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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
.file "memcpy.s"
#include <sys/asm_linkage.h>
ANSI_PRAGMA_WEAK(memmove,function)
ANSI_PRAGMA_WEAK(memcpy,function)
#include "SYS.h"
ENTRY(memcpy)
movl %edi,%edx / save register variables
pushl %esi
movl 8(%esp),%edi / %edi = dest address
movl 12(%esp),%esi / %esi = source address
movl 16(%esp),%ecx / %ecx = length of string
movl %edi,%eax / return value from the call
shrl $2,%ecx / %ecx = number of words to move
rep ; smovl / move the words
movl 16(%esp),%ecx / %ecx = number of bytes to move
andl $0x3,%ecx / %ecx = number of bytes left to move
rep ; smovb / move the bytes
popl %esi / restore register variables
movl %edx,%edi
ret
SET_SIZE(memcpy)
ENTRY(memmove)
pushl %edi / save off %edi, %esi and move destination
movl 4+12(%esp),%ecx / get number of bytes to move
pushl %esi
testl %ecx,%ecx / if (n == 0)
je .CleanupReturn / return(s);
movl 8+ 4(%esp),%edi / destination buffer address
movl 8+ 8(%esp),%esi / source buffer address
.Common:
movl $3,%eax / heavily used constant
cmpl %esi,%edi / if (source addr > dest addr)
leal -1(%esi,%ecx),%edx
jbe .CopyRight /
cmpl %edx,%edi
jbe .CopyLeft
.CopyRight:
cmpl $8,%ecx / if (size < 8 bytes)
jbe .OneByteCopy / goto fast short copy loop
.FourByteCopy:
movl %ecx,%edx / save count
movl %esi,%ecx / get source buffer 4 byte aligned
andl %eax,%ecx
jz .SkipAlignRight
subl %ecx,%edx
rep; smovb / do the byte part of copy
.SkipAlignRight:
movl %edx,%ecx
shrl $2,%ecx
rep; smovl / do the long word part
movl %edx,%ecx / compute bytes left to move
andl %eax,%ecx / complete copy of remaining bytes
jz .CleanupReturn
.OneByteCopy:
rep; smovb / do the byte part of copy
.CleanupReturn:
popl %esi / }
popl %edi / restore registers
movl 4(%esp),%eax / set up return value
.Return:
ret / return(dba);
.CopyLeft:
std / reverse direction bit (RtoL)
cmpl $12,%ecx / if (size < 12)
ja .BigCopyLeft / {
movl %edx,%esi / src = src + size - 1
leal -1(%ecx,%edi),%edi / dst = dst + size - 1
rep; smovb / do the byte copy
cld / reset direction flag to LtoR
popl %esi / }
popl %edi / restore registers
movl 4(%esp),%eax / set up return value
ret / return(dba);
.BigCopyLeft: / } else {
xchgl %edx,%ecx
movl %ecx,%esi / align source w/byte copy
leal -1(%edx,%edi),%edi
andl %eax,%ecx
jz .SkipAlignLeft
addl $1, %ecx / we need to insure that future
subl %ecx,%edx / copy is done on aligned boundary
rep; smovb
.SkipAlignLeft:
movl %edx,%ecx
subl %eax,%esi
shrl $2,%ecx / do 4 byte copy RtoL
subl %eax,%edi
rep; smovl
andl %eax,%edx / do 1 byte copy whats left
jz .CleanupReturnLeft
movl %edx,%ecx
addl %eax,%esi / rep; smovl instruction will decrement
addl %eax,%edi / %edi, %esi by four after each copy
/ adding 3 will restore pointers to byte
/ before last double word copied
/ which is where they are expected to
/ be for the single byte copy code
rep; smovb
.CleanupReturnLeft:
cld / reset direction flag to LtoR
popl %esi
popl %edi / restore registers
movl 4(%esp),%eax / set up return value
ret / return(dba);
SET_SIZE(memmove)
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