/* bcopy -- copy a block from source to destination. 64 bit S/390 version.
This file is part of the GNU C Library.
Copyright (C) 2000-2018 Free Software Foundation, Inc.
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 source
%r3 = address of destination
%r4 = number of bytes to copy. */
#include "sysdep.h"
#include "asm-syntax.h"
.text
ENTRY(__bcopy)
ltgr %r1,%r4 # zero bcopy ?
jz .L4
clgr %r2,%r3 # check against destructive overlap
jnl .L0
algr %r1,%r2
clgr %r1,%r3
jh .L7
.L0: aghi %r4,-1 # length - 1
srlg %r1,%r4,8
ltgr %r1,%r1 # < 256 bytes to move ?
jz .L2
cghi %r1,255 # > 1MB to move ?
jh .L5
.L1: mvc 0(256,%r3),0(%r2) # move in 256 byte chunks
la %r2,256(%r2)
la %r3,256(%r3)
brctg %r1,.L1
.L2: bras %r1,.L3 # setup base pointer for execute
mvc 0(1,%r3),0(%r2) # instruction for execute
.L3: ex %r4,0(%r1) # execute mvc with length ((%r4)&255)+1
.L4: br %r14
# data copies > 1MB are faster with mvcle.
.L5: aghi %r4,1 # length + 1
lgr %r5,%r4 # source length
lgr %r4,%r2 # source address
lgr %r2,%r3 # set destination
lgr %r3,%r5 # destination length = source length
.L6: mvcle %r2,%r4,0 # thats it, MVCLE is your friend
jo .L6
br %r14
.L7: # destructive overlay, can not use mvcle
lgr %r1,%r2 # bcopy is called with source,dest
lgr %r2,%r3 # memmove with dest,source! Oh, well...
lgr %r3,%r1
jg HIDDEN_BUILTIN_JUMPTARGET(memmove)
END(__bcopy)
#ifndef NO_WEAK_ALIAS
weak_alias (__bcopy, bcopy)
#endif
