mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-03 04:01:43 +08:00
59 lines
2.1 KiB
ArmAsm
59 lines
2.1 KiB
ArmAsm
/* memcpy - copy a block from source to destination. S/390 version.
|
|
Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* INPUT PARAMETERS
|
|
%r2 = address of destination memory area
|
|
%r3 = address of source memory area
|
|
%r4 = number of bytes to copy. */
|
|
|
|
#include "sysdep.h"
|
|
#include "asm-syntax.h"
|
|
|
|
.text
|
|
ENTRY(memcpy)
|
|
ltr %r4,%r4
|
|
jz .L3
|
|
ahi %r4,-1 # length - 1
|
|
lr %r1,%r2 # copy destination address
|
|
lr %r5,%r4
|
|
srl %r5,8
|
|
ltr %r5,%r5 # < 256 bytes to move ?
|
|
jz .L1
|
|
chi %r5,255 # > 1MB to move ?
|
|
jh .L4
|
|
.L0: mvc 0(256,%r1),0(%r3) # move in 256 byte chunks
|
|
la %r1,256(%r1)
|
|
la %r3,256(%r3)
|
|
brct %r5,.L0
|
|
.L1: bras %r5,.L2 # setup base pointer for execute
|
|
mvc 0(1,%r1),0(%r3) # instruction for execute
|
|
.L2: ex %r4,0(%r5) # execute mvc with length ((%r4)&255)+1
|
|
.L3: br %r14
|
|
# data copies > 1MB are faster with mvcle.
|
|
.L4: ahi %r4,1 # length + 1
|
|
lr %r5,%r4 # source length
|
|
lr %r4,%r3 # source address
|
|
lr %r3,%r5 # destination length = source length
|
|
.L5: mvcle %r2,%r4,0 # thats it, MVCLE is your friend
|
|
jo .L5
|
|
lr %r2,%r1 # return destination address
|
|
br %r14
|
|
END(memcpy)
|
|
libc_hidden_builtin_def (memcpy)
|