glibc/sysdeps/s390/s390-64/memcpy.S

/* memcpy - copy a block from source to destination.  64 bit S/390 version.
   Copyright (C) 2012-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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/>.  */


#include <sysdep.h>
#include "asm-syntax.h"

/* INPUT PARAMETERS
     %r2 = address of destination memory area
     %r3 = address of source memory area
     %r4 = number of bytes to copy.  */


       .text
ENTRY(__mempcpy)
	.machine "z900"
	lgr     %r1,%r2             # Use as dest
	la      %r2,0(%r4,%r2)      # Return dest + n
	j	.L_Z900_start
END(__mempcpy)
#ifndef USE_MULTIARCH
libc_hidden_def (__mempcpy)
weak_alias (__mempcpy, mempcpy)
libc_hidden_builtin_def (mempcpy)
#endif

ENTRY(memcpy)
	.machine "z900"
	lgr     %r1,%r2             # r1: Use as dest ; r2: Return dest
.L_Z900_start:
	ltgr    %r4,%r4
	je      .L_Z900_4
	aghi    %r4,-1
	srlg    %r5,%r4,8
	ltgr    %r5,%r5
	jne     .L_Z900_13
.L_Z900_3:
	larl    %r5,.L_Z900_15
	ex      %r4,0(%r5)
.L_Z900_4:
	br      %r14
.L_Z900_13:
	cghi	%r5,4096            # Switch to mvcle for copies >1MB
	jh      __memcpy_mvcle
.L_Z900_12:
	mvc     0(256,%r1),0(%r3)
	la      %r1,256(%r1)
	la      %r3,256(%r3)
	brctg   %r5,.L_Z900_12
	j       .L_Z900_3
.L_Z900_15:
	mvc     0(1,%r1),0(%r3)
END(memcpy)
#ifndef USE_MULTIARCH
libc_hidden_builtin_def (memcpy)
#endif

ENTRY(__memcpy_mvcle)
	# Using as standalone function will result in unexpected
	# results since the length field is incremented by 1 in order to
	# compensate the changes already done in the functions above.
	lgr     %r0,%r2             # backup return dest [ + n ]
	aghi    %r4,1               # length + 1
	lgr     %r5,%r4             # source length
	lgr     %r4,%r3             # source address
	lgr     %r2,%r1             # destination address
	lgr     %r3,%r5             # destination length = source length
.L_MVCLE_1:
	mvcle   %r2,%r4,0           # thats it, MVCLE is your friend
	jo      .L_MVCLE_1
	lgr     %r2,%r0             # return destination address
	br      %r14
END(__memcpy_mvcle)