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Diffstat (limited to 'sysdeps/generic/memmove.c')
-rw-r--r--sysdeps/generic/memmove.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/sysdeps/generic/memmove.c b/sysdeps/generic/memmove.c
new file mode 100644
index 0000000000..16671f7bb5
--- /dev/null
+++ b/sysdeps/generic/memmove.c
@@ -0,0 +1,112 @@
+/* Copy memory to memory until the specified number of bytes
+ has been copied. Overlap is handled correctly.
+ Copyright (C) 1991, 1995, 1996, 1997, 2003 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <string.h>
+#include <memcopy.h>
+#include <pagecopy.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
+
+
+rettype
+memmove (a1, a2, len)
+ 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 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);
+ }
+ 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