mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 00:31:08 +00:00
116 lines
3.5 KiB
C
116 lines
3.5 KiB
C
/* Copy memory to memory until the specified number of bytes
|
|
has been copied. Overlap is handled correctly.
|
|
Copyright (C) 1991-2020 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Torbjorn Granlund (tege@sics.se).
|
|
|
|
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/>. */
|
|
|
|
#include <string.h>
|
|
#include <memcopy.h>
|
|
|
|
/* All this is so that bcopy.c can #include
|
|
this file after defining some things. */
|
|
#ifndef a1
|
|
#define a1 dest /* First arg is DEST. */
|
|
#define a1const
|
|
#define a2 src /* Second arg is SRC. */
|
|
#define a2const const
|
|
#undef memmove
|
|
#endif
|
|
#if !defined(RETURN) || !defined(rettype)
|
|
#define RETURN(s) return (s) /* Return DEST. */
|
|
#define rettype void *
|
|
#endif
|
|
|
|
#ifndef MEMMOVE
|
|
#define MEMMOVE memmove
|
|
#endif
|
|
|
|
rettype
|
|
inhibit_loop_to_libcall
|
|
MEMMOVE (a1const void *a1, a2const void *a2, size_t len)
|
|
{
|
|
unsigned long int dstp = (long int) dest;
|
|
unsigned long int srcp = (long int) src;
|
|
|
|
/* This test makes the forward copying code be used whenever possible.
|
|
Reduces the working set. */
|
|
if (dstp - srcp >= len) /* *Unsigned* compare! */
|
|
{
|
|
/* Copy from the beginning to the end. */
|
|
|
|
#if MEMCPY_OK_FOR_FWD_MEMMOVE
|
|
dest = memcpy (dest, src, len);
|
|
#else
|
|
/* If there not too few bytes to copy, use word copy. */
|
|
if (len >= OP_T_THRES)
|
|
{
|
|
/* Copy just a few bytes to make DSTP aligned. */
|
|
len -= (-dstp) % OPSIZ;
|
|
BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
|
|
|
|
/* Copy whole pages from SRCP to DSTP by virtual address
|
|
manipulation, as much as possible. */
|
|
|
|
PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
|
|
|
|
/* Copy from SRCP to DSTP taking advantage of the known
|
|
alignment of DSTP. Number of bytes remaining is put
|
|
in the third argument, i.e. in LEN. This number may
|
|
vary from machine to machine. */
|
|
|
|
WORD_COPY_FWD (dstp, srcp, len, len);
|
|
|
|
/* Fall out and copy the tail. */
|
|
}
|
|
|
|
/* There are just a few bytes to copy. Use byte memory operations. */
|
|
BYTE_COPY_FWD (dstp, srcp, len);
|
|
#endif /* MEMCPY_OK_FOR_FWD_MEMMOVE */
|
|
}
|
|
else
|
|
{
|
|
/* Copy from the end to the beginning. */
|
|
srcp += len;
|
|
dstp += len;
|
|
|
|
/* If there not too few bytes to copy, use word copy. */
|
|
if (len >= OP_T_THRES)
|
|
{
|
|
/* Copy just a few bytes to make DSTP aligned. */
|
|
len -= dstp % OPSIZ;
|
|
BYTE_COPY_BWD (dstp, srcp, dstp % OPSIZ);
|
|
|
|
/* Copy from SRCP to DSTP taking advantage of the known
|
|
alignment of DSTP. Number of bytes remaining is put
|
|
in the third argument, i.e. in LEN. This number may
|
|
vary from machine to machine. */
|
|
|
|
WORD_COPY_BWD (dstp, srcp, len, len);
|
|
|
|
/* Fall out and copy the tail. */
|
|
}
|
|
|
|
/* There are just a few bytes to copy. Use byte memory operations. */
|
|
BYTE_COPY_BWD (dstp, srcp, len);
|
|
}
|
|
|
|
RETURN (dest);
|
|
}
|
|
#ifndef memmove
|
|
libc_hidden_builtin_def (memmove)
|
|
#endif
|