about summary refs log tree commit diff
path: root/REORG.TODO/string/memmove.c
diff options
context:
space:
mode:
authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/string/memmove.c
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
downloadglibc-zack/build-layout-experiment.tar.gz
glibc-zack/build-layout-experiment.tar.xz
glibc-zack/build-layout-experiment.zip
Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/string/memmove.c')
-rw-r--r--REORG.TODO/string/memmove.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/REORG.TODO/string/memmove.c b/REORG.TODO/string/memmove.c
new file mode 100644
index 0000000000..d8c2116b01
--- /dev/null
+++ b/REORG.TODO/string/memmove.c
@@ -0,0 +1,115 @@
+/* Copy memory to memory until the specified number of bytes
+   has been copied.  Overlap is handled correctly.
+   Copyright (C) 1991-2017 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
+   <http://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