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PowerPC: strrchr optimization for POWER7/PPC64
This patch optimizes strrchr() for ppc64. It uses aligned memory access along with cmpb instruction and CPU prefetch to avoid cache misses for speed improvement.
This commit is contained in:
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12
ChangeLog
12
ChangeLog
@ -1,3 +1,15 @@
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2014-03-03 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
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* sysdeps/powerpc/powerpc64/power7/strrchr.S: New file.
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* sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strrchr multiarch
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implementation.
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* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c:
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(__libc_ifunc_impl_list): Likewise.
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* sysdeps/powerpc/powerpc64/multiarch/strrchr.c: New file.
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* sysdeps/powerpc/powerpc64/multiarch/strrchr-ppc64.c: New file.
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* sysdeps/powerpc/powerpc64/multiarch/strrchr-power7.S: New file.
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* string/strrchr.c: Define STRRCHR.
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2014-02-28 Ondřej Bílka <neleai@seznam.cz>
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* benchtest/bench-strtok.c (simple_strtok): Delete.
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@ -19,9 +19,13 @@
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#undef strrchr
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#ifndef STRRCHR
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# define STRRCHR strrchr
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#endif
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/* Find the last occurrence of C in S. */
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char *
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strrchr (const char *s, int c)
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STRRCHR (const char *s, int c)
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{
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const char *found, *p;
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@ -13,7 +13,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
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wcschr-power6 wcschr-ppc64 wcsrchr-power7 wcsrchr-power6 \
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wcsrchr-ppc64 wcscpy-power7 wcscpy-power6 wcscpy-ppc64 \
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wordcopy-power7 wordcopy-power6 wordcopy-ppc64 \
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strcpy-power7 strcpy-ppc64 stpcpy-power7 stpcpy-ppc64
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strcpy-power7 strcpy-ppc64 stpcpy-power7 stpcpy-ppc64 \
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strrchr-power7 strrchr-ppc64
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CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
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CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops
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@ -238,5 +238,13 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
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IFUNC_IMPL_ADD (array, i, wcscpy, 1,
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__wcscpy_ppc))
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/* Support sysdeps/powerpc/powerpc64/multiarch/strrchr.c. */
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IFUNC_IMPL (i, name, strrchr,
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IFUNC_IMPL_ADD (array, i, strrchr,
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hwcap & PPC_FEATURE_HAS_VSX,
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__strrchr_power7)
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IFUNC_IMPL_ADD (array, i, strrchr, 1,
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__strrchr_ppc))
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return i;
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}
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39
sysdeps/powerpc/powerpc64/multiarch/strrchr-power7.S
Normal file
39
sysdeps/powerpc/powerpc64/multiarch/strrchr-power7.S
Normal file
@ -0,0 +1,39 @@
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/* Optimized strrchr implementation for POWER7.
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Copyright (C) 2014 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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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#undef ENTRY
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#define ENTRY(name) \
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.section ".text"; \
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ENTRY_2(__strrchr_power7) \
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.align ALIGNARG(2); \
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BODY_LABEL(__strrchr_power7): \
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cfi_startproc; \
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LOCALENTRY(__strrchr_power7)
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#undef END
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#define END(name) \
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cfi_endproc; \
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TRACEBACK(__strrchr_power7) \
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END_2(__strrchr_power7)
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#undef libc_hidden_builtin_def
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#define libc_hidden_builtin_def(name)
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#include <sysdeps/powerpc/powerpc64/power7/strrchr.S>
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33
sysdeps/powerpc/powerpc64/multiarch/strrchr-ppc64.c
Normal file
33
sysdeps/powerpc/powerpc64/multiarch/strrchr-ppc64.c
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@ -0,0 +1,33 @@
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/* Copyright (C) 2014 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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<http://www.gnu.org/licenses/>. */
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#include <string.h>
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#define STRRCHR __strrchr_ppc
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#undef weak_alias
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#define weak_alias(name, aliasname) \
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extern __typeof (__strrchr_ppc) aliasname \
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__attribute__ ((weak, alias ("__strrchr_ppc")));
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#if !defined(NOT_IN_libc) && defined(SHARED)
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# undef libc_hidden_builtin_def
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# define libc_hidden_builtin_def(name) \
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__hidden_ver1(__strrchr_ppc, __GI_strrchr, __strrchr_ppc);
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#endif
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extern __typeof (strrchr) __strrchr_ppc attribute_hidden;
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#include <string/strrchr.c>
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35
sysdeps/powerpc/powerpc64/multiarch/strrchr.c
Normal file
35
sysdeps/powerpc/powerpc64/multiarch/strrchr.c
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@ -0,0 +1,35 @@
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/* Multiple versions of strrchr. PowerPC64 version.
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Copyright (C) 2014 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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<http://www.gnu.org/licenses/>. */
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/* Define multiple versions only for definition in libc. */
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#ifndef NOT_IN_libc
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# include <string.h>
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# include <shlib-compat.h>
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# include "init-arch.h"
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extern __typeof (strrchr) __strrchr_ppc attribute_hidden;
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extern __typeof (strrchr) __strrchr_power7 attribute_hidden;
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/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
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ifunc symbol properly. */
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libc_ifunc (strrchr,
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(hwcap & PPC_FEATURE_HAS_VSX)
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? __strrchr_power7
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: __strrchr_ppc);
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weak_alias (strrchr, rindex)
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#endif
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255
sysdeps/powerpc/powerpc64/power7/strrchr.S
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255
sysdeps/powerpc/powerpc64/power7/strrchr.S
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@ -0,0 +1,255 @@
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/* Optimized strrchr implementation for PowerPC64/POWER7 using cmpb insn.
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Copyright (C) 2014 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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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* int [r3] strrchr (char *s [r3], int c [r4]) */
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.machine power7
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ENTRY (strrchr)
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CALL_MCOUNT 2
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dcbt 0,r3
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clrrdi r8,r3,3 /* Align the address to doubleword boundary. */
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cmpdi cr7,r4,0
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ld r12,0(r8) /* Load doubleword from memory. */
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li r9,0 /* used to store last occurence */
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li r0,0 /* Doubleword with null chars to use
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with cmpb. */
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rlwinm r6,r3,3,26,28 /* Calculate padding. */
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beq cr7,L(null_match)
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/* Replicate byte to doubleword. */
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insrdi r4,r4,8,48
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insrdi r4,r4,16,32
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insrdi r4,r4,32,0
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/* r4 is changed now ,if its passed as more chars
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check for null again */
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cmpdi cr7,r4,0
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beq cr7,L(null_match)
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/* Now r4 has a doubleword of c bytes and r0 has
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a doubleword of null bytes. */
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cmpb r10,r12,r4 /* Compare each byte against c byte. */
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cmpb r11,r12,r0 /* Compare each byte against null byte. */
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/* Move the doublewords left and right to discard the bits that are
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not part of the string and bring them back as zeros. */
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#ifdef __LITTLE_ENDIAN__
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srd r10,r10,r6
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srd r11,r11,r6
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sld r10,r10,r6
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sld r11,r11,r6
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#else
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sld r10,r10,r6
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sld r11,r11,r6
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srd r10,r10,r6
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srd r11,r11,r6
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#endif
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or r5,r10,r11 /* OR the results to speed things up. */
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cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes
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have been found. */
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bne cr7,L(done)
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L(align):
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mtcrf 0x01,r8
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/* Are we now aligned to a doubleword boundary? If so, skip to
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the main loop. Otherwise, go through the alignment code. */
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bt 28,L(loop)
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/* Handle WORD2 of pair. */
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ldu r12,8(r8)
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cmpb r10,r12,r4
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cmpb r11,r12,r0
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or r5,r10,r11
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cmpdi cr7,r5,0
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bne cr7,L(done)
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b L(loop) /* We branch here (rather than falling through)
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to skip the nops due to heavy alignment
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of the loop below. */
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.p2align 5
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L(loop):
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/* Load two doublewords, compare and merge in a
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single register for speed. This is an attempt
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to speed up the null-checking process for bigger strings. */
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ld r12,8(r8)
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ldu r7,16(r8)
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cmpb r10,r12,r4
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cmpb r11,r12,r0
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cmpb r6,r7,r4
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cmpb r7,r7,r0
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or r12,r10,r11
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or r5,r6,r7
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or r5,r12,r5
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cmpdi cr7,r5,0
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beq cr7,L(loop)
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/* OK, one (or both) of the doublewords contains a c/null byte. Check
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the first doubleword and decrement the address in case the first
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doubleword really contains a c/null byte. */
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cmpdi cr6,r12,0
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addi r8,r8,-8
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bne cr6,L(done)
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/* The c/null byte must be in the second doubleword. Adjust the
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address again and move the result of cmpb to r10 so we can calculate
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the pointer. */
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mr r10,r6
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mr r11,r7
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addi r8,r8,8
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/* r10/r11 have the output of the cmpb instructions, that is,
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0xff in the same position as the c/null byte in the original
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doubleword from the string. Use that to calculate the pointer. */
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L(done):
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/* if there are more than one 0xff in r11, find the first pos of ff
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in r11 and fill r10 with 0 from that position */
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cmpdi cr7,r11,0
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beq cr7,L(no_null)
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#ifdef __LITTLE_ENDIAN__
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addi r3,r11,-1
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andc r3,r3,r11
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popcntd r0,r3
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#else
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cntlzd r0,r11
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#endif
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subfic r0,r0,63
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li r6,-1
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#ifdef __LITTLE_ENDIAN__
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srd r0,r6,r0
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#else
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sld r0,r6,r0
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#endif
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and r10,r0,r10
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L(no_null):
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#ifdef __LITTLE_ENDIAN__
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cntlzd r0,r10 /* Count leading zeros before c matches. */
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addi r3,r10,-1
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andc r3,r3,r10
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addi r10,r11,-1
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andc r10,r10,r11
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cmpld cr7,r3,r10
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bgt cr7,L(no_match)
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#else
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addi r3,r10,-1 /* Count trailing zeros before c matches. */
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andc r3,r3,r10
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popcntd r0,r3
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cmpld cr7,r11,r10
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bgt cr7,L(no_match)
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#endif
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srdi r0,r0,3 /* Convert trailing zeros to bytes. */
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subfic r0,r0,7
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add r9,r8,r0 /* Return address of the matching c byte
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or null in case c was not found. */
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li r0,0
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cmpdi cr7,r11,0 /* If r11 == 0, no null's have been found. */
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beq cr7,L(align)
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.align 4
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L(no_match):
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mr r3,r9
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blr
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/* We are here because strrchr was called with a null byte. */
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.align 4
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L(null_match):
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/* r0 has a doubleword of null bytes. */
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cmpb r5,r12,r0 /* Compare each byte against null bytes. */
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/* Move the doublewords left and right to discard the bits that are
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not part of the string and bring them back as zeros. */
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#ifdef __LITTLE_ENDIAN__
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srd r5,r5,r6
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sld r5,r5,r6
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#else
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sld r5,r5,r6
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srd r5,r5,r6
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#endif
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cmpdi cr7,r5,0 /* If r10 == 0, no c or null bytes
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have been found. */
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bne cr7,L(done_null)
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mtcrf 0x01,r8
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/* Are we now aligned to a quadword boundary? If so, skip to
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the main loop. Otherwise, go through the alignment code. */
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bt 28,L(loop_null)
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/* Handle WORD2 of pair. */
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ldu r12,8(r8)
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cmpb r5,r12,r0
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cmpdi cr7,r5,0
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bne cr7,L(done_null)
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b L(loop_null) /* We branch here (rather than falling through)
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to skip the nops due to heavy alignment
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of the loop below. */
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/* Main loop to look for the end of the string. Since it's a
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small loop (< 8 instructions), align it to 32-bytes. */
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.p2align 5
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L(loop_null):
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/* Load two doublewords, compare and merge in a
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single register for speed. This is an attempt
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to speed up the null-checking process for bigger strings. */
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ld r12,8(r8)
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ldu r11,16(r8)
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cmpb r5,r12,r0
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cmpb r10,r11,r0
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or r6,r5,r10
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cmpdi cr7,r6,0
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beq cr7,L(loop_null)
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/* OK, one (or both) of the doublewords contains a null byte. Check
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the first doubleword and decrement the address in case the first
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doubleword really contains a null byte. */
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cmpdi cr6,r5,0
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addi r8,r8,-8
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bne cr6,L(done_null)
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/* The null byte must be in the second doubleword. Adjust the address
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again and move the result of cmpb to r10 so we can calculate the
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pointer. */
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mr r5,r10
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addi r8,r8,8
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/* r5 has the output of the cmpb instruction, that is, it contains
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0xff in the same position as the null byte in the original
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doubleword from the string. Use that to calculate the pointer. */
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L(done_null):
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#ifdef __LITTLE_ENDIAN__
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addi r0,r5,-1
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andc r0,r0,r5
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popcntd r0,r0
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#else
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cntlzd r0,r5 /* Count leading zeros before the match. */
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#endif
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srdi r0,r0,3 /* Convert trailing zeros to bytes. */
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add r3,r8,r0 /* Return address of the matching null byte. */
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blr
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END (strrchr)
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weak_alias (strrchr, rindex)
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libc_hidden_builtin_def (strrchr)
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