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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 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
.file "memmove.s"
#include <sys/asm_linkage.h>
ANSI_PRAGMA_WEAK(memmove,function)
/*
* memmove(s1, s2, len)
* Copy s2 to s1, always copy n bytes.
* For overlapped copies it does the right thing.
*/
ENTRY(memmove)
save %sp, -SA(MINFRAME), %sp ! not a leaf routine any more
mov %i0, %l6 ! Save pointer to destination
cmp %i1, %i0 ! if from address is >= to use forward copy
bgeu,a 2f ! else use backward if ...
cmp %i2, 17 ! delay slot, for small counts copy bytes
sub %i0, %i1, %i4 ! get difference of two addresses
cmp %i2, %i4 ! compare size and difference of addresses
bgu ovbc ! if size is bigger, have do overlapped copy
cmp %i2, 17 ! delay slot, for small counts copy bytes
!
! normal, copy forwards
!
2: ble dbytecp
andcc %i1, 3, %i5 ! is src word aligned
bz aldst
cmp %i5, 2 ! is src half-word aligned
be s2algn
cmp %i5, 3 ! src is byte aligned
s1algn: ldub [%i1], %i3 ! move 1 or 3 bytes to align it
inc 1, %i1
stb %i3, [%i0] ! move a byte to align src
inc 1, %i0
bne s2algn
dec %i2
b ald ! now go align dest
andcc %i0, 3, %i5
s2algn: lduh [%i1], %i3 ! know src is 2 byte alinged
inc 2, %i1
srl %i3, 8, %i4
stb %i4, [%i0] ! have to do bytes,
stb %i3, [%i0 + 1] ! don't know dst alingment
inc 2, %i0
dec 2, %i2
aldst: andcc %i0, 3, %i5 ! align the destination address
ald: bz w4cp
cmp %i5, 2
bz w2cp
cmp %i5, 3
w3cp: ld [%i1], %i4
inc 4, %i1
srl %i4, 24, %i5
stb %i5, [%i0]
bne w1cp
inc %i0
dec 1, %i2
andn %i2, 3, %i3 ! i3 is aligned word count
dec 4, %i3 ! avoid reading beyond tail of src
sub %i1, %i0, %i1 ! i1 gets the difference
1: sll %i4, 8, %g1 ! save residual bytes
ld [%i1+%i0], %i4
deccc 4, %i3
srl %i4, 24, %i5 ! merge with residual
or %i5, %g1, %g1
st %g1, [%i0]
bnz 1b
inc 4, %i0
sub %i1, 3, %i1 ! used one byte of last word read
and %i2, 3, %i2
b 7f
inc 4, %i2
w1cp: srl %i4, 8, %i5
sth %i5, [%i0]
inc 2, %i0
dec 3, %i2
andn %i2, 3, %i3
dec 4, %i3 ! avoid reading beyond tail of src
sub %i1, %i0, %i1 ! i1 gets the difference
2: sll %i4, 24, %g1 ! save residual bytes
ld [%i1+%i0], %i4
deccc 4, %i3
srl %i4, 8, %i5 ! merge with residual
or %i5, %g1, %g1
st %g1, [%i0]
bnz 2b
inc 4, %i0
sub %i1, 1, %i1 ! used three bytes of last word read
and %i2, 3, %i2
b 7f
inc 4, %i2
w2cp: ld [%i1], %i4
inc 4, %i1
srl %i4, 16, %i5
sth %i5, [%i0]
inc 2, %i0
dec 2, %i2
andn %i2, 3, %i3 ! i3 is aligned word count
dec 4, %i3 ! avoid reading beyond tail of src
sub %i1, %i0, %i1 ! i1 gets the difference
3: sll %i4, 16, %g1 ! save residual bytes
ld [%i1+%i0], %i4
deccc 4, %i3
srl %i4, 16, %i5 ! merge with residual
or %i5, %g1, %g1
st %g1, [%i0]
bnz 3b
inc 4, %i0
sub %i1, 2, %i1 ! used two bytes of last word read
and %i2, 3, %i2
b 7f
inc 4, %i2
w4cp: andn %i2, 3, %i3 ! i3 is aligned word count
sub %i1, %i0, %i1 ! i1 gets the difference
1: ld [%i1+%i0], %i4 ! read from address
deccc 4, %i3 ! decrement count
st %i4, [%i0] ! write at destination address
bg 1b
inc 4, %i0 ! increment to address
b 7f
and %i2, 3, %i2 ! number of leftover bytes, if any
!
! differenced byte copy, works with any alignment
!
dbytecp:
b 7f
sub %i1, %i0, %i1 ! i1 gets the difference
4: stb %i4, [%i0] ! write to address
inc %i0 ! inc to address
7: deccc %i2 ! decrement count
bge,a 4b ! loop till done
ldub [%i1+%i0], %i4 ! read from address
ret
restore %l6, %g0, %o0 ! return pointer to destination
!
! an overlapped copy that must be done "backwards"
!
ovbc: add %i1, %i2, %i1 ! get to end of source space
add %i0, %i2, %i0 ! get to end of destination space
sub %i1, %i0, %i1 ! i1 gets the difference
5: dec %i0 ! decrement to address
ldub [%i1+%i0], %i3 ! read a byte
deccc %i2 ! decrement count
bg 5b ! loop until done
stb %i3, [%i0] ! write byte
ret
restore %l6, %g0, %o0 ! return pointer to destination
SET_SIZE(memmove)
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