efee5258bc
The MPFR library is a C library for multiple-precision floating-point computations with exact rounding (also called correct rounding). It is based on the GMP multiple-precision library and should replace the MPF class in further releases of GMP. GCC >= 4.2 requires MPFR.
95 lines
2.7 KiB
C
95 lines
2.7 KiB
C
/* mpfr_cmpabs -- compare the absolute values of two FP numbers
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Copyright 1999, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
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Contributed by the Arenaire and Cacao projects, INRIA.
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This file is part of the GNU MPFR Library.
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The GNU MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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The GNU MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
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http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
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#include "mpfr-impl.h"
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/* Return a positive value if abs(b) > abs(c), 0 if abs(b) = abs(c), and
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a negative value if abs(b) < abs(c). Neither b nor c may be NaN. */
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int
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mpfr_cmpabs (mpfr_srcptr b, mpfr_srcptr c)
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{
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mpfr_exp_t be, ce;
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mp_size_t bn, cn;
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mp_limb_t *bp, *cp;
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if (MPFR_ARE_SINGULAR (b, c))
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{
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if (MPFR_IS_NAN (b) || MPFR_IS_NAN (c))
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{
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MPFR_SET_ERANGE ();
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return 0;
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}
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else if (MPFR_IS_INF (b))
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return ! MPFR_IS_INF (c);
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else if (MPFR_IS_INF (c))
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return -1;
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else if (MPFR_IS_ZERO (c))
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return ! MPFR_IS_ZERO (b);
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else /* b == 0 */
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return -1;
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}
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MPFR_ASSERTD (MPFR_IS_PURE_FP (b));
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MPFR_ASSERTD (MPFR_IS_PURE_FP (c));
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/* Now that we know that b and c are pure FP numbers (i.e. they have
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a meaningful exponent), we use MPFR_EXP instead of MPFR_GET_EXP to
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allow exponents outside the current exponent range. For instance,
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this is useful for mpfr_pow, which compares values to __gmpfr_one.
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This is for internal use only! For compatibility with other MPFR
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versions, the user must still provide values that are representable
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in the current exponent range. */
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be = MPFR_EXP (b);
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ce = MPFR_EXP (c);
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if (be > ce)
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return 1;
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if (be < ce)
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return -1;
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/* exponents are equal */
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bn = MPFR_LIMB_SIZE(b)-1;
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cn = MPFR_LIMB_SIZE(c)-1;
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bp = MPFR_MANT(b);
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cp = MPFR_MANT(c);
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for ( ; bn >= 0 && cn >= 0; bn--, cn--)
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{
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if (bp[bn] > cp[cn])
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return 1;
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if (bp[bn] < cp[cn])
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return -1;
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}
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for ( ; bn >= 0; bn--)
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if (bp[bn])
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return 1;
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for ( ; cn >= 0; cn--)
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if (cp[cn])
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return -1;
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return 0;
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}
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