b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
160 lines
4.4 KiB
ArmAsm
160 lines
4.4 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. 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 1.4 2009/11/22 17:25:47 dsl 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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* Hacked about by dsl@netbsd.org
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*/
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#ifdef MEMCOPY
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ENTRY(memcpy)
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#define NO_OVERLAP
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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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movq %rdx,%rcx
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#if defined(MEMCOPY) || defined(MEMMOVE)
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movq %rdi,%rax /* must return destination address */
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mov %rdi,%r11 /* for misaligned check */
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#else
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mov %rsi,%r11 /* for misaligned check */
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xchgq %rdi,%rsi /* bcopy() has arg order reversed */
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#endif
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#if !defined(NO_OVERLAP)
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movq %rdi,%r8
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subq %rsi,%r8
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#endif
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shrq $3,%rcx /* count for copy by words */
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jz 8f /* j if less than 8 bytes */
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lea -8(%rdi,%rdx),%r9 /* target address of last 8 */
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mov -8(%rsi,%rdx),%r10 /* get last word */
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#if !defined(NO_OVERLAP)
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cmpq %rdx,%r8 /* overlapping? */
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jb 10f
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#endif
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/*
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* Non-overlaping, copy forwards.
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* Newer Intel cpus (Nehalem) will do 16byte read/write transfers
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* if %ecx is more than 76.
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* AMD might do something similar some day.
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*/
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and $7,%r11 /* destination misaligned ? */
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jnz 2f
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rep
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movsq
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mov %r10,(%r9) /* write last word */
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ret
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/*
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* Destination misaligned
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* AMD say it is better to align the destination (not the source).
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* This will also re-align copies if the source and dest are both
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* misaligned by the same amount)
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* (I think Nehalem will use its accelerated copy if the source
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* and destination have the same alignment.)
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*/
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2:
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lea -9(%r11,%rdx),%rcx /* post re-alignment count */
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neg %r11 /* now -1 .. -7 */
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mov (%rsi),%rdx /* get first word */
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mov %rdi,%r8 /* target for first word */
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lea 8(%rsi,%r11),%rsi
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lea 8(%rdi,%r11),%rdi
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shr $3,%rcx
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rep
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movsq
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mov %rdx,(%r8) /* write first word */
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mov %r10,(%r9) /* write last word */
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ret
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#if !defined(NO_OVERLAP)
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/* Must copy backwards.
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* Reverse copy is probably easy to code faster than 'rep movds'
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* since that requires (IIRC) an extra clock every 3 iterations (AMD).
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* However I don't suppose anything cares that much!
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* The big cost is the std/cld pair - reputedly 50+ cycles on Netburst P4.
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* The copy is aligned with the buffer start (more likely to
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* be a multiple of 8 than the end).
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*/
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10:
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lea -8(%rsi,%rcx,8),%rsi
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lea -8(%rdi,%rcx,8),%rdi
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std
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rep
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movsq
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cld
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mov %r10,(%r9) /* write last bytes */
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ret
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#endif
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/* Less than 8 bytes to copy, copy by bytes */
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/* Intel Nehalem optimise 'rep movsb' for <= 7 bytes (9-15 clocks).
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* For longer transfers it is 50+ !
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*/
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8: mov %rdx,%rcx
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#if !defined(NO_OVERLAP)
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cmpq %rdx,%r8 /* overlapping? */
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jb 81f
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#endif
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/* nope, copy forwards. */
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rep
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movsb
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ret
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#if !defined(NO_OVERLAP)
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/* Must copy backwards */
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81:
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lea -1(%rsi,%rcx),%rsi
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lea -1(%rdi,%rcx),%rdi
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std
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rep
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movsb
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cld
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ret
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#endif
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