1 /* Copy memory to memory until the specified number of bytes
2 has been copied. Overlap is handled correctly.
3 Copyright (C) 1991, 1995, 1996, 1997, 2003 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Torbjorn Granlund (tege@sics.se).
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <http://www.gnu.org/licenses/>. */
20
21 #include <string.h>
22
23 #include "memcopy.h"
24 #include "pagecopy.h"
25
26 #ifdef __ARCH_HAS_BWD_MEMCPY__
27 /* generic-opt memmove assumes memcpy does forward copying! */
28 #include "_memcpy_fwd.c"
29 #endif
30
31
_wordcopy_bwd_aligned(long int dstp,long int srcp,size_t len)32 static void _wordcopy_bwd_aligned (long int dstp, long int srcp, size_t len)
33 {
34 op_t a0 = 0;
35 op_t a1 = 0;
36
37 switch (len % 8)
38 {
39 case 2:
40 srcp -= 2 * OPSIZ;
41 dstp -= 1 * OPSIZ;
42 a0 = ((op_t *) srcp)[1];
43 len += 6;
44 goto do1;
45 case 3:
46 srcp -= 3 * OPSIZ;
47 dstp -= 2 * OPSIZ;
48 a1 = ((op_t *) srcp)[2];
49 len += 5;
50 goto do2;
51 case 4:
52 srcp -= 4 * OPSIZ;
53 dstp -= 3 * OPSIZ;
54 a0 = ((op_t *) srcp)[3];
55 len += 4;
56 goto do3;
57 case 5:
58 srcp -= 5 * OPSIZ;
59 dstp -= 4 * OPSIZ;
60 a1 = ((op_t *) srcp)[4];
61 len += 3;
62 goto do4;
63 case 6:
64 srcp -= 6 * OPSIZ;
65 dstp -= 5 * OPSIZ;
66 a0 = ((op_t *) srcp)[5];
67 len += 2;
68 goto do5;
69 case 7:
70 srcp -= 7 * OPSIZ;
71 dstp -= 6 * OPSIZ;
72 a1 = ((op_t *) srcp)[6];
73 len += 1;
74 goto do6;
75
76 case 0:
77 if (OP_T_THRES <= 3 * OPSIZ && len == 0)
78 return;
79 srcp -= 8 * OPSIZ;
80 dstp -= 7 * OPSIZ;
81 a0 = ((op_t *) srcp)[7];
82 goto do7;
83 case 1:
84 srcp -= 9 * OPSIZ;
85 dstp -= 8 * OPSIZ;
86 a1 = ((op_t *) srcp)[8];
87 len -= 1;
88 if (OP_T_THRES <= 3 * OPSIZ && len == 0)
89 goto do0;
90 goto do8; /* No-op. */
91 }
92
93 do
94 {
95 do8:
96 a0 = ((op_t *) srcp)[7];
97 ((op_t *) dstp)[7] = a1;
98 do7:
99 a1 = ((op_t *) srcp)[6];
100 ((op_t *) dstp)[6] = a0;
101 do6:
102 a0 = ((op_t *) srcp)[5];
103 ((op_t *) dstp)[5] = a1;
104 do5:
105 a1 = ((op_t *) srcp)[4];
106 ((op_t *) dstp)[4] = a0;
107 do4:
108 a0 = ((op_t *) srcp)[3];
109 ((op_t *) dstp)[3] = a1;
110 do3:
111 a1 = ((op_t *) srcp)[2];
112 ((op_t *) dstp)[2] = a0;
113 do2:
114 a0 = ((op_t *) srcp)[1];
115 ((op_t *) dstp)[1] = a1;
116 do1:
117 a1 = ((op_t *) srcp)[0];
118 ((op_t *) dstp)[0] = a0;
119
120 srcp -= 8 * OPSIZ;
121 dstp -= 8 * OPSIZ;
122 len -= 8;
123 }
124 while (len != 0);
125
126 /* This is the right position for do0. Please don't move
127 it into the loop. */
128 do0:
129 ((op_t *) dstp)[7] = a1;
130 }
131
132 /* _wordcopy_bwd_dest_aligned -- Copy block finishing right
133 before SRCP to block finishing right before DSTP with LEN `op_t'
134 words (not LEN bytes!). DSTP should be aligned for memory
135 operations on `op_t', but SRCP must *not* be aligned. */
136
_wordcopy_bwd_dest_aligned(long int dstp,long int srcp,size_t len)137 static void _wordcopy_bwd_dest_aligned (long int dstp, long int srcp, size_t len)
138 {
139 op_t a0 = 0;
140 op_t a1 = 0;
141 op_t a2 = 0;
142 op_t a3 = 0;
143 int sh_1, sh_2;
144
145 /* Calculate how to shift a word read at the memory operation
146 aligned srcp to make it aligned for copy. */
147
148 sh_1 = 8 * (srcp % OPSIZ);
149 sh_2 = 8 * OPSIZ - sh_1;
150
151 /* Make srcp aligned by rounding it down to the beginning of the op_t
152 it points in the middle of. */
153 srcp &= -OPSIZ;
154 srcp += OPSIZ;
155
156 switch (len % 4)
157 {
158 case 2:
159 srcp -= 3 * OPSIZ;
160 dstp -= 1 * OPSIZ;
161 a2 = ((op_t *) srcp)[2];
162 a1 = ((op_t *) srcp)[1];
163 len += 2;
164 goto do1;
165 case 3:
166 srcp -= 4 * OPSIZ;
167 dstp -= 2 * OPSIZ;
168 a3 = ((op_t *) srcp)[3];
169 a2 = ((op_t *) srcp)[2];
170 len += 1;
171 goto do2;
172 case 0:
173 if (OP_T_THRES <= 3 * OPSIZ && len == 0)
174 return;
175 srcp -= 5 * OPSIZ;
176 dstp -= 3 * OPSIZ;
177 a0 = ((op_t *) srcp)[4];
178 a3 = ((op_t *) srcp)[3];
179 goto do3;
180 case 1:
181 srcp -= 6 * OPSIZ;
182 dstp -= 4 * OPSIZ;
183 a1 = ((op_t *) srcp)[5];
184 a0 = ((op_t *) srcp)[4];
185 len -= 1;
186 if (OP_T_THRES <= 3 * OPSIZ && len == 0)
187 goto do0;
188 goto do4; /* No-op. */
189 }
190
191 do
192 {
193 do4:
194 a3 = ((op_t *) srcp)[3];
195 ((op_t *) dstp)[3] = MERGE (a0, sh_1, a1, sh_2);
196 do3:
197 a2 = ((op_t *) srcp)[2];
198 ((op_t *) dstp)[2] = MERGE (a3, sh_1, a0, sh_2);
199 do2:
200 a1 = ((op_t *) srcp)[1];
201 ((op_t *) dstp)[1] = MERGE (a2, sh_1, a3, sh_2);
202 do1:
203 a0 = ((op_t *) srcp)[0];
204 ((op_t *) dstp)[0] = MERGE (a1, sh_1, a2, sh_2);
205
206 srcp -= 4 * OPSIZ;
207 dstp -= 4 * OPSIZ;
208 len -= 4;
209 }
210 while (len != 0);
211
212 /* This is the right position for do0. Please don't move
213 it into the loop. */
214 do0:
215 ((op_t *) dstp)[3] = MERGE (a0, sh_1, a1, sh_2);
216 }
217
memmove(void * dest,const void * src,size_t len)218 void *memmove (void *dest, const void *src, size_t len)
219 {
220 unsigned long int dstp = (long int) dest;
221 unsigned long int srcp = (long int) src;
222
223 /* This test makes the forward copying code be used whenever possible.
224 Reduces the working set. */
225 if (dstp - srcp >= len) /* *Unsigned* compare! */
226 {
227 #ifndef __ARCH_HAS_BWD_MEMCPY__
228 /* Backward memcpy implementation cannot be used */
229 memcpy(dest, src, len);
230 #else
231 /* Copy from the beginning to the end. */
232
233 /* If there not too few bytes to copy, use word copy. */
234 if (len >= OP_T_THRES)
235 {
236 /* Copy just a few bytes to make DSTP aligned. */
237 len -= (-dstp) % OPSIZ;
238 BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
239
240 /* Copy whole pages from SRCP to DSTP by virtual address
241 manipulation, as much as possible. */
242
243 PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
244
245 /* Copy from SRCP to DSTP taking advantage of the known
246 alignment of DSTP. Number of bytes remaining is put
247 in the third argument, i.e. in LEN. This number may
248 vary from machine to machine. */
249
250 WORD_COPY_FWD (dstp, srcp, len, len);
251
252 /* Fall out and copy the tail. */
253 }
254
255 /* There are just a few bytes to copy. Use byte memory operations. */
256 BYTE_COPY_FWD (dstp, srcp, len);
257 #endif
258 }
259 else
260 {
261 /* Copy from the end to the beginning. */
262 srcp += len;
263 dstp += len;
264
265 /* If there not too few bytes to copy, use word copy. */
266 if (len >= OP_T_THRES)
267 {
268 /* Copy just a few bytes to make DSTP aligned. */
269 len -= dstp % OPSIZ;
270 BYTE_COPY_BWD (dstp, srcp, dstp % OPSIZ);
271
272 /* Copy from SRCP to DSTP taking advantage of the known
273 alignment of DSTP. Number of bytes remaining is put
274 in the third argument, i.e. in LEN. This number may
275 vary from machine to machine. */
276
277 WORD_COPY_BWD (dstp, srcp, len, len);
278
279 /* Fall out and copy the tail. */
280 }
281
282 /* There are just a few bytes to copy. Use byte memory operations. */
283 BYTE_COPY_BWD (dstp, srcp, len);
284 }
285
286 return (dest);
287 }
288 libc_hidden_weak(memmove)
289