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/* Vector optimized 32/64 bit S/390 version of strnlen.
Copyright (C) 2015-2017 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) */
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