/* Copy memory to memory until the specified number of bytes

   has been copied.  Overlap is handled correctly.

   Copyright (C) 1991-2018 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