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/* Vector optimized 32/64 bit S/390 version of strstr.
Copyright (C) 2019-2023 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-strstr.h>
#if HAVE_STRSTR_ARCH13
# include "sysdep.h"
# include "asm-syntax.h"
.text
/* char *strstr (const char *haystack=r2, const char *needle=r3)
Locate a substring. */
ENTRY(STRSTR_ARCH13)
.machine "arch13"
.machinemode "zarch_nohighgprs"
lcbb %r1,0(%r3),6
jo .Lneedle_on_bb /* Needle on block-boundary? */
vl %v18,0(%r3),6 /* Load needle. */
vfenezb %v19,%v18,%v18 /* v19[7] contains the length of needle. */
.Lneedle_loaded:
vlgvb %r4,%v19,7 /* Get index of zero or 16 if not found. */
lghi %r5,17 /* See below: min-skip-partial-match-index. */
cgibe %r4,0,0(%r14) /* Test if needle is zero and return. */
/* The vstrs instruction is able to handle needles up to a length of 16,
but then we may have to load the next part of haystack with a
small offset. This will be slow - see examples:
haystack =mmmmmmmmmmmmmmmm mmmmmmmmmmmmmmmmmm...mmmmmmmmmmmmmmmmmmma
needle = mmmmmmmmmmmmmma0
=> needle_len=15; vstrs reports a partial match; haystack+=2
haystack =mmmmmmmmmmmmmmmm mmmmmmmmmmmmmmmmmm...mmmmmmmmmmmmmmmmmmma
needle = mmmmmmmma0000000
=> needle_len=9; vstrs reports a partial match; haystack+=8 */
# if ! HAVE_STRSTR_Z13
# error The arch13 variant of strstr needs the z13 variant of strstr!
# endif
clgfi %r4,9
jgh STRSTR_Z13
/* In case of a partial match, the vstrs instruction returns the index
of the partial match in a vector-register. Then we have to
reload the string at the "current-position plus this index" and run
vstrs again in order to determine if it was a full match or no match.
Transferring this index from vr to gr, compute the haystack-address
and loading with vl is quite slow as all instructions have data
dependencies. Thus we assume, that a partial match is always at the
first possible index and just load the next part of haystack from
there instead of waiting until the correct index is computed:
min-skip-partial-match-index = (16 - n_len) + 1 */
sgr %r5,%r4
.Lloop:
lcbb %r1,0(%r2),6
jo .Lloop_haystack_on_bb /* Haystack on block-boundary? */
vl %v16,0(%r2) /* Load next part of haystack. */
.Lloop_haystack_loaded:
/* Vector string search with zero search (cc=0 => no match). */
vstrs %v20,%v16,%v18,%v19,0,2
jne .Lloop_vstrs_nonzero_cc
lcbb %r1,16(%r2),6 /* Next part of haystack. */
jo .Lloop_haystack_on_bb16
vl %v16,16(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
jne .Lloop_vstrs_nonzero_cc16
lcbb %r1,32(%r2),6 /* Next part of haystack. */
jo .Lloop_haystack_on_bb32
vl %v16,32(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
jne .Lloop_vstrs_nonzero_cc32
lcbb %r1,48(%r2),6 /* Next part of haystack. */
jo .Lloop_haystack_on_bb48
vl %v16,48(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
jne .Lloop_vstrs_nonzero_cc48
la %r2,64(%r2)
j .Lloop
.Lloop_vstrs_nonzero_cc48:
la %r2,16(%r2)
.Lloop_vstrs_nonzero_cc32:
la %r2,16(%r2)
.Lloop_vstrs_nonzero_cc16:
la %r2,16(%r2)
.Lloop_vstrs_nonzero_cc:
jh .Lend_match_found /* cc == 2 (full match) */
jl .Lend_no_match /* cc == 1 (no match, end of string) */
/* cc == 3 (partial match) See above: min-skip-partial-match-index! */
lcbb %r1,0(%r5,%r2),6
la %r2,0(%r5,%r2)
jo .Lloop_haystack_on_bb
vl %v16,0(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
.Lloop_vstrs_nonzero_cc_loop:
jh .Lend_match_found
jl .Lend_no_match
la %r2,0(%r5,%r2)
je .Lloop
lcbb %r1,0(%r2),6 /* Next part of haystack. */
jo .Lloop_haystack_on_bb
vl %v16,0(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
jh .Lend_match_found
jl .Lend_no_match
la %r2,0(%r5,%r2)
je .Lloop
lcbb %r1,0(%r2),6 /* Next part of haystack. */
jo .Lloop_haystack_on_bb
vl %v16,0(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
jh .Lend_match_found
jl .Lend_no_match
la %r2,0(%r5,%r2)
je .Lloop
lcbb %r1,0(%r2),6 /* Next part of haystack. */
jo .Lloop_haystack_on_bb
vl %v16,0(%r2)
vstrs %v20,%v16,%v18,%v19,0,2
j .Lloop_vstrs_nonzero_cc_loop
.Lend_no_match:
lghi %r2,0
br %r14
.Lend_match_found:
vlgvb %r4,%v20,7
la %r2,0(%r4,%r2)
br %r14
.Lloop_haystack_on_bb48:
la %r2,16(%r2)
.Lloop_haystack_on_bb32:
la %r2,16(%r2)
.Lloop_haystack_on_bb16:
la %r2,16(%r2)
.Lloop_haystack_on_bb:
/* Haystack located on page-boundary. */
ahi %r1,-1 /* vll needs highest index instead of count. */
vll %v16,%r1,0(%r2)
vlvgb %v21,%r1,7
vfenezb %v17,%v16,%v16 /* Search zero in loaded haystack bytes. */
veclb %v17,%v21 /* Zero index <= loaded byte index? */
jle .Lloop_haystack_loaded /* -> v16 contains full haystack. */
vl %v16,0(%r2) /* Load haystack beyond page boundary. */
j .Lloop_haystack_loaded
.Lneedle_on_bb:
/* Needle located on page-boundary. */
ahi %r1,-1 /* vll needs highest index instead of count. */
vll %v18,%r1,0(%r3)
vlvgb %v21,%r1,7
vfenezb %v19,%v18,%v18 /* Search zero in loaded needle bytes. */
veclb %v19,%v21 /* Zero index <= max loaded byte index? */
jle .Lneedle_loaded /* -> v18 contains full needle. */
vl %v18,0(%r3) /* Load needle beyond page boundary. */
vfenezb %v19,%v18,%v18
j .Lneedle_loaded
END(STRSTR_ARCH13)
# if ! HAVE_STRSTR_IFUNC
strong_alias (STRSTR_ARCH13, strstr)
# endif
# if STRSTR_Z13_ONLY_USED_AS_FALLBACK && defined SHARED && IS_IN (libc)
strong_alias (STRSTR_ARCH13, __GI_strstr)
# endif
#endif
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