1/* strncpy - copy at most n characters from a string from source to
2   destination.  64 bit S/390 version
3   Copyright (C) 2001-2022 Free Software Foundation, Inc.
4   This file is part of the GNU C Library.
5
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.
10
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.
15
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   <https://www.gnu.org/licenses/>.  */
19
20/* INPUT PARAMETERS
21     %r2 = address of destination (dst)
22     %r3 = address of source (src)
23     %r4 = max of bytes to copy.  */
24
25#include <ifunc-strncpy.h>
26#include "sysdep.h"
27#include "asm-syntax.h"
28
29#if HAVE_STRNCPY_Z900_G5
30ENTRY(STRNCPY_Z900_G5)
31	.text
32	stg   %r2,48(%r15)	    # save dst pointer
33	slgr  %r2,%r3		    # %r3 points to src, %r2+%r3 to dst
34	lghi  %r1,7
35	ngr   %r1,%r4		    # last 3 bits of # bytes
36	srlg  %r4,%r4,3
37	ltgr  %r4,%r4		    # less than 8 bytes to copy ?
38	jz    .L1
39	bras  %r5,.L0		    # enter loop & load address of a 0
40	.long 0
41.L0:	icmh  %r0,8,0(%r3)	    # first byte
42	jz    .L3
43	icmh  %r0,4,1(%r3)	    # second byte
44	jz    .L4
45	icmh  %r0,2,2(%r3)	    # third byte
46	jz    .L5
47	icmh  %r0,1,3(%r3)	    # fourth byte
48	jz    .L6
49	icm   %r0,8,4(%r3)	    # fifth byte
50	jz    .L7
51	icm   %r0,4,5(%r3)	    # sixth byte
52	jz    .L8
53	icm   %r0,2,6(%r3)	    # seventh byte
54	jz    .L9
55	icm   %r0,1,7(%r3)	    # eigth byte
56	jz    .L10
57	stg   %r0,0(%r2,%r3)	    # store all eight to dest.
58	la    %r3,8(%r3)
59	brct  %r4,.L0
60.L1:	ltgr  %r1,%r1
61	jz    .Lexit
62.L2:	icm   %r0,1,0(%r3)
63	stc   %r0,0(%r2,%r3)
64	la    %r3,1(%r3)
65	jz    .L11
66	brct  %r1,.L2
67	j     .Lexit
68.L3:	icmh  %r0,4,0(%r5)
69.L4:	icmh  %r0,2,0(%r5)
70.L5:	icmh  %r0,1,0(%r5)
71.L6:	icm   %r0,8,0(%r5)
72.L7:	icm   %r0,4,0(%r5)
73.L8:	icm   %r0,2,0(%r5)
74.L9:	icm   %r0,1,0(%r5)
75.L10:	stg   %r0,0(%r2,%r3)
76	la    %r3,8(%r3)
77	aghi  %r4,-1
78	j     .L12
79.L11:	aghi  %r1,-1
80.L12:	sllg  %r4,%r4,3
81	algr  %r4,%r1
82	algr  %r2,%r3		    # start of dst area to be zeroed
83	lgr   %r3,%r4
84	slgr  %r4,%r4
85	slgr  %r5,%r5
86.L13:	mvcle %r2,%r4,0		    # pad dst with zeroes
87	jo    .L13
88.Lexit: lg    %r2,48(%r15)	    # return dst pointer
89	br    %r14
90END(STRNCPY_Z900_G5)
91
92# if ! HAVE_STRNCPY_IFUNC
93strong_alias (STRNCPY_Z900_G5, strncpy)
94# endif
95
96# if defined SHARED && IS_IN (libc)
97strong_alias (STRNCPY_Z900_G5, __GI_strncpy)
98# endif
99#endif
100