--- /dev/null
+/* mpfr_powerof2_raw -- test whether a floating-point number is a power of 2
+
+Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+Contributed by the Arenaire and Cacao projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LIB. If not, write to
+the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+MA 02110-1301, USA. */
+
+#include "mpfr-impl.h"
+
+/* This is an internal function and one assumes that x is a real number. */
+
+int
+mpfr_powerof2_raw (mpfr_srcptr x)
+{
+ mp_limb_t *xp;
+ mp_size_t xn;
+
+ /* This is an internal function, and we may call it with some
+ wrong numbers (ie good mantissa but wrong flags or exp)
+ So we don't want to test if it is a pure FP.
+ MPFR_ASSERTN(MPFR_IS_PURE_FP(x)); */
+ xp = MPFR_MANT(x);
+ xn = (MPFR_PREC(x) - 1) / BITS_PER_MP_LIMB;
+ /*if (NOT_POW2(xp[xn]))*/
+ if (xp[xn] != MPFR_LIMB_HIGHBIT)
+ return 0;
+ while (xn > 0)
+ if (xp[--xn] != 0)
+ return 0;
+ return 1;
+}