/*
 * 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	"__align_cpy_2.s"

/*
 * __align_cpy_2(s1, s2, len)
 *
 * Copy s2 to s1, always copy n bytes.
 * Note: this does not work for overlapped copies, bcopy() does
 *	 This routine is copied from memcpy.s, with all values doubled.
 *	 No attempt has been made to improve the comments or performance.
 *
 */

#include <sys/asm_linkage.h>

	ENTRY(__align_cpy_2)
	cmp	%o0, %o1
	be,pn	%xcc, .done		! Identical addresses--done.
	mov	%o0, %g5		! save des address for return val
	cmp	%o2, 18			! for small counts copy bytes
	ble,pn	%xcc, .dbytecp
	andcc	%o1, 6, %o5		! is src 8-byte aligned
	bz,pn	%xcc, .aldst
	cmp	%o5, 4			! is src 4-byte aligned
	be,pt	%xcc, .s2algn
	cmp	%o5, 6			! src is 2-byte aligned
.s1algn:lduh	[%o1], %o3		! move 2 or 6 bytes to align it
	inc	2, %o1
	sth	%o3, [%g5]		! move 2 bytes to align src
	inc	2, %g5
	bne,pt	%xcc, .s2algn
	dec	2, %o2
	b	.ald			! now go align dest
	andcc	%g5, 6, %o5

.s2algn:lduw	[%o1], %o3		! know src is 4-byte aligned
	inc	4, %o1
	srlx	%o3, 16, %o4
	sth	%o4, [%g5]		! have to do 2-bytes,
	sth	%o3, [%g5 + 2]		! don't know dst alignment
	inc	4, %g5
	dec	4, %o2

.aldst:	andcc	%g5, 6, %o5		! align the destination address
.ald:	bz,pn	%xcc, .w4cp
	cmp	%o5, 4
	bz,pn	%xcc, .w2cp
	cmp	%o5, 6
.w3cp:	ldx	[%o1], %o4
	inc	8, %o1
	srlx	%o4, 48, %o5
	sth	%o5, [%g5]
	bne,pt	%xcc, .w1cp
	inc	2, %g5
	dec	2, %o2
	andn	%o2, 6, %o3		! o3 is aligned word count
	sub	%o1, %g5, %o1		! g5 gets the difference

1:	sllx	%o4, 16, %g1		! save residual bytes
	ldx	[%o1+%g5], %o4
	deccc	8, %o3
	srlx	%o4, 48, %o5		! merge with residual
	or	%o5, %g1, %g1
	stx	%g1, [%g5]
	bnz,pt	%xcc, 1b
	inc	8, %g5
	sub	%o1, 6, %o1		! used two bytes of last word read
	b	7f
	and	%o2, 6, %o2

.w1cp:	srlx	%o4, 16, %o5
	st	%o5, [%g5]
	inc	4, %g5
	dec	6, %o2
	andn	%o2, 6, %o3
	sub	%o1, %g5, %o1		! g5 gets the difference

2:	sllx	%o4, 48, %g1		! save residual bytes
	ldx	[%o1+%g5], %o4
	deccc	8, %o3
	srlx	%o4, 16, %o5		! merge with residual
	or	%o5, %g1, %g1
	stx	%g1, [%g5]
	bnz,pt	%xcc, 2b
	inc	8, %g5
	sub	%o1, 2, %o1		! used six bytes of last word read
	b	7f
	and	%o2, 6, %o2

.w2cp:	ldx	[%o1], %o4
	inc	8, %o1
	srlx	%o4, 32, %o5
	st	%o5, [%g5]
	inc	4, %g5
	dec	4, %o2
	andn	%o2, 6, %o3		! o3 is aligned word count
	sub	%o1, %g5, %o1		! g5 gets the difference
	
3:	sllx	%o4, 32, %g1		! save residual bytes
	ldx	[%o1+%g5], %o4
	deccc	8, %o3
	srlx	%o4, 32, %o5		! merge with residual
	or	%o5, %g1, %g1
	stx	%g1, [%g5]
	bnz,pt	%xcc, 3b
	inc	8, %g5
	sub	%o1, 4, %o1		! used four bytes of last word read
	b	7f
	and	%o2, 6, %o2

.w4cp:	andn	%o2, 6, %o3		! o3 is aligned word count
	sub	%o1, %g5, %o1		! g5 gets the difference

1:	ldx	[%o1+%g5], %o4		! read from address
	deccc	8, %o3			! decrement count
	stx	%o4, [%g5]		! write at destination address
	bg,pt	%xcc, 1b
	inc	8, %g5			! increment to address
	b	7f
	and	%o2, 6, %o2		! number of leftover bytes, if any

	!
	! differenced byte copy, works with any alignment
	!
.dbytecp:
	b	7f
	sub	%o1, %g5, %o1		! g5 gets the difference

4:	sth	%o4, [%g5]		! write to address
	inc	2, %g5			! inc to address
7:	deccc	2, %o2			! decrement count
	bge,a,pt %xcc,4b		! loop till done
	lduh	[%o1+%g5], %o4		! read from address
.done:
	retl
	nop

	SET_SIZE(__align_cpy_2)