1 /* Vector optimized 32/64 bit S/390 version of strnlen.
2 Copyright (C) 2015-2016 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 <http://www.gnu.org/licenses/>. */
19 #if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
22 # include "asm-syntax.h"
26 /* size_t strnlen (const char *s, size_t maxlen)
27 Returns the number of characters in s or at most maxlen.
32 -r3=maxlen (number of characters to be read)
34 -r5=current_len and return_value
39 .machinemode "zarch_nohighgprs"
41 # if !defined __s390x__
43 # endif /* !defined __s390x__ */
45 clgfi %r3,0 /* if maxlen == 0, return 0. */
49 vlbb %v16,0(%r2),6 /* Load s until next 4k-byte boundary. */
50 lcbb %r1,0(%r2),6 /* Get bytes to 4k-byte boundary or 16. */
51 llgfr %r1,%r1 /* Convert 32bit to 64bit. */
53 vfenezb %v16,%v16,%v16 /* Find element not equal with zero search. */
55 locgrh %r1,%r3 /* loaded_byte_count
56 = min (loaded_byte_count, maxlen) */
58 vlgvb %r5,%v16,7 /* Load zero index or 16 if not found. */
59 clr %r5,%r1 /* If found zero within loaded bytes? */
60 locgrl %r2,%r5 /* Then copy return value. */
61 blr %r14 /* And return. */
63 clgr %r1,%r3 /* If loaded_byte_count == maxlen? */
64 locgre %r2,%r3 /* Then copy return value. */
65 ber %r14 /* And return. */
67 /* Align s to 16 byte. */
68 risbgn %r4,%r2,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
69 lghi %r5,16 /* current_len = 16. */
70 slr %r5,%r4 /* Compute bytes to 16bytes boundary. */
72 lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
74 clgrjl %r1,%r3,.Lloop64
76 /* Find zero in max 64byte with aligned s. */
78 vl %v16,0(%r5,%r2) /* Load s. */
79 vfenezbs %v16,%v16,%v16 /* Find element not equal with zero search. */
80 je .Lfound /* Jump away if zero was found. */
82 clgrjhe %r5,%r3,.Lfound /* current_len >= maxlen -> end. */
84 vfenezbs %v16,%v16,%v16
87 clgrjhe %r5,%r3,.Lfound
89 vfenezbs %v16,%v16,%v16
92 clgrjhe %r5,%r3,.Lfound
94 vfenezbs %v16,%v16,%v16
104 vlgvb %r4,%v16,7 /* Load byte index of zero or 16 if no zero. */
108 locgrh %r5,%r3 /* Return min (current_len, maxlen). */
112 /* Find zero in 16 byte aligned loop. */
114 vl %v16,0(%r5,%r2) /* Load s. */
115 vfenezbs %v16,%v16,%v16 /* Find element not equal with zero search. */
116 je .Lfound /* Jump away if zero was found. */
118 vfenezbs %v16,%v16,%v16
121 vfenezbs %v16,%v16,%v16
124 vfenezbs %v16,%v16,%v16
128 lgr %r1,%r5 /* If %r5 + 64 < maxlen? -> loop64. */
130 clgrjl %r1,%r3,.Lloop64
134 #endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */