/* 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, 2001, 2005 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, write to the Free   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA   02111-1307 USA.  *//* INPUT PARAMETERS     %r2 = address of source     %r3 = address of destination     %r4 = number of bytes to copy.  */#include "sysdep.h"#include "asm-syntax.h"	.textENTRY(__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_ALIASweak_alias (__bcopy, bcopy)#endif