From 28f540f45bbacd939bfd07f213bcad2bf730b1bf Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 18 Feb 1995 01:27:10 +0000 Subject: initial import --- sysdeps/generic/memmove.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 sysdeps/generic/memmove.c (limited to 'sysdeps/generic/memmove.c') diff --git a/sysdeps/generic/memmove.c b/sysdeps/generic/memmove.c new file mode 100644 index 0000000000..e3016819d9 --- /dev/null +++ b/sysdeps/generic/memmove.c @@ -0,0 +1,99 @@ +/* memmove -- copy memory to memory until the specified number of bytes + has been copied. Overlap is handled correctly. + Copyright (C) 1991 Free Software Foundation, Inc. + 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include +#include +#include + +/* 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 +#endif +#if !defined(RETURN) || !defined(rettype) +#define RETURN(s) return (s) /* Return DEST. */ +#define rettype PTR +#endif + +rettype +DEFUN(memmove, (a1, a2, len), + a1const PTR a1 AND a2const PTR a2 AND 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 from SRCP to DSTP taking advantage of the known + alignment of DSTP. Number of bytes remaining is put + in the third argumnet, 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 argumnet, 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); +} -- cgit 1.4.1