diff options
Diffstat (limited to 'missing_d/memmove.c')
| -rw-r--r-- | missing_d/memmove.c | 262 |
1 files changed, 126 insertions, 136 deletions
diff --git a/missing_d/memmove.c b/missing_d/memmove.c index 928b812e..a28a32d1 100644 --- a/missing_d/memmove.c +++ b/missing_d/memmove.c @@ -1,149 +1,139 @@ -/*- - * Copyright (c) 1990, 1993 - * The Regents of the University of California. All rights reserved. - * - * This code is derived from software contributed to Berkeley by - * Chris Torek. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - */ +/* 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). -#if 0 -#if defined(LIBC_SCCS) && !defined(lint) -static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93"; -#endif /* LIBC_SCCS and not lint */ + 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. -#include <sys/cdefs.h> -#include <string.h> -#endif + 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., 51 Franklin Street, Fifth Floor, + Boston, MA 02110-1301 USA */ /* - * sizeof(word) MUST BE A POWER OF TWO - * SO THAT wmask BELOW IS ALL ONES + * August 2006. For Gawk: Borrowed from GLIBC and hacked unmercifully. + * DON'T steal this for your own code, got straight to the GLIBC + * source for the original versions. */ -typedef int word; /* "word" used for optimal copy speed */ -#define wsize sizeof(word) -#define wmask (wsize - 1) -/* ADR: 1/2004. For gawk, we need memmove(). */ -#define MEMMOVE 1 +/* This stuff from libc/sysdeps/generic/memcopy.h */ +typedef unsigned char byte; + +/* Copy exactly NBYTES bytes from SRC_BP to DST_BP, + without any assumptions about alignment of the pointers. */ +#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \ + do \ + { \ + size_t __nbytes = (nbytes); \ + while (__nbytes > 0) \ + { \ + byte __x = ((byte *) src_bp)[0]; \ + src_bp += 1; \ + __nbytes -= 1; \ + ((byte *) dst_bp)[0] = __x; \ + dst_bp += 1; \ + } \ + } while (0) + +/* Copy exactly NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR, + beginning at the bytes right before the pointers and continuing towards + smaller addresses. Don't assume anything about alignment of the + pointers. */ +#define BYTE_COPY_BWD(dst_ep, src_ep, nbytes) \ + do \ + { \ + size_t __nbytes = (nbytes); \ + while (__nbytes > 0) \ + { \ + byte __x; \ + src_ep -= 1; \ + __x = ((byte *) src_ep)[0]; \ + dst_ep -= 1; \ + __nbytes -= 1; \ + ((byte *) dst_ep)[0] = __x; \ + } \ + } while (0) + +/* end of stuff from memcopy.h */ -/* - * Copy a block of memory, handling overlap. - * This is the routine that actually implements - * (the portable versions of) bcopy, memcpy, and memmove. - */ -#ifdef MEMCOPY -void * -memcpy(dst0, src0, length) -#else -#ifdef MEMMOVE void * -memmove(dst0, src0, length) -#else -void -bcopy(src0, dst0, length) -#endif -#endif - void *dst0; - const void *src0; - register size_t length; +memmove (dest, src, len) + void *dest; + const void *src; + size_t len; { - register char *dst = dst0; - register const char *src = src0; - register size_t t; - - if (length == 0 || dst == src) /* nothing to do */ - goto done; - - /* - * Macros: loop-t-times; and loop-t-times, t>0 - */ -#define TLOOP(s) if (t) TLOOP1(s) -#define TLOOP1(s) do { s; } while (--t) - - if ((unsigned long)dst < (unsigned long)src) { - /* - * Copy forward. - */ - t = (int)src; /* only need low bits */ - if ((t | (int)dst) & wmask) { - /* - * Try to align operands. This cannot be done - * unless the low bits match. - */ - if ((t ^ (int)dst) & wmask || length < wsize) - t = length; - else - t = wsize - (t & wmask); - length -= t; - TLOOP1(*dst++ = *src++); - } - /* - * Copy whole words, then mop up any trailing bytes. - */ - t = length / wsize; - TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); - t = length & wmask; - TLOOP(*dst++ = *src++); - } else { - /* - * Copy backwards. Otherwise essentially the same. - * Alignment works as before, except that it takes - * (t&wmask) bytes to align, not wsize-(t&wmask). - */ - src += length; - dst += length; - t = (int)src; - if ((t | (int)dst) & wmask) { - if ((t ^ (int)dst) & wmask || length <= wsize) - t = length; - else - t &= wmask; - length -= t; - TLOOP1(*--dst = *--src); - } - t = length / wsize; - TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src); - t = length & wmask; - TLOOP(*--dst = *--src); + 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 0 /* screw all this */ + /* 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. */ +#endif + BYTE_COPY_FWD (dstp, srcp, len); + } + else + { + /* Copy from the end to the beginning. */ + srcp += len; + dstp += len; + +#if 0 /* ditto */ + /* 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. */ } -done: -#if defined(MEMCOPY) || defined(MEMMOVE) - return (dst0); -#else - return; #endif + /* There are just a few bytes to copy. Use byte memory operations. */ + BYTE_COPY_BWD (dstp, srcp, len); + } + + return (dest); } -#undef wsize -#undef wmask -#undef MEMMOVE -#undef TLOOP -#undef TLOOP1 |