libm/machine/arm: Add optimized fmaf and fma when available

When HAVE_FAST_FMAF is set, use the vfma.f32 instruction, when
HAVE_FAST_FMA is set, use the vfma.f64 instruction.

Usually the compiler built-ins will already have inlined these
instructions, but provide these symbols for cases where that doesn't
work instead of falling back to the (inaccurate) common code versions.

Signed-off-by: Keith Packard <keithp@keithp.com>

newlib/libm/common/s_fma.c

@@ -38,6 +38,8 @@ ANSI C, POSIX.
 
 #include "fdlibm.h"
 
+#if !HAVE_FAST_FMA
+
 #ifndef _DOUBLE_IS_32BITS
 
 #ifdef __STDC__
@@ -54,3 +56,5 @@ ANSI C, POSIX.
 }
 
 #endif /* _DOUBLE_IS_32BITS */
+
+#endif /* !HAVE_FAST_FMA */

newlib/libm/common/sf_fma.c

@@ -6,6 +6,8 @@
 
 #include "fdlibm.h"
 
+#if !HAVE_FAST_FMAF
+
 #ifdef __STDC__
 	float fmaf(float x, float y, float z)
 #else
@@ -25,6 +27,8 @@
   return (float) (((double) x * (double) y) + (double) z);
 }
 
+#endif
+
 #ifdef _DOUBLE_IS_32BITS
 
 #ifdef __STDC__

newlib/libm/machine/arm/Makefile.am

@@ -10,12 +10,14 @@ LIB_SOURCES = \
 	ef_sqrt.c \
 	s_ceil.c \
 	s_floor.c \
+	s_fma.c \
 	s_nearbyint.c \
 	s_rint.c \
 	s_round.c \
 	s_trunc.c \
 	sf_ceil.c \
 	sf_floor.c \
+	sf_fma.c \
 	sf_nearbyint.c \
 	sf_rint.c \
 	sf_round.c \

newlib/libm/machine/arm/Makefile.in

@@ -54,8 +54,7 @@ build_triplet = @build@
 host_triplet = @host@
 DIST_COMMON = $(srcdir)/../../../Makefile.shared $(srcdir)/Makefile.in \
 	$(srcdir)/Makefile.am $(top_srcdir)/configure \
-	$(am__configure_deps) $(srcdir)/../../../../mkinstalldirs \
+	$(am__configure_deps) $(srcdir)/../../../../mkinstalldirs
-	$(srcdir)/../../../../mkinstalldirs
 subdir = .
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/../../../acinclude.m4 \
@@ -73,9 +72,10 @@ lib_a_AR = $(AR) $(ARFLAGS)
 lib_a_LIBADD =
 am__objects_1 = lib_a-e_sqrt.$(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.$(OBJEXT) \
+	lib_a-s_fma.$(OBJEXT) lib_a-s_nearbyint.$(OBJEXT) \
-	lib_a-s_round.$(OBJEXT) lib_a-s_trunc.$(OBJEXT) \
+	lib_a-s_rint.$(OBJEXT) lib_a-s_round.$(OBJEXT) \
-	lib_a-sf_ceil.$(OBJEXT) lib_a-sf_floor.$(OBJEXT) \
+	lib_a-s_trunc.$(OBJEXT) lib_a-sf_ceil.$(OBJEXT) \
+	lib_a-sf_floor.$(OBJEXT) lib_a-sf_fma.$(OBJEXT) \
 	lib_a-sf_nearbyint.$(OBJEXT) lib_a-sf_rint.$(OBJEXT) \
 	lib_a-sf_round.$(OBJEXT) lib_a-sf_trunc.$(OBJEXT) \
 	lib_a-feclearexcept.$(OBJEXT) lib_a-fe_dfl_env.$(OBJEXT) \
@@ -216,12 +216,14 @@ LIB_SOURCES = \
 	ef_sqrt.c \
 	s_ceil.c \
 	s_floor.c \
+	s_fma.c \
 	s_nearbyint.c \
 	s_rint.c \
 	s_round.c \
 	s_trunc.c \
 	sf_ceil.c \
 	sf_floor.c \
+	sf_fma.c \
 	sf_nearbyint.c \
 	sf_rint.c \
 	sf_round.c \
@@ -342,6 +344,12 @@ lib_a-s_floor.o: s_floor.c
 lib_a-s_floor.obj: s_floor.c
 	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-s_floor.obj `if test -f 's_floor.c'; then $(CYGPATH_W) 's_floor.c'; else $(CYGPATH_W) '$(srcdir)/s_floor.c'; fi`
 
+lib_a-s_fma.o: s_fma.c
+	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-s_fma.o `test -f 's_fma.c' || echo '$(srcdir)/'`s_fma.c
+
+lib_a-s_fma.obj: s_fma.c
+	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-s_fma.obj `if test -f 's_fma.c'; then $(CYGPATH_W) 's_fma.c'; else $(CYGPATH_W) '$(srcdir)/s_fma.c'; fi`
+
 lib_a-s_nearbyint.o: s_nearbyint.c
 	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-s_nearbyint.o `test -f 's_nearbyint.c' || echo '$(srcdir)/'`s_nearbyint.c
 
@@ -378,6 +386,12 @@ lib_a-sf_floor.o: sf_floor.c
 lib_a-sf_floor.obj: sf_floor.c
 	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-sf_floor.obj `if test -f 'sf_floor.c'; then $(CYGPATH_W) 'sf_floor.c'; else $(CYGPATH_W) '$(srcdir)/sf_floor.c'; fi`
 
+lib_a-sf_fma.o: sf_fma.c
+	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-sf_fma.o `test -f 'sf_fma.c' || echo '$(srcdir)/'`sf_fma.c
+
+lib_a-sf_fma.obj: sf_fma.c
+	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-sf_fma.obj `if test -f 'sf_fma.c'; then $(CYGPATH_W) 'sf_fma.c'; else $(CYGPATH_W) '$(srcdir)/sf_fma.c'; fi`
+
 lib_a-sf_nearbyint.o: sf_nearbyint.c
 	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-sf_nearbyint.o `test -f 'sf_nearbyint.c' || echo '$(srcdir)/'`sf_nearbyint.c
 

newlib/libm/machine/arm/s_fma.c

@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright © 2020 Keith Packard
+ *
+ * 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.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT HOLDER 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.
+ */
+
+#include <math.h>
+#include "math_config.h"
+
+#if HAVE_FAST_FMA
+
+double
+fma (double x, double y, double z)
+{
+  asm ("vfma.f64 %P0, %P1, %P2" : "=w" (z) : "w" (x), "w" (y));
+  return z;
+}
+
+#endif

newlib/libm/machine/arm/sf_fma.c

@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright © 2020 Keith Packard
+ *
+ * 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.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT HOLDER 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.
+ */
+
+#include <math.h>
+#include "math_config.h"
+
+#if HAVE_FAST_FMAF
+
+float
+fmaf (float x, float y, float z)
+{
+  asm ("vfma.f32 %0, %1, %2" : "=t" (z) : "t" (x), "t" (y));
+  return z;
+}
+
+#endif