180 lines
6.0 KiB
ArmAsm
180 lines
6.0 KiB
ArmAsm
/* Vector optimized 32/64 bit S/390 version of strstr.
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Copyright (C) 2019-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <ifunc-strstr.h>
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#if HAVE_STRSTR_ARCH13
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# include "sysdep.h"
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# include "asm-syntax.h"
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.text
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/* char *strstr (const char *haystack=r2, const char *needle=r3)
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Locate a substring. */
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ENTRY(STRSTR_ARCH13)
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.machine "arch13"
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.machinemode "zarch_nohighgprs"
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lcbb %r1,0(%r3),6
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jo .Lneedle_on_bb /* Needle on block-boundary? */
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vl %v18,0(%r3),6 /* Load needle. */
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vfenezb %v19,%v18,%v18 /* v19[7] contains the length of needle. */
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.Lneedle_loaded:
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vlgvb %r4,%v19,7 /* Get index of zero or 16 if not found. */
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lghi %r5,17 /* See below: min-skip-partial-match-index. */
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cgibe %r4,0,0(%r14) /* Test if needle is zero and return. */
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/* The vstrs instruction is able to handle needles up to a length of 16,
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but then we may have to load the next part of haystack with a
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small offset. This will be slow - see examples:
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haystack =mmmmmmmmmmmmmmmm mmmmmmmmmmmmmmmmmm...mmmmmmmmmmmmmmmmmmma
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needle = mmmmmmmmmmmmmma0
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=> needle_len=15; vstrs reports a partial match; haystack+=2
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haystack =mmmmmmmmmmmmmmmm mmmmmmmmmmmmmmmmmm...mmmmmmmmmmmmmmmmmmma
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needle = mmmmmmmma0000000
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=> needle_len=9; vstrs reports a partial match; haystack+=8 */
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# if ! HAVE_STRSTR_Z13
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# error The arch13 variant of strstr needs the z13 variant of strstr!
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# endif
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clgfi %r4,9
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jgh STRSTR_Z13
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/* In case of a partial match, the vstrs instruction returns the index
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of the partial match in a vector-register. Then we have to
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reload the string at the "current-position plus this index" and run
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vstrs again in order to determine if it was a full match or no match.
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Transferring this index from vr to gr, compute the haystack-address
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and loading with vl is quite slow as all instructions have data
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dependencies. Thus we assume, that a partial match is always at the
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first possible index and just load the next part of haystack from
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there instead of waiting until the correct index is computed:
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min-skip-partial-match-index = (16 - n_len) + 1 */
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sgr %r5,%r4
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.Lloop:
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lcbb %r1,0(%r2),6
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jo .Lloop_haystack_on_bb /* Haystack on block-boundary? */
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vl %v16,0(%r2) /* Load next part of haystack. */
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.Lloop_haystack_loaded:
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/* Vector string search with zero search (cc=0 => no match). */
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vstrs %v20,%v16,%v18,%v19,0,2
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jne .Lloop_vstrs_nonzero_cc
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lcbb %r1,16(%r2),6 /* Next part of haystack. */
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jo .Lloop_haystack_on_bb16
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vl %v16,16(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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jne .Lloop_vstrs_nonzero_cc16
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lcbb %r1,32(%r2),6 /* Next part of haystack. */
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jo .Lloop_haystack_on_bb32
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vl %v16,32(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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jne .Lloop_vstrs_nonzero_cc32
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lcbb %r1,48(%r2),6 /* Next part of haystack. */
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jo .Lloop_haystack_on_bb48
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vl %v16,48(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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jne .Lloop_vstrs_nonzero_cc48
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la %r2,64(%r2)
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j .Lloop
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.Lloop_vstrs_nonzero_cc48:
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la %r2,16(%r2)
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.Lloop_vstrs_nonzero_cc32:
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la %r2,16(%r2)
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.Lloop_vstrs_nonzero_cc16:
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la %r2,16(%r2)
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.Lloop_vstrs_nonzero_cc:
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jh .Lend_match_found /* cc == 2 (full match) */
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jl .Lend_no_match /* cc == 1 (no match, end of string) */
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/* cc == 3 (partial match) See above: min-skip-partial-match-index! */
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lcbb %r1,0(%r5,%r2),6
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la %r2,0(%r5,%r2)
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jo .Lloop_haystack_on_bb
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vl %v16,0(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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.Lloop_vstrs_nonzero_cc_loop:
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jh .Lend_match_found
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jl .Lend_no_match
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la %r2,0(%r5,%r2)
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je .Lloop
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lcbb %r1,0(%r2),6 /* Next part of haystack. */
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jo .Lloop_haystack_on_bb
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vl %v16,0(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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jh .Lend_match_found
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jl .Lend_no_match
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la %r2,0(%r5,%r2)
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je .Lloop
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lcbb %r1,0(%r2),6 /* Next part of haystack. */
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jo .Lloop_haystack_on_bb
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vl %v16,0(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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jh .Lend_match_found
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jl .Lend_no_match
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la %r2,0(%r5,%r2)
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je .Lloop
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lcbb %r1,0(%r2),6 /* Next part of haystack. */
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jo .Lloop_haystack_on_bb
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vl %v16,0(%r2)
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vstrs %v20,%v16,%v18,%v19,0,2
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j .Lloop_vstrs_nonzero_cc_loop
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.Lend_no_match:
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lghi %r2,0
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br %r14
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.Lend_match_found:
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vlgvb %r4,%v20,7
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la %r2,0(%r4,%r2)
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br %r14
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.Lloop_haystack_on_bb48:
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la %r2,16(%r2)
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.Lloop_haystack_on_bb32:
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la %r2,16(%r2)
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.Lloop_haystack_on_bb16:
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la %r2,16(%r2)
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.Lloop_haystack_on_bb:
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/* Haystack located on page-boundary. */
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ahi %r1,-1 /* vll needs highest index instead of count. */
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vll %v16,%r1,0(%r2)
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vlvgb %v21,%r1,7
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vfenezb %v17,%v16,%v16 /* Search zero in loaded haystack bytes. */
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veclb %v17,%v21 /* Zero index <= loaded byte index? */
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jle .Lloop_haystack_loaded /* -> v16 contains full haystack. */
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vl %v16,0(%r2) /* Load haystack beyond page boundary. */
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j .Lloop_haystack_loaded
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.Lneedle_on_bb:
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/* Needle located on page-boundary. */
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ahi %r1,-1 /* vll needs highest index instead of count. */
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vll %v18,%r1,0(%r3)
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vlvgb %v21,%r1,7
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vfenezb %v19,%v18,%v18 /* Search zero in loaded needle bytes. */
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veclb %v19,%v21 /* Zero index <= max loaded byte index? */
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jle .Lneedle_loaded /* -> v18 contains full needle. */
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vl %v18,0(%r3) /* Load needle beyond page boundary. */
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vfenezb %v19,%v18,%v18
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j .Lneedle_loaded
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END(STRSTR_ARCH13)
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# if ! HAVE_STRSTR_IFUNC
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strong_alias (STRSTR_ARCH13, strstr)
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# endif
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# if STRSTR_Z13_ONLY_USED_AS_FALLBACK && defined SHARED && IS_IN (libc)
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strong_alias (STRSTR_ARCH13, __GI_strstr)
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# endif
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#endif
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