glibc/sysdeps/aarch64/multiarch/strlen_generic.S

/* A Generic Optimized strlen implementation for AARCH64.
   Copyright (C) 2018-2019 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/>.  */

/* The actual strlen code is in ../strlen.S.  If we are building libc this file
   defines __strlen_generic.  Otherwise the include of ../strlen.S will define
   the normal __strlen  entry points.  */

#include <sysdep.h>

#if IS_IN (libc)

# define STRLEN __strlen_generic

/* Do not hide the generic version of strlen, we use it internally.  */
# undef libc_hidden_builtin_def
# define libc_hidden_builtin_def(name)

# ifdef SHARED
/* It doesn't make sense to send libc-internal strlen calls through a PLT. */
	.globl __GI_strlen; __GI_strlen = __strlen_generic
# endif
#endif

#include "../strlen.S"
[aarch64] Add an ASIMD variant of strlen for falkor This variant of strlen uses vector loads and operations to reduce the size of the code and also eliminate the non-ascii fallback. This works very well for falkor because of its two vector units and efficient vector ops. In the best case it reduces latency of cases in bench-strlen by 48%, with gains throughout the benchmark. strlen-walk also sees uniform gains in the 5%-15% range. Overall the routine appears to work better than the stock one for falkor regardless of the benchmark, length of string or cache state. The same cannot be said of a53 and a72 though. a53 performance was greatly reduced and for a72 it was a bit of a mixed bag, slightly on the negative side but I reckon it might be fast in some situations. * sysdeps/aarch64/strlen.S (__strlen): Rename to STRLEN. [!STRLEN](STRLEN): Set to __strlen. * sysdeps/aarch64/multiarch/strlen.c: New file. * sysdeps/aarch64/multiarch/strlen_generic.S: Likewise. * sysdeps/aarch64/multiarch/strlen_asimd.S: Likewise. * sysdeps/aarch64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add strlen. * sysdeps/aarch64/multiarch/Makefile (sysdep_routines): Add strlen_generic and strlen_asimd. Reviewed-By: szabolcs.nagy@arm.com CC: pinskia@gmail.com 2018-08-15 17:31:33 +00:00			`/* A Generic Optimized strlen implementation for AARCH64.`
Update copyright dates with scripts/update-copyrights. * All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise. 2019-01-01 00:11:28 +00:00			`Copyright (C) 2018-2019 Free Software Foundation, Inc.`
[aarch64] Add an ASIMD variant of strlen for falkor This variant of strlen uses vector loads and operations to reduce the size of the code and also eliminate the non-ascii fallback. This works very well for falkor because of its two vector units and efficient vector ops. In the best case it reduces latency of cases in bench-strlen by 48%, with gains throughout the benchmark. strlen-walk also sees uniform gains in the 5%-15% range. Overall the routine appears to work better than the stock one for falkor regardless of the benchmark, length of string or cache state. The same cannot be said of a53 and a72 though. a53 performance was greatly reduced and for a72 it was a bit of a mixed bag, slightly on the negative side but I reckon it might be fast in some situations. * sysdeps/aarch64/strlen.S (__strlen): Rename to STRLEN. [!STRLEN](STRLEN): Set to __strlen. * sysdeps/aarch64/multiarch/strlen.c: New file. * sysdeps/aarch64/multiarch/strlen_generic.S: Likewise. * sysdeps/aarch64/multiarch/strlen_asimd.S: Likewise. * sysdeps/aarch64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add strlen. * sysdeps/aarch64/multiarch/Makefile (sysdep_routines): Add strlen_generic and strlen_asimd. Reviewed-By: szabolcs.nagy@arm.com CC: pinskia@gmail.com 2018-08-15 17:31:33 +00:00			`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/>. */`

			`/* The actual strlen code is in ../strlen.S. If we are building libc this file`
			`defines __strlen_generic. Otherwise the include of ../strlen.S will define`
			`the normal __strlen entry points. */`

			`#include <sysdep.h>`

			`#if IS_IN (libc)`

			`# define STRLEN __strlen_generic`

			`/* Do not hide the generic version of strlen, we use it internally. */`
			`# undef libc_hidden_builtin_def`
			`# define libc_hidden_builtin_def(name)`

			`# ifdef SHARED`
			`/* It doesn't make sense to send libc-internal strlen calls through a PLT. */`
			`.globl __GI_strlen; __GI_strlen = __strlen_generic`
			`# endif`
			`#endif`

			`#include "../strlen.S"`