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/* mpfr_cmpabs -- compare the absolute values of two FP numbers
Copyright 1999, 2001-2004, 2006-2020 Free Software Foundation, Inc.
Contributed by the AriC and Caramba 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 3 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.LESSER. If not, see
https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#include "mpfr-impl.h"
/* Return a positive value if abs(b) > abs(c), 0 if abs(b) = abs(c), and
a negative value if abs(b) < abs(c). Neither b nor c may be NaN. */
int
mpfr_cmpabs (mpfr_srcptr b, mpfr_srcptr c)
{
mpfr_exp_t be, ce;
mp_size_t bn, cn;
mp_limb_t *bp, *cp;
if (MPFR_ARE_SINGULAR (b, c))
{
if (MPFR_IS_NAN (b) || MPFR_IS_NAN (c))
{
MPFR_SET_ERANGEFLAG ();
return 0;
}
else if (MPFR_IS_INF (b))
return ! MPFR_IS_INF (c);
else if (MPFR_IS_INF (c))
return -1;
else if (MPFR_IS_ZERO (c))
return ! MPFR_IS_ZERO (b);
else /* b == 0 */
return -1;
}
MPFR_ASSERTD (MPFR_IS_PURE_FP (b));
MPFR_ASSERTD (MPFR_IS_PURE_FP (c));
/* Now that we know that b and c are pure FP numbers (i.e. they have
a meaningful exponent), we use MPFR_EXP instead of MPFR_GET_EXP to
allow exponents outside the current exponent range. For instance,
this is useful for mpfr_pow, which compares values to __gmpfr_one.
This is for internal use only! For compatibility with other MPFR
versions, the user must still provide values that are representable
in the current exponent range. */
be = MPFR_EXP (b);
ce = MPFR_EXP (c);
if (be > ce)
return 1;
if (be < ce)
return -1;
/* exponents are equal */
bn = MPFR_LIMB_SIZE(b)-1;
cn = MPFR_LIMB_SIZE(c)-1;
bp = MPFR_MANT(b);
cp = MPFR_MANT(c);
for ( ; bn >= 0 && cn >= 0; bn--, cn--)
{
if (bp[bn] > cp[cn])
return 1;
if (bp[bn] < cp[cn])
return -1;
}
for ( ; bn >= 0; bn--)
if (bp[bn])
return 1;
for ( ; cn >= 0; cn--)
if (cp[cn])
return -1;
return 0;
}
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