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/* mpfr_cmp -- compare two floating-point numbers
Copyright (C) 1999, 2001 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"
/* returns 0 iff b = sign(s) * c
a positive value iff b > sign(s) * c
a negative value iff b < sign(s) * c
*/
int
mpfr_cmp3 (mpfr_srcptr b, mpfr_srcptr c, int s)
{
mp_exp_t be, ce;
mp_size_t bn, cn;
mp_limb_t *bp, *cp;
MPFR_ASSERTN(!MPFR_IS_NAN(b));
MPFR_ASSERTN(!MPFR_IS_NAN(c));
s *= MPFR_SIGN(c);
if (MPFR_IS_INF(b))
return (MPFR_IS_INF(c) && s * MPFR_SIGN(b) > 0) ? 0 : MPFR_SIGN(b);
if (MPFR_IS_INF(c))
return -s;
/* b and c are real numbers */
if (MPFR_IS_ZERO(b))
return MPFR_IS_ZERO(c) ? 0 : -s;
if (MPFR_IS_ZERO(c))
return MPFR_SIGN(b);
if (s * MPFR_SIGN(b) < 0)
return MPFR_SIGN(b);
/* now signs are equal */
be = MPFR_EXP(b);
ce = MPFR_EXP(c);
if (be > ce)
return s;
if (be < ce)
return -s;
/* both signs and exponents are equal */
bn = (MPFR_PREC(b)-1)/BITS_PER_MP_LIMB;
cn = (MPFR_PREC(c)-1)/BITS_PER_MP_LIMB;
bp = MPFR_MANT(b);
cp = MPFR_MANT(c);
for ( ; bn >= 0 && cn >= 0; bn--, cn--)
{
if (bp[bn] > cp[cn])
return s;
if (bp[bn] < cp[cn])
return -s;
}
for ( ; bn >= 0; bn--)
if (bp[bn])
return s;
for ( ; cn >= 0; cn--)
if (cp[cn])
return -s;
return 0;
}
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