1 | /* Macros for copying by pages; used in memcpy, memmove. |
2 | Copyright (C) 1995-2021 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | /* The macro PAGE_COPY_FWD_MAYBE defined in memcopy.h is used in memmove if the |
20 | PAGE_COPY_THRESHOLD macro is set to a non-zero value. The default is 0, |
21 | that is copying by pages is not implemented. |
22 | |
23 | System-specific pagecopy.h files that want to support page copying should |
24 | define these macros: |
25 | |
26 | PAGE_COPY_THRESHOLD |
27 | -- A non-zero minimum size for which virtual copying by pages is worthwhile. |
28 | |
29 | PAGE_SIZE |
30 | -- Size of a page. |
31 | |
32 | PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes) |
33 | -- Macro to perform the virtual copy operation. |
34 | The pointers will be aligned to PAGE_SIZE bytes. |
35 | */ |
36 | |
37 | #define PAGE_COPY_THRESHOLD 0 |
38 | |