142 lines
4.8 KiB
ArmAsm
142 lines
4.8 KiB
ArmAsm
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/* $NetBSD: bzero.S,v 1.2 2008/04/28 20:22:52 martin Exp $ */
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/*-
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* Copyright (c) 1997 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by J.T. Conklin.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*-
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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 software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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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. 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) && !defined(lint)
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#if 0
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RCSID("from: @(#)bzero.s 5.1 (Berkeley) 5/12/90")
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#else
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RCSID("$NetBSD: bzero.S,v 1.2 2008/04/28 20:22:52 martin Exp $")
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#endif
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#endif /* LIBC_SCCS and not lint */
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ENTRY(bzero)
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movl %d2,%sp@-
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movl %sp@(8),%a0 | destination
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movl %sp@(12),%d1 | count
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movql #0,%d2
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/*
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* It isn't worth the overhead of aligning to {long}word boundries
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* if the string is too short.
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*/
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cmpl #8,%d1
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jlt Lbzbyte
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/* word align */
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movl %a0,%d0
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btst #0,%d0 | if (dst & 1)
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jeq Lbzalgndw |
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movb %d2,%a0@+ | *(char *)dst++ = 0
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subql #1,%d1 | len--
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Lbzalgndw:
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/* long word align */
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btst #1,%d0 | if (dst & 2)
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jeq Lbzalgndl |
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movw %d2,%a0@+ | *(short *)dst++ = 0
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subql #2,%d1 | len -= 2
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Lbzalgndl:
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/* zero by 8 longwords */
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movel %d1,%d0
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lsrl #5,%d0 | cnt = len / 32
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jeq Lbzlong | if (cnt)
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andl #31,%d1 | len %= 32
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subql #1,%d0 | set up for dbf
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Lbz32loop:
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movl %d2,%a0@+ | zero 8 long words
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movl %d2,%a0@+
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movl %d2,%a0@+
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movl %d2,%a0@+
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movl %d2,%a0@+
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movl %d2,%a0@+
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movl %d2,%a0@+
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movl %d2,%a0@+
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dbf %d0,Lbz32loop | till done
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clrw %d0
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subql #1,%d0
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jcc Lbz32loop
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Lbzlong:
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/* copy by longwords */
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movel %d1,%d0
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lsrl #2,%d0 | cnt = len / 4
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jeq Lbzbyte | if (cnt)
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subql #1,%d0 | set up for dbf
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Lbzlloop:
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movl %d2,%a0@+ | clear longwords
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dbf %d0,Lbzlloop | till done
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andl #3,%d1 | len %= 4
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jeq Lbzdone
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subql #1,%d1 | set up for dbf
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Lbzbloop:
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movb %d2,%a0@+ | zero bytes
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Lbzbyte:
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dbf %d1,Lbzbloop | till done
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Lbzdone:
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movl %sp@+,%d2
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rts
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