From: "Richard Earnshaw (lists)" <Richard.Earnshaw@arm.com>
To: Sebastian Huber <sebastian.huber@embedded-brains.de>,
newlib@sourceware.org
Subject: Re: [PATCH] ARM: Optimize IEEE-754 sqrt implementation
Date: Tue, 21 Mar 2017 10:08:00 -0000 [thread overview]
Message-ID: <e1321678-7abe-c427-06dc-345bebe0d925@arm.com> (raw)
In-Reply-To: <1490082540-22841-1-git-send-email-sebastian.huber@embedded-brains.de>
On 21/03/17 07:49, Sebastian Huber wrote:
> Use the vsqrt.f64 and vsqrt.f32 instructions if available.
This is OK (and good catch on the VFP9 erratum).
Thanks.
R.
> ---
> newlib/libm/machine/arm/Makefile.am | 2 ++
> newlib/libm/machine/arm/Makefile.in | 17 +++++++++++++-
> newlib/libm/machine/arm/e_sqrt.c | 45 +++++++++++++++++++++++++++++++++++++
> newlib/libm/machine/arm/ef_sqrt.c | 45 +++++++++++++++++++++++++++++++++++++
> 4 files changed, 108 insertions(+), 1 deletion(-)
> create mode 100644 newlib/libm/machine/arm/e_sqrt.c
> create mode 100644 newlib/libm/machine/arm/ef_sqrt.c
>
> diff --git a/newlib/libm/machine/arm/Makefile.am b/newlib/libm/machine/arm/Makefile.am
> index f0ab84f..1f10a7a 100644
> --- a/newlib/libm/machine/arm/Makefile.am
> +++ b/newlib/libm/machine/arm/Makefile.am
> @@ -6,6 +6,8 @@ INCLUDES = -I $(newlib_basedir)/../newlib/libm/common $(NEWLIB_CFLAGS) \
> $(CROSS_CFLAGS) $(TARGET_CFLAGS)
>
> LIB_SOURCES = \
> + e_sqrt.c \
> + ef_sqrt.c \
> s_ceil.c \
> s_floor.c \
> s_nearbyint.c \
> diff --git a/newlib/libm/machine/arm/Makefile.in b/newlib/libm/machine/arm/Makefile.in
> index 9b27356..5088db8 100644
> --- a/newlib/libm/machine/arm/Makefile.in
> +++ b/newlib/libm/machine/arm/Makefile.in
> @@ -70,7 +70,8 @@ LIBRARIES = $(noinst_LIBRARIES)
> ARFLAGS = cru
> lib_a_AR = $(AR) $(ARFLAGS)
> lib_a_LIBADD =
> -am__objects_1 = lib_a-s_ceil.$(OBJEXT) lib_a-s_floor.$(OBJEXT) \
> +am__objects_1 = lib_a-e_sqrt.$(OBJEXT) lib_a-ef_sqrt.$(OBJEXT) \
> + lib_a-s_ceil.$(OBJEXT) lib_a-s_floor.$(OBJEXT) \
> lib_a-s_nearbyint.$(OBJEXT) lib_a-s_rint.$(OBJEXT) \
> lib_a-s_round.$(OBJEXT) lib_a-s_trunc.$(OBJEXT) \
> lib_a-sf_ceil.$(OBJEXT) lib_a-sf_floor.$(OBJEXT) \
> @@ -202,6 +203,8 @@ INCLUDES = -I $(newlib_basedir)/../newlib/libm/common $(NEWLIB_CFLAGS) \
> $(CROSS_CFLAGS) $(TARGET_CFLAGS)
>
> LIB_SOURCES = \
> + e_sqrt.c \
> + ef_sqrt.c \
> s_ceil.c \
> s_floor.c \
> s_nearbyint.c \
> @@ -291,6 +294,18 @@ distclean-compile:
> .c.obj:
> $(COMPILE) -c `$(CYGPATH_W) '$<'`
>
> +lib_a-e_sqrt.o: e_sqrt.c
> + $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-e_sqrt.o `test -f 'e_sqrt.c' || echo '$(srcdir)/'`e_sqrt.c
> +
> +lib_a-e_sqrt.obj: e_sqrt.c
> + $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-e_sqrt.obj `if test -f 'e_sqrt.c'; then $(CYGPATH_W) 'e_sqrt.c'; else $(CYGPATH_W) '$(srcdir)/e_sqrt.c'; fi`
> +
> +lib_a-ef_sqrt.o: ef_sqrt.c
> + $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-ef_sqrt.o `test -f 'ef_sqrt.c' || echo '$(srcdir)/'`ef_sqrt.c
> +
> +lib_a-ef_sqrt.obj: ef_sqrt.c
> + $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-ef_sqrt.obj `if test -f 'ef_sqrt.c'; then $(CYGPATH_W) 'ef_sqrt.c'; else $(CYGPATH_W) '$(srcdir)/ef_sqrt.c'; fi`
> +
> lib_a-s_ceil.o: s_ceil.c
> $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-s_ceil.o `test -f 's_ceil.c' || echo '$(srcdir)/'`s_ceil.c
>
> diff --git a/newlib/libm/machine/arm/e_sqrt.c b/newlib/libm/machine/arm/e_sqrt.c
> new file mode 100644
> index 0000000..8754b9f
> --- /dev/null
> +++ b/newlib/libm/machine/arm/e_sqrt.c
> @@ -0,0 +1,45 @@
> +/*-
> + * Copyright (c) 2017 embedded brains GmbH
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#if __ARM_FP & 0x8
> +#include <math.h>
> +
> +double
> +__ieee754_sqrt(double x)
> +{
> + double result;
> +#if __ARM_ARCH >= 6
> + asm ("vsqrt.f64 %P0, %P1" : "=w" (result) : "w" (x));
> +#else
> + /* VFP9 Erratum 760019, see GCC sources "gcc/config/arm/vfp.md" */
> + asm ("vsqrt.f64 %P0, %P1" : "=&w" (result) : "w" (x));
> +#endif
> + return result;
> +}
> +
> +#else
> +#include "../../math/e_sqrt.c"
> +#endif
> diff --git a/newlib/libm/machine/arm/ef_sqrt.c b/newlib/libm/machine/arm/ef_sqrt.c
> new file mode 100644
> index 0000000..81c29f1
> --- /dev/null
> +++ b/newlib/libm/machine/arm/ef_sqrt.c
> @@ -0,0 +1,45 @@
> +/*-
> + * Copyright (c) 2017 embedded brains GmbH
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#if __ARM_FP & 0x4
> +#include <math.h>
> +
> +float
> +__ieee754_sqrtf(float x)
> +{
> + float result;
> +#if __ARM_ARCH >= 6
> + asm ("vsqrt.f32 %0, %1" : "=w" (result) : "w" (x));
> +#else
> + /* VFP9 Erratum 760019, see GCC sources "gcc/config/arm/vfp.md" */
> + asm ("vsqrt.f32 %0, %1" : "=&w" (result) : "w" (x));
> +#endif
> + return result;
> +}
> +
> +#else
> +#include "../../math/ef_sqrt.c"
> +#endif
>
next prev parent reply other threads:[~2017-03-21 10:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 7:49 Sebastian Huber
2017-03-21 7:54 ` Sebastian Huber
2017-03-21 10:08 ` Richard Earnshaw (lists) [this message]
2017-03-21 13:43 ` Corinna Vinschen
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