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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 "__align_cpy_8.s"
/* __align_cpy_8(s1, s2, n)
*
* Copy 8-byte aligned source to 8-byte aligned target in multiples of 8 bytes.
*
* Input:
* o0 address of target
* o1 address of source
* o2 number of bytes to copy (must be a multiple of 8)
* Output:
* o0 address of target
* Caller's registers that have been changed by this function:
* o1-o5
*
* Note:
* This helper routine will not be used by any 32-bit compilations. To do
* so would break binary compatibility with previous versions of Solaris.
*
* Assumptions:
* Source and target addresses are 8-byte aligned.
* Bytes to be copied are non-overlapping or _exactly_ overlapping.
* The number of bytes to be copied is a multiple of 8.
* Call will _usually_ be made with a byte count of more than 4*8 and
* less than a few hundred bytes. Legal values are 0 to MAX_SIZE_T.
*
* Optimization attempt:
* Reasonable speed for a generic v9. Going for 32 bytes at a time
* rather than 16 bytes at a time did not result in a time saving for
* the number of bytes expected to be copied. No timing runs using other
* levels of optimization have been tried yet.
*
* Even when multiples of 16 bytes were used, the savings by going for 32 bytes
* at a time were about 2%. Thus, __align_cpy_16 is a second entry point to
* the same code as __align_cpy_8.
*
* Register usage:
* o1 source address (updated for each read)
* o2 byte count remaining
* o3 contents being copied
* o4 more contents being copied
* o5 target address
*/
#include <sys/asm_linkage.h>
ENTRY(__align_cpy_8)
ENTRY(__align_cpy_16)
cmp %o0, %o1 ! Identical--do nothing.
be,pn %xcc, .done
subcc %o2, 8, %o2
bz,pn %xcc, .wrdbl2 ! Only 8 bytes need to be copied.
mov %o0, %o5 ! Original target address is returned.
bpos,a,pt %xcc, .wrdbl1 ! Have at least 16 bytes to copy.
ldx [%o1], %o3
.done:
retl ! No bytes to copy.
nop
.align 32
.wrdbl1: ! Copy 16 bytes at a time.
subcc %o2, 16, %o2
ldx [%o1+8], %o4
add %o1, 16, %o1
stx %o3, [%o5]
stx %o4, [%o5+8]
add %o5, 16, %o5
bg,a,pt %xcc, .wrdbl1 ! Have at least 16 more bytes.
ldx [%o1], %o3
bz,a,pt %xcc, .wrdbl3 ! Have 8 bytes remaining to copy.
ldx [%o1], %o3
retl
nop
.wrdbl2:
ldx [%o1], %o3 ! Copy last 8 bytes.
.wrdbl3:
stx %o3, [%o5]
retl
nop
SET_SIZE(__align_cpy_8)
SET_SIZE(__align_cpy_16)
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