Make mantissa type of mp_no configurable

The mantissa of mp_no is intended to take only integral values.  This
is a relatively good choice for powerpc due to its 4 fpus, but not for
other architectures, which suffer due to this choice.  This change
makes the default mantissa a long integer and allows powerpc to
override it.  Additionally, some operations have been optimized for
integer manipulation, resulting in a significant improvement in
performance.

1 files changed, 56 insertions, 0 deletions

diff --git a/sysdeps/powerpc/power4/fpu/mpa-arch.h b/sysdeps/powerpc/power4/fpu/mpa-arch.h
new file mode 100644
index 0000000000..9007c9d0ca
--- /dev/null
+++ b/sysdeps/powerpc/power4/fpu/mpa-arch.h
@@ -0,0 +1,56 @@
+/* Overridable constants and operations.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   This program 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.
+
+   This program 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 this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+typedef double mantissa_t;
+typedef double mantissa_store_t;
+
+#define TWOPOW(i) (0x1.0p##i)
+
+#define RADIX TWOPOW (24)		/* 2^24    */
+#define CUTTER TWOPOW (76)		/* 2^76    */
+#define RADIXI 0x1.0p-24		/* 2^-24 */
+#define TWO52 TWOPOW (52)		/* 2^52 */
+
+/* Divide D by RADIX and put the remainder in R.  */
+#define DIV_RADIX(d,r) \
+  ({									      \
+    double u = ((d) + CUTTER) - CUTTER;					      \
+    if (u > (d))							      \
+      u -= RADIX;							      \
+    r = (d) - u;							      \
+    (d) = u * RADIXI;							      \
+  })
+
+/* Put the integer component of a double X in R and retain the fraction in
+   X.  */
+#define INTEGER_OF(x, r) \
+  ({									      \
+    double u = ((x) + TWO52) - TWO52;					      \
+    if (u > (x))							      \
+      u -= ONE;								      \
+    (r) = u;								      \
+    (x) -= u;								      \
+  })
+
+/* Align IN down to a multiple of F, where F is a power of two.  */
+#define ALIGN_DOWN_TO(in, f) \
+  ({									      \
+    double factor = f * TWO52;						      \
+    double u = (in + factor) - factor;					      \
+    if (u > in)								      \
+      u -= f;								      \
+    u;									      \
+  })