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/* mpfr_powerof2_raw -- test whether a floating-point number is a power of 2
Copyright 2002 Free Software Foundation.
This file is part of the MPFR Library.
The 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 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 MPFR Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include "mpfr.h"
#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;
MPFR_ASSERTN(MPFR_IS_FP(x));
xp = MPFR_MANT(x);
xn = (MPFR_PREC(x) - 1) / BITS_PER_MP_LIMB;
if (NOT_POW2(xp[xn]))
return 0;
while (xn > 0)
if (xp[--xn] != 0)
return 0;
return 1;
}
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