mirror of
git://sourceware.org/git/glibc.git
synced 2025-01-06 12:00:24 +08:00
30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
116 lines
4.0 KiB
C
116 lines
4.0 KiB
C
/* memcopy.h -- definitions for memory copy functions. Generic C version.
|
|
Copyright (C) 1991-2021 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
/* The strategy of the memory functions is:
|
|
|
|
1. Copy bytes until the destination pointer is aligned.
|
|
|
|
2. Copy words in unrolled loops. If the source and destination
|
|
are not aligned in the same way, use word memory operations,
|
|
but shift and merge two read words before writing.
|
|
|
|
3. Copy the few remaining bytes.
|
|
|
|
This is fast on processors that have at least 10 registers for
|
|
allocation by GCC, and that can access memory at reg+const in one
|
|
instruction.
|
|
|
|
I made an "exhaustive" test of this memmove when I wrote it,
|
|
exhaustive in the sense that I tried all alignment and length
|
|
combinations, with and without overlap. */
|
|
|
|
#include <sysdeps/generic/memcopy.h>
|
|
|
|
/* The macros defined in this file are:
|
|
|
|
BYTE_COPY_FWD(dst_beg_ptr, src_beg_ptr, nbytes_to_copy)
|
|
|
|
BYTE_COPY_BWD(dst_end_ptr, src_end_ptr, nbytes_to_copy)
|
|
|
|
WORD_COPY_FWD(dst_beg_ptr, src_beg_ptr, nbytes_remaining, nbytes_to_copy)
|
|
|
|
WORD_COPY_BWD(dst_end_ptr, src_end_ptr, nbytes_remaining, nbytes_to_copy)
|
|
|
|
MERGE(old_word, sh_1, new_word, sh_2)
|
|
[I fail to understand. I feel stupid. --roland]
|
|
*/
|
|
|
|
|
|
/* Threshold value for when to enter the unrolled loops. */
|
|
#undef OP_T_THRES
|
|
#define OP_T_THRES 16
|
|
|
|
/* Copy exactly NBYTES bytes from SRC_BP to DST_BP,
|
|
without any assumptions about alignment of the pointers. */
|
|
#undef BYTE_COPY_FWD
|
|
#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \
|
|
do \
|
|
{ \
|
|
size_t __nbytes = (nbytes); \
|
|
if (__nbytes & 1) \
|
|
{ \
|
|
((byte *) dst_bp)[0] = ((byte *) src_bp)[0]; \
|
|
src_bp += 1; \
|
|
dst_bp += 1; \
|
|
__nbytes -= 1; \
|
|
} \
|
|
while (__nbytes > 0) \
|
|
{ \
|
|
byte __x = ((byte *) src_bp)[0]; \
|
|
byte __y = ((byte *) src_bp)[1]; \
|
|
src_bp += 2; \
|
|
__nbytes -= 2; \
|
|
((byte *) dst_bp)[0] = __x; \
|
|
((byte *) dst_bp)[1] = __y; \
|
|
dst_bp += 2; \
|
|
} \
|
|
} while (0)
|
|
|
|
/* Copy exactly NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR,
|
|
beginning at the bytes right before the pointers and continuing towards
|
|
smaller addresses. Don't assume anything about alignment of the
|
|
pointers. */
|
|
#undef BYTE_COPY_BWD
|
|
#define BYTE_COPY_BWD(dst_ep, src_ep, nbytes) \
|
|
do \
|
|
{ \
|
|
size_t __nbytes = (nbytes); \
|
|
if (__nbytes & 1) \
|
|
{ \
|
|
src_ep -= 1; \
|
|
dst_ep -= 1; \
|
|
((byte *) dst_ep)[0] = ((byte *) src_ep)[0]; \
|
|
__nbytes -= 1; \
|
|
} \
|
|
while (__nbytes > 0) \
|
|
{ \
|
|
byte __x, __y; \
|
|
src_ep -= 2; \
|
|
__y = ((byte *) src_ep)[1]; \
|
|
__x = ((byte *) src_ep)[0]; \
|
|
dst_ep -= 2; \
|
|
__nbytes -= 2; \
|
|
((byte *) dst_ep)[1] = __y; \
|
|
((byte *) dst_ep)[0] = __x; \
|
|
} \
|
|
} while (0)
|
|
|
|
/* The powerpc memcpy implementation is safe to use for memmove. */
|
|
#undef MEMCPY_OK_FOR_FWD_MEMMOVE
|
|
#define MEMCPY_OK_FOR_FWD_MEMMOVE 1
|