minix/common/lib/libc/arch/vax/string/memcpy.S
Lionel Sambuc f14fb60209 Libraries updates and cleanup
* Updating common/lib
 * Updating lib/csu
 * Updating lib/libc
 * Updating libexec/ld.elf_so
 * Corrected test on __minix in featuretest to actually follow the
   meaning of the comment.
 * Cleaned up _REENTRANT-related defintions.
 * Disabled -D_REENTRANT for libfetch
 * Removing some unneeded __NBSD_LIBC defines and tests

Change-Id: Ic1394baef74d11b9f86b312f5ff4bbc3cbf72ce2
2013-01-14 11:36:26 +01:00

90 lines
3 KiB
ArmAsm

/* $NetBSD: memcpy.S,v 1.3 2011/01/25 04:45:28 matt Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* 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. 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.
*/
#include <machine/asm.h>
/* .asciz "@(#)memcpy.s 8.1 (Berkeley) 6/4/93" */
RCSID("$NetBSD: memcpy.S,v 1.3 2011/01/25 04:45:28 matt Exp $")
/*
* void *memcpy(dst, src, size)
* returns dst
*
* This optimises the usual case (count < 65536) at the expense
* of some extra memory references and branches when count >= 65536.
*/
ENTRY(memcpy, 0)
movzwl $65535,%r0 /* %r0 = 64K (needed below) */
movq 8(%ap),%r1 /* %r1 = src, %r2 = length */
movl 4(%ap),%r3 /* %r3 = dst */
cmpl %r1,%r3
bgtru 1f /* normal forward case */
beql 2f /* equal, nothing to do */
addl2 %r2,%r1 /* overlaps iff src<dst but src+len>dst */
cmpl %r1,%r3
bgtru 4f /* overlapping, must move backwards */
subl2 %r2,%r1
1: /* move forward */
cmpl %r2,%r0
bgtru 3f /* stupid movc3 limitation */
movc3 %r2,(%r1),(%r3) /* move it all */
2:
movl 4(%ap),%r0 /* return original dst */
ret
3:
subl2 %r0,12(%ap) /* adjust length by 64K */
movc3 %r0,(%r1),(%r3) /* move 64K */
movl 12(%ap),%r2
decw %r0 /* from 0 to 65535 */
brb 1b /* retry */
4: /* move backward */
addl2 %r2,%r3
5:
cmpl %r2,%r0
bgtru 6f /* stupid movc3 limitation */
subl2 %r2,%r1
subl2 %r2,%r3
movc3 %r2,(%r1),(%r3) /* move it all */
movl 4(%ap),%r0 /* return original dst */
ret
6:
subl2 %r0,12(%ap) /* adjust length by 64K */
subl2 %r0,%r1
subl2 %r0,%r3
movc3 %r0,(%r1),(%r3) /* move 64K */
movl 12(%ap),%r2
decw %r0
subl2 %r0,%r1
subl2 %r0,%r3
brb 5b
END(memcpy)