1 /* Vector optimized 32/64 bit S/390 version of strrchr.
2 Copyright (C) 2015-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
19 #include <ifunc-strrchr.h>
24 # include "asm-syntax.h"
28 /* char *strrchr (const char *s, int c)
29 Locate the last character c in string.
32 -r0=loaded bytes in first part of s.
33 -r1=pointer to last occurence of c or NULL if not found.
39 -v17=index of found element
41 -v19=part of s with last occurence of c.
46 .machinemode "zarch_nohighgprs"
48 vlbb %v16,0(%r2),6 /* Load s until next 4k-byte boundary. */
49 lcbb %r0,0(%r2),6 /* Get bytes to 4k-byte boundary or 16. */
51 vlvgb %v18,%r3,0 /* Generate vector which elements are all c.
52 if c > 255, c will be truncated. */
55 lghi %r1,-1 /* Currently no c found. */
56 lghi %r5,0 /* current_len = 0. */
58 vfeezbs %v17,%v16,%v18 /* Find element equal or zero. */
59 vlgvb %r4,%v17,7 /* Load byte index of c/zero or 16. */
60 clrjl %r4,%r0,.Lfound_first_part /* Found c/zero in loaded bytes. */
62 /* Align s to 16 byte. */
63 risbgn %r4,%r2,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
64 lghi %r5,16 /* current_len = 16. */
65 slr %r5,%r4 /* Compute bytes to 16bytes boundary. */
68 vl %v16,0(%r5,%r2) /* Load s. */
69 vfeezbs %v17,%v16,%v18 /* Find element equal with zero search. */
70 jno .Lfound /* Found c/zero (cc=0|1|2). */
72 vfeezbs %v17,%v16,%v18
75 vfeezbs %v17,%v16,%v18
78 vfeezbs %v17,%v16,%v18
82 j .Lloop /* No character and no zero -> loop. */
85 la %r5,16(%r5) /* Use la since aghi would clobber cc. */
91 je .Lzero /* Found zero, but no c before that zero. */
92 /* Save this part of s to check for further matches after reaching
93 the end of the complete string. */
97 jh .Lzero /* Found a zero after the found c. */
98 aghi %r5,16 /* Start search of next part of s. */
102 /* This code is only executed if the found c/zero is whithin loaded
103 bytes. If no c/zero was found (cc==3) the found index = 16, thus
104 this code is not called.
105 Resulting condition code of vector find element equal:
106 cc==0: no c, found zero
107 cc==1: c found, no zero
108 cc==2: c found, found zero after c
109 cc==3: no c, no zero (this case can be ignored). */
110 je .Lzero /* Found zero, but no c before that zero. */
112 locgrne %r1,%r5 /* Mark c as found in first part of s. */
115 jl .Lalign /* No zero (e.g. if vr was fully loaded)
116 -> Align and loop afterwards. */
118 /* Found a zero in vr. If vr was not fully loaded due to block
119 boundary, the remaining bytes are filled with zero and we can't
120 rely on zero indication of condition code here! */
122 vfenezb %v17,%v16,%v16 /* Find zero. */
123 vlgvb %r4,%v17,7 /* Load byte index of zero or 16. */
124 clrjl %r4,%r0,.Lzero /* Zero within loaded bytes -> end. */
125 j .Lalign /* Align and loop afterwards. */
128 vlgvb %r4,%v17,7 /* Load byte index of zero. */
130 la %r2,0(%r5,%r2) /* Return pointer to zero. */
134 /* Reached end of string. Check if one c was found before. */
135 clije %r3,0,.Lend_searched_zero /* Found zero and c is zero. */
137 cgfi %r1,-1 /* No c found -> return NULL. */
141 larl %r3,.Lpermute_mask /* Load permute mask. */
144 /* c was found and is part of v19. */
145 vfenezb %v17,%v19,%v19 /* Find zero. */
146 vlgvb %r4,%v17,7 /* Load byte index of zero or 16. */
148 clgfi %r5,0 /* Loaded byte count in v19 is 16, ... */
149 lochine %r0,16 /* ... if v19 is not the first part of s. */
150 ahi %r0,-1 /* Convert byte count to highest index. */
153 locrl %r4,%r0 /* r4 = min (zero-index, highest-index). */
155 /* Right-shift of v19 to mask bytes after zero. */
156 clije %r4,15,.Lzero_permute /* No shift is needed if highest index
159 slr %r0,%r4 /* Compute byte count for vector shift right. */
160 sll %r0,3 /* Convert to bit count. */
162 vsrlb %v19,%v19,%v17 /* Vector shift right by byte by number of bytes
163 specified in bits 1-4 of byte 7 in v17. */
165 /* Reverse bytes in v19. */
167 vperm %v19,%v19,%v19,%v20 /* Permute v19 to reversed order. */
169 /* Find c in reversed v19. */
170 vfeeb %v19,%v19,%v18 /* Find c. */
172 vlgvb %r3,%v19,7 /* Load byte index of c. */
174 /* Compute index in real s and return. */
176 la %r2,0(%r4,%r2) /* Return pointer to zero. */
179 .byte 0x0F,0x0E,0x0D,0x0C,0x0B,0x0A,0x09,0x08
180 .byte 0x07,0x06,0x05,0x04,0x03,0x02,0x01,0x00
183 # if ! HAVE_STRRCHR_IFUNC
184 strong_alias (STRRCHR_Z13, strrchr)
185 weak_alias (strrchr, rindex)
188 # if ! HAVE_STRRCHR_C && defined SHARED && IS_IN (libc)
189 strong_alias (STRRCHR_Z13, __GI_strrchr)
192 #endif /* HAVE_STRRCHR_Z13 */