about summary refs log tree commit diff
path: root/sysdeps/s390/multiarch/strnlen-vx.S
blob: fc659a956cfc1fa134a9b76df4f935842dd0d61a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/* Vector optimized 32/64 bit S/390 version of strnlen.
   Copyright (C) 2015-2018 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/>.  */

#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)

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

	.text

/* size_t strnlen (const char *s, size_t maxlen)
   Returns the number of characters in s or at most maxlen.

   Register usage:
   -r1=tmp
   -r2=address of string
   -r3=maxlen (number of characters to be read)
   -r4=tmp
   -r5=current_len and return_value
   -v16=part of s
*/
ENTRY(__strnlen_vx)
	.machine "z13"
	.machinemode "zarch_nohighgprs"

# if !defined __s390x__
	llgfr	%r3,%r3
# endif /* !defined __s390x__ */

	clgfi	%r3,0		/* if maxlen == 0, return 0.  */
	locgre	%r2,%r3
	ber	%r14

	vlbb	%v16,0(%r2),6	/* Load s until next 4k-byte boundary.  */
	lcbb	%r1,0(%r2),6	/* Get bytes to 4k-byte boundary or 16.  */
	llgfr	%r1,%r1		/* Convert 32bit to 64bit.  */

	vfenezb	%v16,%v16,%v16	/* Find element not equal with zero search.  */
	clgr	%r1,%r3
	locgrh	%r1,%r3		/* loaded_byte_count
				   = min (loaded_byte_count, maxlen)  */

	vlgvb	%r5,%v16,7	/* Load zero index or 16 if not found.  */
	clr	%r5,%r1		/* If found zero within loaded bytes?  */
	locgrl	%r2,%r5		/* Then copy return value.  */
	blr	%r14		/* And return.  */

	clgr	%r1,%r3		/* If loaded_byte_count == maxlen?  */
	locgre	%r2,%r3		/* Then copy return value.  */
	ber	%r14		/* And return.  */

	/* Align s to 16 byte.  */
	risbgn	%r4,%r2,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15.  */
	lghi	%r5,16		/* current_len = 16.  */
	slr	%r5,%r4		/* Compute bytes to 16bytes boundary.  */

	lgr	%r1,%r5		/* If %r5 + 64 < maxlen? -> loop64.  */
	aghi	%r1,64
	clgrjl	%r1,%r3,.Lloop64

	/* Find zero in max 64byte with aligned s.  */
.Llt64:
	vl	%v16,0(%r5,%r2) /* Load s.  */
	vfenezbs %v16,%v16,%v16	/* Find element not equal with zero search.  */
	je	.Lfound		/* Jump away if zero was found.  */
	aghi	%r5,16
	clgrjhe	%r5,%r3,.Lfound /* current_len >= maxlen -> end.  */
	vl	%v16,0(%r5,%r2)
	vfenezbs %v16,%v16,%v16
	je	.Lfound
	aghi	%r5,16
	clgrjhe	%r5,%r3,.Lfound
	vl	%v16,0(%r5,%r2)
	vfenezbs %v16,%v16,%v16
	je	.Lfound
	aghi	%r5,16
	clgrjhe	%r5,%r3,.Lfound
	vl	%v16,0(%r5,%r2)
	vfenezbs %v16,%v16,%v16
	j	.Lfound

.Lfound48:
	aghi	%r5,16
.Lfound32:
	aghi	%r5,16
.Lfound16:
	aghi	%r5,16
.Lfound:
	vlgvb	%r4,%v16,7	/* Load byte index of zero or 16 if no zero.  */
	algr	%r5,%r4

	clgr	%r5,%r3
	locgrh	%r5,%r3		/* Return min (current_len, maxlen).  */
	lgr	%r2,%r5
	br	%r14

	/* Find zero in 16 byte aligned loop.  */
.Lloop64:
	vl	%v16,0(%r5,%r2) /* Load s.  */
	vfenezbs %v16,%v16,%v16	/* Find element not equal with zero search.  */
	je	.Lfound		/* Jump away if zero was found.  */
	vl	%v16,16(%r5,%r2)
	vfenezbs %v16,%v16,%v16
	je	.Lfound16
	vl	%v16,32(%r5,%r2)
	vfenezbs %v16,%v16,%v16
	je	.Lfound32
	vl	%v16,48(%r5,%r2)
	vfenezbs %v16,%v16,%v16
	je	.Lfound48

	aghi	%r5,64
	lgr	%r1,%r5		/* If %r5 + 64 < maxlen? -> loop64.  */
	aghi	%r1,64
	clgrjl	%r1,%r3,.Lloop64

	j	.Llt64
END(__strnlen_vx)
#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */