f6f38dd61e
memory regions are "potentially overlapping" to a test that determines that the regions are actually overlapping. Because the code for the overlapping case is seven instructions longer, this signifcantly improves performance in the average case.
106 lines
3.0 KiB
ArmAsm
106 lines
3.0 KiB
ArmAsm
/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from locore.s.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <machine/asm.h>
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#if defined(LIBC_SCCS)
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RCSID("$NetBSD: bcopy.S,v 1.6 1996/11/12 00:50:06 jtc Exp $")
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#endif
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/*
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* (ov)bcopy (src,dst,cnt)
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* ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
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*/
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#ifdef MEMCOPY
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ENTRY(memcpy)
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#else
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#ifdef MEMMOVE
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ENTRY(memmove)
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#else
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ENTRY(bcopy)
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#endif
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#endif
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pushl %esi
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pushl %edi
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#if defined(MEMCOPY) || defined(MEMMOVE)
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movl 12(%esp),%edi
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movl 16(%esp),%esi
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#else
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movl 12(%esp),%esi
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movl 16(%esp),%edi
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#endif
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movl 20(%esp),%ecx
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movl %edi,%eax
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subl %esi,%eax
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cmpl %ecx,%eax /* overlapping? */
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jb 1f
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cld /* nope, copy forwards. */
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shrl $2,%ecx /* copy by words */
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rep
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movsl
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movl 20(%esp),%ecx
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andl $3,%ecx /* any bytes left? */
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rep
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movsb
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#if defined(MEMCOPY) || defined(MEMMOVE)
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movl 12(%esp),%eax
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#endif
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popl %edi
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popl %esi
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ret
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1:
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addl %ecx,%edi /* copy backwards. */
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addl %ecx,%esi
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std
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andl $3,%ecx /* any fractional bytes? */
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decl %edi
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decl %esi
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rep
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movsb
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movl 20(%esp),%ecx /* copy remainder by words */
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shrl $2,%ecx
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subl $3,%esi
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subl $3,%edi
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rep
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movsl
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#if defined(MEMCOPY) || defined(MEMMOVE)
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movl 12(%esp),%eax
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#endif
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popl %edi
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popl %esi
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cld
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ret
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