/*
 * 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)