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1 | /* Copy memory to memory until the specified number of bytes | |
2 | has been copied with error checking. Overlap is handled correctly. | |
3 | Copyright (C) 1991,1995,1996,1997,2003,2004 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, write to the Free | |
19 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
20 | 02111-1307 USA. */ | |
21 | ||
22 | #include <string.h> | |
23 | #include <memcopy.h> | |
24 | #include <pagecopy.h> | |
25 | ||
26 | void * | |
27 | __memmove_chk (dest, src, len, destlen) | |
28 | void *dest; | |
29 | const void *src; | |
30 | size_t len; | |
31 | size_t destlen; | |
32 | { | |
33 | if (__builtin_expect (destlen < len, 0)) | |
34 | __chk_fail (); | |
35 | ||
36 | unsigned long int dstp = (long int) dest; | |
37 | unsigned long int srcp = (long int) src; | |
38 | ||
39 | /* This test makes the forward copying code be used whenever possible. | |
40 | Reduces the working set. */ | |
41 | if (dstp - srcp >= len) /* *Unsigned* compare! */ | |
42 | { | |
43 | /* Copy from the beginning to the end. */ | |
44 | ||
45 | /* If there not too few bytes to copy, use word copy. */ | |
46 | if (len >= OP_T_THRES) | |
47 | { | |
48 | /* Copy just a few bytes to make DSTP aligned. */ | |
49 | len -= (-dstp) % OPSIZ; | |
50 | BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ); | |
51 | ||
52 | /* Copy whole pages from SRCP to DSTP by virtual address | |
53 | manipulation, as much as possible. */ | |
54 | ||
55 | PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len); | |
56 | ||
57 | /* Copy from SRCP to DSTP taking advantage of the known | |
58 | alignment of DSTP. Number of bytes remaining is put | |
59 | in the third argument, i.e. in LEN. This number may | |
60 | vary from machine to machine. */ | |
61 | ||
62 | WORD_COPY_FWD (dstp, srcp, len, len); | |
63 | ||
64 | /* Fall out and copy the tail. */ | |
65 | } | |
66 | ||
67 | /* There are just a few bytes to copy. Use byte memory operations. */ | |
68 | BYTE_COPY_FWD (dstp, srcp, len); | |
69 | } | |
70 | else | |
71 | { | |
72 | /* Copy from the end to the beginning. */ | |
73 | srcp += len; | |
74 | dstp += len; | |
75 | ||
76 | /* If there not too few bytes to copy, use word copy. */ | |
77 | if (len >= OP_T_THRES) | |
78 | { | |
79 | /* Copy just a few bytes to make DSTP aligned. */ | |
80 | len -= dstp % OPSIZ; | |
81 | BYTE_COPY_BWD (dstp, srcp, dstp % OPSIZ); | |
82 | ||
83 | /* Copy from SRCP to DSTP taking advantage of the known | |
84 | alignment of DSTP. Number of bytes remaining is put | |
85 | in the third argument, i.e. in LEN. This number may | |
86 | vary from machine to machine. */ | |
87 | ||
88 | WORD_COPY_BWD (dstp, srcp, len, len); | |
89 | ||
90 | /* Fall out and copy the tail. */ | |
91 | } | |
92 | ||
93 | /* There are just a few bytes to copy. Use byte memory operations. */ | |
94 | BYTE_COPY_BWD (dstp, srcp, len); | |
95 | } | |
96 | ||
97 | return dest; | |
98 | } |