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[PATCH] PowerPC: modf optimization
- From: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- To: "GNU C. Library" <libc-alpha at sourceware dot org>
- Date: Mon, 25 Mar 2013 14:43:04 -0300
- Subject: [PATCH] PowerPC: modf optimization
This patch implements modf/modff optimization for POWER by focus
on FP operations instead of relying in integer ones.
For POWER7 it shows a leverage of about 50% for modf ppc32, 40% for
modff ppc32, 65% for modf ppc64, and 60% for modff ppc64.
Any though, tips, advices?
---
2013-03-25 Adhemerval Zanella <azanella@linux.vnet.ibm.com>
* sysdeps/powerpc/fpu/s_modf.c: New file: modf optimization for POWER.
* sysdeps/powerpc/fpu/s_modff.c: New file: modff optimization for POWER.
* sysdeps/powerpc/fpu/Makefile: Add s_floor[f] and s_ceil[f] for
powerpc64/POWER4 builds.
diff --git a/sysdeps/powerpc/fpu/Makefile b/sysdeps/powerpc/fpu/Makefile
index fda59f9..fe1eadc 100644
--- a/sysdeps/powerpc/fpu/Makefile
+++ b/sysdeps/powerpc/fpu/Makefile
@@ -1,6 +1,8 @@
ifeq ($(subdir),math)
libm-support += fenv_const fe_nomask fe_mask t_sqrt
+# modf needs floof and ceil for powerpc64/POWER4
+sysdep_routines += s_floor s_ceil s_floorf s_ceilf
# libm needs ld.so to access dl_hwcap
$(objpfx)libm.so: $(elfobjdir)/ld.so
endif
diff --git a/sysdeps/powerpc/fpu/s_modf.c b/sysdeps/powerpc/fpu/s_modf.c
new file mode 100644
index 0000000..b45bf66
--- /dev/null
+++ b/sysdeps/powerpc/fpu/s_modf.c
@@ -0,0 +1,58 @@
+/* Copyright (C) 2013 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <math_private.h>
+#include <math_ldbl_opt.h>
+
+double
+__modf (double x, double *iptr)
+{
+ if (__builtin_isinf (x))
+ {
+ *iptr = x;
+ return __copysign (0.0, x);
+ }
+ else if (__builtin_isnan (x))
+ {
+ *iptr = NAN;
+ return NAN;
+ }
+
+ if (x >= 0.0)
+ {
+ *iptr = __floor (x);
+ return (x - *iptr);
+ }
+ else
+ {
+ *iptr = __ceil (x);
+ return (x - *iptr);
+ }
+}
+weak_alias (__modf, modf)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__modf, __modfl)
+weak_alias (__modf, modfl)
+#endif
+#ifdef IS_IN_libm
+# if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
+compat_symbol (libm, __modf, modfl, GLIBC_2_0);
+# endif
+#elif LONG_DOUBLE_COMPAT(libc, GLIBC_2_0)
+compat_symbol (libc, __modf, modfl, GLIBC_2_0);
+#endif
diff --git a/sysdeps/powerpc/fpu/s_modff.c b/sysdeps/powerpc/fpu/s_modff.c
new file mode 100644
index 0000000..55759cd
--- /dev/null
+++ b/sysdeps/powerpc/fpu/s_modff.c
@@ -0,0 +1,46 @@
+/* Copyright (C) 2013 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <math_private.h>
+
+float
+__modff (float x, float *iptr)
+{
+ if (__builtin_isinff (x))
+ {
+ *iptr = x;
+ return __copysignf (0.0, x);
+ }
+ else if (__builtin_isnanf (x))
+ {
+ *iptr = NAN;
+ return NAN;
+ }
+
+ if (x >= 0.0)
+ {
+ *iptr = __floorf (x);
+ return (x - *iptr);
+ }
+ else
+ {
+ *iptr = __ceilf (x);
+ return (x - *iptr);
+ }
+}
+weak_alias (__modff, modff)