1/* Vector optimized 32/64 bit S/390 version of memchr.
2 Copyright (C) 2015-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <ifunc-memchr.h>
20#if HAVE_MEMCHR_Z13
21
22# include "sysdep.h"
23# include "asm-syntax.h"
24
25 .text
26
27/* void *memchr (const void *s, int c, size_t n)
28 Scans memory for character c
29 and returns pointer to first c.
30
31 Register usage:
32 -r0=tmp
33 -r1=tmp
34 -r2=s
35 -r3=c
36 -r4=n
37 -r5=current_len
38 -v16=part of s
39 -v17=index of found c
40 -v18=c replicated
41*/
42ENTRY(MEMCHR_Z13)
43
44 .machine "z13"
45 .machinemode "zarch_nohighgprs"
46
47# if !defined __s390x__
48 llgfr %r4,%r4
49# endif /* !defined __s390x__ */
50
51 clgije %r4,0,.Lnf_end /* If len == 0 then exit. */
52
53 vlbb %v16,0(%r2),6 /* Load s until next 4k-byte boundary. */
54 lcbb %r0,0(%r2),6 /* Get bytes to 4k-byte boundary or 16. */
55 llgfr %r0,%r0 /* Convert 32bit to 64bit. */
56
57 vlvgb %v18,%r3,0 /* Generate vector which elements are all c.
58 if c > 255, c will be truncated. */
59 vrepb %v18,%v18,0
60 lghi %r5,16 /* current_len = 16. */
61
62 clgrjhe %r0,%r4,.Llastcmp /* If (bytes to boundary) >= n,
63 jump to lastcmp. */
64
65 vfeebs %v17,%v16,%v18 /* Find c. */
66 vlgvb %r1,%v17,7 /* Load byte index of c. */
67 clgrjl %r1,%r0,.Lfound2 /* Found c is within loaded bytes. */
68
69 /* Align s to 16 byte. */
70 risbgn %r1,%r2,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
71 slr %r5,%r1 /* Compute bytes to 16bytes boundary. */
72
73 lgr %r0,%r5 /* If %r5 + 64 < n? -> loop64. */
74 aghi %r0,64
75 clgrjl %r0,%r4,.Lloop64
76.Llt64:
77 vl %v16,0(%r5,%r2)
78 aghi %r5,16
79 clgrjhe %r5,%r4,.Llastcmp /* Do last compare if curr-len >= n. */
80 vfeebs %v17,%v16,%v18 /* Find c. */
81 jl .Lfound /* Jump away if c was found. */
82
83 vl %v16,0(%r5,%r2)
84 aghi %r5,16
85 clgrjhe %r5,%r4,.Llastcmp
86 vfeebs %v17,%v16,%v18
87 jl .Lfound
88
89 vl %v16,0(%r5,%r2)
90 aghi %r5,16
91 clgrjhe %r5,%r4,.Llastcmp
92 vfeebs %v17,%v16,%v18
93 jl .Lfound
94
95 vl %v16,0(%r5,%r2)
96 aghi %r5,16
97
98.Llastcmp:
99 /* Use comparision result only if located within first n characters.
100 %r5: current_len;
101 %r4: n;
102 (current_len - n): [0...16[
103 first ignored match index: vr-width - (current_len - n) ]0...16]
104 */
105 vfeebs %v17,%v16,%v18 /* Find c. */
106 slgrk %r4,%r5,%r4 /* %r5 = current_len - n. */
107 lghi %r0,16 /* Register width = 16. */
108 vlgvb %r1,%v17,7 /* Extract found index or 16 if all equal. */
109 slr %r0,%r4 /* %r0 = first ignored match index. */
110 clrjl %r1,%r0,.Lfound2 /* Go away if miscompare is below n bytes. */
111 /* c not found within n-bytes. */
112.Lnf_end:
113 lghi %r2,0 /* Return null. */
114 br %r14
115
116.Lfound48:
117 aghi %r5,16
118.Lfound32:
119 aghi %r5,16
120.Lfound16:
121 aghi %r5,16
122.Lfound0:
123 aghi %r5,16
124.Lfound:
125 vlgvb %r1,%v17,7 /* Load byte index of c. */
126.Lfound2:
127 slgfi %r5,16 /* current_len -=16 */
128 algr %r5,%r1 /* Zero byte index is added to current len. */
129 la %r2,0(%r5,%r2) /* Return pointer to c. */
130 br %r14
131
132
133.Lloop64:
134 vl %v16,0(%r5,%r2)
135 vfeebs %v17,%v16,%v18 /* Find c. */
136 jl .Lfound0 /* Jump away if c was found. */
137 vl %v16,16(%r5,%r2)
138 vfeebs %v17,%v16,%v18
139 jl .Lfound16
140 vl %v16,32(%r5,%r2)
141 vfeebs %v17,%v16,%v18
142 jl .Lfound32
143 vl %v16,48(%r5,%r2)
144 vfeebs %v17,%v16,%v18
145 jl .Lfound48
146
147 aghi %r5,64
148 lgr %r0,%r5 /* If %r5 + 64 < n? -> loop64. */
149 aghi %r0,64
150 clgrjl %r0,%r4,.Lloop64
151
152 j .Llt64
153END(MEMCHR_Z13)
154
155# if ! HAVE_MEMCHR_IFUNC
156strong_alias (MEMCHR_Z13, __memchr)
157weak_alias (__memchr, memchr)
158# endif
159
160# if ! HAVE_MEMCHR_Z900_G5 && defined SHARED && IS_IN (libc)
161strong_alias (MEMCHR_Z13, __GI_memchr)
162# endif
163#endif
164

source code of glibc/sysdeps/s390/memchr-vx.S