1 /* strncpy - copy at most n characters from a string from source to
2 destination. For IBM S390
3 This file is part of the GNU C Library.
4 Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc.
5 Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <http://www.gnu.org/licenses/>. */
22 * R2 = address of destination (dst)
23 * R3 = address of source (src)
24 * R4 = max of bytes to copy
28 #include "asm-syntax.h"
32 st %r2,24(%r15) # save dst pointer
33 slr %r2,%r3 # %r3 points to src, %r2+%r3 to dst
35 nr %r1,%r4 # last 2 bits of # bytes
37 ltr %r4,%r4 # less than 4 bytes to copy ?
39 bras %r5,.L0 # enter loop & load address of a 0
41 .L0: icm %r0,8,0(%r3) # first byte
43 icm %r0,4,1(%r3) # second byte
45 icm %r0,2,2(%r3) # third byte
47 icm %r0,1,3(%r3) # fourth byte
49 st %r0,0(%r2,%r3) # store all four to dest.
63 .L6: st %r0,0(%r2,%r3)
70 alr %r2,%r3 # start of dst area to be zeroed
74 .L9: mvcle %r2,%r4,0 # pad dst with zeroes
76 .Lexit: l %r2,24(%r15) # return dst pointer
79 libc_hidden_builtin_def (strncpy)