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/* Vector optimized 32/64 bit S/390 version of strncmp.
Copyright (C) 2015-2024 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
<https://www.gnu.org/licenses/>. */
#include <ifunc-strncmp.h>
#if HAVE_STRNCMP_Z13
# include "sysdep.h"
# include "asm-syntax.h"
.text
/* int strncmp (const char *s1, const char *s2, size_t n)
Compare at most n characters of two strings.
Register usage:
-r0=tmp
-r1=tmp
-r2=s1
-r3=s2
-r4=n
-r5=current_len
-v16=part of s1
-v17=part of s2
-v18=index of unequal
*/
ENTRY(STRNCMP_Z13)
.machine "z13"
.machinemode "zarch_nohighgprs"
# if !defined __s390x__
llgfr %r4,%r4
# endif /* !defined __s390x__ */
clgije %r4,0,.Lend_equal /* Nothing to do if n == 0, */
lghi %r5,0 /* current_len = 0. */
.Lloop:
vlbb %v16,0(%r5,%r2),6 /* Load s1 to block boundary. */
vlbb %v17,0(%r5,%r3),6 /* Load s2 to block boundary. */
lcbb %r0,0(%r5,%r2),6 /* Get loaded byte count of s1. */
jo .Llt16_1 /* Jump away if vr is not fully loaded. */
lcbb %r1,0(%r5,%r3),6 /* Get loaded byte count of s2. */
jo .Llt16_2 /* Jump away if vr is not fully loaded. */
aghi %r5,16 /* Both vrs are fully loaded. */
clgrjhe %r5,%r4,.Llastcmp /* If current_len >= n ->last compare. */
vfenezbs %v18,%v16,%v17 /* Compare not equal with zero search. */
jno .Lfound
vlbb %v16,0(%r5,%r2),6
vlbb %v17,0(%r5,%r3),6
lcbb %r0,0(%r5,%r2),6
jo .Llt16_1
lcbb %r1,0(%r5,%r3),6
jo .Llt16_2
aghi %r5,16
clgrjhe %r5,%r4,.Llastcmp
vfenezbs %v18,%v16,%v17
jno .Lfound
vlbb %v16,0(%r5,%r2),6
vlbb %v17,0(%r5,%r3),6
lcbb %r0,0(%r5,%r2),6
jo .Llt16_1
lcbb %r1,0(%r5,%r3),6
jo .Llt16_2
aghi %r5,16
clgrjhe %r5,%r4,.Llastcmp
vfenezbs %v18,%v16,%v17
jno .Lfound
vlbb %v16,0(%r5,%r2),6
vlbb %v17,0(%r5,%r3),6
lcbb %r0,0(%r5,%r2),6
jo .Llt16_1
lcbb %r1,0(%r5,%r3),6
jo .Llt16_2
aghi %r5,16
clgrjhe %r5,%r4,.Llastcmp
vfenezbs %v18,%v16,%v17
jno .Lfound
j .Lloop
.Llt16_1:
lcbb %r1,0(%r5,%r3),6 /* Get loaded byte count ofs2. */
.Llt16_2:
clr %r0,%r1 /* Compare logical. */
locrh %r0,%r1 /* Compute minimum of bytes loaded. */
algfr %r5,%r0 /* Add smallest loaded bytes to current_len. */
clgrj %r5,%r4,10,.Llastcmp /* If current_len >= n ->last compare. */
vfenezbs %v18,%v16,%v17 /* Compare not equal with zero search. */
vlgvb %r1,%v18,7 /* Get not equal index or 16 if all equal. */
clrjl %r1,%r0,.Lfound /* Jump away if miscompare is within
loaded bytes (index < loaded-bytes) */
j .Lloop
.Llastcmp:
/* Use comparison result only if located within first n characters.
%r0: loaded byte count in vreg;
%r5: current_len;
%r4: n;
(current_len - n): [0...16[
First ignored match index: loaded bytes - (current_len-n): ]0...16]
*/
slgr %r5,%r4 /* %r5 = current_len - n. */
slr %r0,%r5 /* %r0 = first ignored match index. */
vfenezbs %v18,%v16,%v17 /* Compare not equal with zero search. */
vlgvb %r1,%v18,7 /* Get not equal index or 16 if all equal. */
clrjl %r1,%r0,.Lfound /* Jump away if miscompare is within
loaded bytes and below n bytes. */
j .Lend_equal /* Miscompare after n-bytes -> end equal. */
.Lfound:
/* Difference or end of string. */
je .Lend_equal
lghi %r2,1
lghi %r1,-1
locgrl %r2,%r1
br %r14
.Lend_equal:
lghi %r2,0
br %r14
END(STRNCMP_Z13)
# if ! HAVE_STRNCMP_IFUNC
strong_alias (STRNCMP_Z13, strncmp)
# endif
# if ! HAVE_STRNCMP_C && defined SHARED && IS_IN (libc)
strong_alias (STRNCMP_Z13, __GI_strncmp)
# endif
#endif /* HAVE_STRNCMP_Z13 */
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