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/* Vector optimized 32/64 bit S/390 version of strlen.
Copyright (C) 2015-2018 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 strlen (const char *s)
Returns length of string s.
Register usage:
-r1=bytes to 4k-byte boundary
-r2=s
-r3=tmp
-r4=tmp
-r5=current_len and return_value
-v16=part of s
*/
ENTRY(__strlen_vx)
.machine "z13"
.machinemode "zarch_nohighgprs"
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. */
vfenezb %v16,%v16,%v16 /* Find element not equal with zero search. */
vlgvb %r4,%v16,7 /* Load zero index or 16 if not found. */
clr %r4,%r1 /* If found zero within loaded bytes? */
locgrl %r2,%r4 /* Then copy return value. */
blr %r14 /* And return. */
/* Align s to 16 byte. */
risbgn %r3,%r2,60,128+63,0 /* %r3 = bits 60-63 of %r2 'and' 15. */
lghi %r5,16 /* current_len = 16. */
slr %r5,%r3 /* Compute bytes to 16bytes boundary. */
/* Find zero in 16 byte aligned loop. */
.Lloop:
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
j .Lloop /* No zero found -> loop. */
.Lfound48:
aghi %r5,16
.Lfound32:
aghi %r5,16
.Lfound16:
aghi %r5,16
.Lfound:
vlgvb %r2,%v16,7 /* Load byte index of zero. */
algr %r2,%r5
br %r14
END(__strlen_vx)
#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
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