1 /* bcopy -- copy a block from source to destination. S/390 version.
2 This file is part of the GNU C Library.
3 Copyright (C) 2000, 2001 Free Software Foundation, Inc.
4 Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
21 %r2 = address of source
22 %r3 = address of destination
23 %r4 = number of bytes to copy. */
26 #include "asm-syntax.h"
30 ltr %r1,%r4 # zero bcopy ?
32 clr %r2,%r3 # check against destructive overlap
37 .L0: ahi %r4,-1 # length - 1
40 ltr %r1,%r1 # < 256 bytes to move ?
42 chi %r1,255 # > 1MB to move ?
44 .L1: mvc 0(256,%r3),0(%r2) # move in 256 byte chunks
48 .L2: bras %r1,.L3 # setup base pointer for execute
49 mvc 0(1,%r3),0(%r2) # instruction for execute
50 .L3: ex %r4,0(%r1) # execute mvc with length ((%r4)&255)+1
53 # data copies > 1MB are faster with mvcle.
54 .L5: ahi %r4,1 # length + 1
55 lr %r5,%r4 # source length
56 lr %r4,%r2 # source address
57 lr %r2,%r3 # set destination
58 lr %r3,%r5 # destination length = source length
59 .L6: mvcle %r2,%r4,0 # thats it, MVCLE is your friend
62 .L7: # destructive overlay, can not use mvcle
63 lr %r1,%r2 # bcopy is called with source,dest
64 lr %r2,%r3 # memmove with dest,source! Oh, well...
69 al %r1,.L9-.L8(%r1) # get address of global offset table
70 # load address of memmove
71 l %r1,memmove@GOT12(%r1)
73 .L9: .long _GLOBAL_OFFSET_TABLE_-.L8
75 al %r1,.L9-.L8(%r1) # load address of memmove
76 br %r1 # jump to memmove
77 .L9: .long memmove-.L8
83 weak_alias (__bcopy, bcopy)