24
289 orr r6, r6, r7, lspush #8
290 mov r7, r7, lspull #24
291 orr r7, r7, r8, lspush #8
292 stmia dst!, {r4, r5, r6, r7}
293 adcs sum, sum, r4
294 adcs sum, sum, r5
295 adcs sum, sum, r6
296 adcs sum, sum, r7
297 mov r4, r8, lspull #24
298 sub ip, ip, #16
299 teq ip, #0
300 bne 1b
301 2: ands ip, len, #12
302 beq 4f
303 tst ip, #8
304 beq 3f
305 load2l r5, r6
306 orr r4, r4, r5, lspush #8
307 mov r5, r5, lspull #24
308 orr r5, r5, r6, lspush #8
309 stmia dst!, {r4, r5}
310 adcs sum, sum, r4
311 adcs sum, sum, r5
312 mov r4, r6, lspull #24
313 tst ip, #4
314 beq 4f
315 3: load1l r5
316 orr r4, r4, r5, lspush #8
317 str r4, [dst], #4
318 adcs sum, sum, r4
319 mov r4, r5, lspull #24
320 4: ands len, len, #3
321 beq .Ldone
322 mov r5, r4, get_byte_0
323 tst len, #2
324 beq .Lexit
325 strb r5, [dst], #1
326 adcs sum, sum, r4
327 load1l r4
328 mov r5, r4, get_byte_0
329 strb r5, [dst], #1
330 adcs sum, sum, r4, lspush #24
331 mov r5, r4, get_byte_1
332 b .Lexit
333 FN_EXIT