/* memcpy - copy a block from source to destination.  64 bit 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, write to the Free   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA   02111-1307 USA.  *//* 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"	.textENTRY(memcpy)	ltgr	%r4,%r4	jz	.L3	aghi	%r4,-1		    # length - 1	lgr	%r1,%r2		    # copy destination address	srlg	%r5,%r4,8	ltgr    %r5,%r5             # < 256 bytes to mvoe ?	jz	.L1	chi     %r5,255             # > 1 MB to move ?	jh	.L4.L0:	mvc	0(256,%r1),0(%r3)   # move in 256 byte chunks	la	%r1,256(%r1)	la	%r3,256(%r3)	brctg	%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:	aghi    %r4,1               # length + 1	lgr	%r5,%r4	            # source length	lgr	%r4,%r3             # source address	lgr	%r3,%r5             # destination length = source length.L5:	mvcle	%r2,%r4,0           # thats it, MVCLE is your friend	jo	.L5	lgr     %r2,%r1             # return destination address	br	%r14END(memcpy)libc_hidden_builtin_def (memcpy)