about summary refs log tree commit diff
path: root/sysdeps/s390/multiarch/wcsncmp-vx.S
blob: e13727b21dee5814fe161bcc827723d29c23cce4 (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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/* Vector optimized 32/64 bit S/390 version of wcsncmp.
   Copyright (C) 2015 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

/* int wcsncmp (const wchar_t *s1, const wchar_t *s2, size_t n)
   Compare at most n characters of two strings.

   Register usage:
   -r0=tmp
   -r1=tmp
   -r2=s1
   -r3=s2
   -r4=n
   -r5=current_len
   -v16=part of s1
   -v17=part of s2
   -v18=index of unequal
*/
ENTRY(__wcsncmp_vx)
	.machine "z13"
	.machinemode "zarch_nohighgprs"

# if !defined __s390x__
	llgfr	%r4,%r4
# endif /* !defined __s390x__ */

	clgije	%r4,0,.Lend_equal /* Nothing to do if n == 0.  */

	/* Check range of n and convert to byte-count.  */
# ifdef __s390x__
	tmhh	%r4,49152	/* Test bit 0 or 1 of maxlen.  */
	lghi	%r1,-4		/* Max byte-count is 18446744073709551612.  */
# else
	tmlh	%r4,49152	/* Test bit 0 or 1 of maxlen.  */
	llilf	%r1,4294967292	/* Max byte-count is 4294967292.  */
# endif /* !__s390x__ */
	sllg	%r4,%r4,2	/* Convert character-count to byte-count.  */
	locgrne	%r4,%r1		/* Use max byte-count, if bit 0/1 was one.  */

	/* Check first character without vector load.  */
	lghi	%r5,4		/* current_len = 4 bytes.  */
	/* Check s1/2[0].  */
	lt	%r0,0(%r2)
	l	%r1,0(%r3)
	je	.Lend_cmp_one_char
	crjne	%r0,%r1,.Lend_cmp_one_char

.Lloop:
	vlbb	%v17,0(%r5,%r3),6 /* Load s2 to block boundary.  */
	vlbb	%v16,0(%r5,%r2),6 /* Load s1 to block boundary.  */
	lcbb	%r0,0(%r5,%r2),6 /* Get loaded byte count of s1.  */
	jo	.Llt16_1	/* Jump away if vector not fully loaded.  */
	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */
	jo	.Llt16_2	/* Jump away if vector not fully loaded.  */
	aghi	%r5,16		/* Both vectors are fully loaded.  */
	vfenezfs %v18,%v16,%v17	/* Compare not equal with zero search.  */
	clgrjhe	%r5,%r4,.Llastcmp /* If current_len >= n ->last compare.  */
	jno	.Lfound

	vlbb	%v17,0(%r5,%r3),6
	vlbb	%v16,0(%r5,%r2),6
	lcbb	%r0,0(%r5,%r2),6
	jo	.Llt16_1
	lcbb	%r1,0(%r5,%r3),6
	jo	.Llt16_2
	aghi	%r5,16
	vfenezfs %v18,%v16,%v17
	clgrjhe	%r5,%r4,.Llastcmp
	jno	.Lfound

	vlbb	%v17,0(%r5,%r3),6
	vlbb	%v16,0(%r5,%r2),6
	lcbb	%r0,0(%r5,%r2),6
	jo	.Llt16_1
	lcbb	%r1,0(%r5,%r3),6
	jo	.Llt16_2
	aghi	%r5,16
	vfenezfs %v18,%v16,%v17
	clgrjhe	%r5,%r4,.Llastcmp
	jno	.Lfound

	vlbb	%v17,0(%r5,%r3),6
	vlbb	%v16,0(%r5,%r2),6
	lcbb	%r0,0(%r5,%r2),6
	jo	.Llt16_1
	lcbb	%r1,0(%r5,%r3),6
	jo	.Llt16_2
	aghi	%r5,16
	vfenezfs %v18,%v16,%v17
	clgrjhe	%r5,%r4,.Llastcmp
	jno	.Lfound

	j	.Lloop

.Llt16_1:
	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */
.Llt16_2:
	clr	%r0,%r1		/* Compare logical.  */
	locrh	%r0,%r1		/* Compute minimum of bytes loaded.  */
	nill	%r0,65532	/* Align bytes loaded to full characters.  */
	jz	.Lcmp_one_char	/* Jump away if no full char is available.  */
.Llt_cmp:
	algfr	%r5,%r0		/* Add smallest loaded bytes to current_len.  */
	vfenezfs %v18,%v16,%v17	/* Compare not equal with zero search.  */
	clgrj	%r5,%r4,10,.Llastcmp /* If current_len >= n -> last compare  */
	vlgvb	%r1,%v18,7	/* Get not equal index or 16 if all equal.  */
	clrjl	%r1,%r0,.Lfound /* Jump away if miscompare is within
				   loaded bytes; (index < loaded-bytes) */
	j	.Lloop

.Lcmp_one_char:
	/* At least one of both strings is not 4-byte aligned
	   and there is no full character before next block-boundary.
	   Compare one character to get over the boundary and
	   proceed with normal loop!  */
	vlef	%v16,0(%r5,%r2),0 /* Load one character.  */
	lghi	%r0,4		/* Loaded byte count is 4.  */
	vlef	%v17,0(%r5,%r3),0
	j	.Llt_cmp	/* Proceed with comparision.  */

.Llastcmp:
	/* Use comparision result only if located within first n characters.
	   %r0: loaded byte count in vreg;
	   %r5: current_len;
	   %r4: n;
	   (current_len - n): [0...16[
	   First ignored match index: loaded bytes - (current_len-n): ]0...16]
	*/
	slgr	%r5,%r4		/* %r5 = current_len - n.  */
	slr	%r0,%r5		/* %r0 = first ignored match index.  */
	vlgvb	%r4,%v18,7	/* Get not equal index or 16 if all equal.  */
	clrjl	%r4,%r0,.Lfound2 /* Jump away if miscompare is within
				     loaded bytes and below n bytes.  */
.Lend_equal:
	lghi	%r2,0
	br	%r14

.Lfound:
	/* Difference or end of string.  */
	/* vfenezf found an unequal element or zero.
	   This instruction compares unsigned words, but wchar_t is signed.
	   Thus we have to compare the found element again.  */
	vlgvb	%r4,%v18,7	/* Extract not equal byte-index.  */
.Lfound2:
	srl	%r4,2		/* And convert it to character-index.  */
	vlgvf	%r0,%v16,0(%r4)	/* Load character-values.  */
	vlgvf	%r1,%v17,0(%r4)
.Lend_cmp_one_char:
	cr	%r0,%r1
	je	.Lend_equal
	lghi	%r2,1
	lghi	%r1,-1
	locgrl	%r2,%r1
	br	%r14
END(__wcsncmp_vx)
#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */