/*

 * 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.

 */

#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)