122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/* mpz_cmpabs_d -- compare absolute values of mpz and double.
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Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP 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 2.1 of the License, or (at your
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option) any later version.
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The GNU MP 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 MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "config.h"
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#if HAVE_FLOAT_H
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#include <float.h> /* for DBL_MAX */
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#endif
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#include "gmp.h"
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#include "gmp-impl.h"
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#define RETURN_CMP(zl, dl) \
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do { \
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zlimb = (zl); \
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dlimb = (dl); \
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if (zlimb != dlimb) \
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return (zlimb >= dlimb ? 1 : -1); \
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} while (0)
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#define RETURN_NONZERO(ptr, size, val) \
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do { \
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mp_size_t __i; \
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for (__i = (size)-1; __i >= 0; __i--) \
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if ((ptr)[__i] != 0) \
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return val; \
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return 0; \
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} while (0)
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int
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mpz_cmpabs_d (mpz_srcptr z, double d)
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{
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mp_limb_t darray[LIMBS_PER_DOUBLE], zlimb, dlimb;
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mp_srcptr zp;
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mp_size_t zsize;
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int dexp;
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/* d=NaN is an invalid operation, there's no sensible return value.
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d=Inf or -Inf is always bigger than z. */
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DOUBLE_NAN_INF_ACTION (d, __gmp_invalid_operation (), return -1);
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/* 1. Check for either operand zero. */
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zsize = SIZ(z);
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if (d == 0.0)
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return (zsize != 0);
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if (zsize == 0)
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return (d != 0 ? -1 : 0);
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/* 2. Ignore signs. */
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zsize = ABS(zsize);
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d = ABS(d);
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/* 3. Small d, knowing abs(z) >= 1. */
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if (d < 1.0)
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return 1;
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dexp = __gmp_extract_double (darray, d);
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ASSERT (dexp >= 1);
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/* 4. Check for different high limb positions. */
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if (zsize != dexp)
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return (zsize >= dexp ? 1 : -1);
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/* 5. Limb data. */
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zp = PTR(z);
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#if LIMBS_PER_DOUBLE == 2
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RETURN_CMP (zp[zsize-1], darray[1]);
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if (zsize == 1)
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return (darray[0] != 0 ? -1 : 0);
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RETURN_CMP (zp[zsize-2], darray[0]);
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RETURN_NONZERO (zp, zsize-2, 1);
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#endif
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#if LIMBS_PER_DOUBLE == 3
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RETURN_CMP (zp[zsize-1], darray[2]);
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if (zsize == 1)
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return ((darray[0] | darray[1]) != 0 ? -1 : 0);
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RETURN_CMP (zp[zsize-2], darray[1]);
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if (zsize == 2)
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return (darray[0] != 0 ? -1 : 0);
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RETURN_CMP (zp[zsize-3], darray[0]);
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RETURN_NONZERO (zp, zsize-3, 1);
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#endif
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#if LIMBS_PER_DOUBLE >= 4
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{
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int i;
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for (i = 1; i <= LIMBS_PER_DOUBLE; i++)
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{
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RETURN_CMP (zp[zsize-i], darray[LIMBS_PER_DOUBLE-i]);
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if (i >= zsize)
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RETURN_NONZERO (darray, LIMBS_PER_DOUBLE-i, -1);
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}
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RETURN_NONZERO (zp, zsize-LIMBS_PER_DOUBLE, 1);
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}
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#endif
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}
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