cmpabs_d.c
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上传日期:2022-08-06
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- /* mpz_cmpabs_d -- compare absolute values of mpz and double.
- Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
- This file is part of the GNU MP Library.
- The GNU MP 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 MP 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 MP Library. If not, see http://www.gnu.org/licenses/. */
- #include "config.h"
- #if HAVE_FLOAT_H
- #include <float.h> /* for DBL_MAX */
- #endif
- #include "gmp.h"
- #include "gmp-impl.h"
- #define RETURN_CMP(zl, dl)
- do {
- zlimb = (zl);
- dlimb = (dl);
- if (zlimb != dlimb)
- return (zlimb >= dlimb ? 1 : -1);
- } while (0)
- #define RETURN_NONZERO(ptr, size, val)
- do {
- mp_size_t __i;
- for (__i = (size)-1; __i >= 0; __i--)
- if ((ptr)[__i] != 0)
- return val;
- return 0;
- } while (0)
- int
- mpz_cmpabs_d (mpz_srcptr z, double d)
- {
- mp_limb_t darray[LIMBS_PER_DOUBLE], zlimb, dlimb;
- mp_srcptr zp;
- mp_size_t zsize;
- int dexp;
- /* d=NaN is an invalid operation, there's no sensible return value.
- d=Inf or -Inf is always bigger than z. */
- DOUBLE_NAN_INF_ACTION (d, __gmp_invalid_operation (), return -1);
- /* 1. Check for either operand zero. */
- zsize = SIZ(z);
- if (d == 0.0)
- return (zsize != 0);
- if (zsize == 0)
- return (d != 0 ? -1 : 0);
- /* 2. Ignore signs. */
- zsize = ABS(zsize);
- d = ABS(d);
- /* 3. Small d, knowing abs(z) >= 1. */
- if (d < 1.0)
- return 1;
- dexp = __gmp_extract_double (darray, d);
- ASSERT (dexp >= 1);
- /* 4. Check for different high limb positions. */
- if (zsize != dexp)
- return (zsize >= dexp ? 1 : -1);
- /* 5. Limb data. */
- zp = PTR(z);
- #if LIMBS_PER_DOUBLE == 2
- RETURN_CMP (zp[zsize-1], darray[1]);
- if (zsize == 1)
- return (darray[0] != 0 ? -1 : 0);
- RETURN_CMP (zp[zsize-2], darray[0]);
- RETURN_NONZERO (zp, zsize-2, 1);
- #endif
- #if LIMBS_PER_DOUBLE == 3
- RETURN_CMP (zp[zsize-1], darray[2]);
- if (zsize == 1)
- return ((darray[0] | darray[1]) != 0 ? -1 : 0);
- RETURN_CMP (zp[zsize-2], darray[1]);
- if (zsize == 2)
- return (darray[0] != 0 ? -1 : 0);
- RETURN_CMP (zp[zsize-3], darray[0]);
- RETURN_NONZERO (zp, zsize-3, 1);
- #endif
- #if LIMBS_PER_DOUBLE >= 4
- {
- int i;
- for (i = 1; i <= LIMBS_PER_DOUBLE; i++)
- {
- RETURN_CMP (zp[zsize-i], darray[LIMBS_PER_DOUBLE-i]);
- if (i >= zsize)
- RETURN_NONZERO (darray, LIMBS_PER_DOUBLE-i, -1);
- }
- RETURN_NONZERO (zp, zsize-LIMBS_PER_DOUBLE, 1);
- }
- #endif
- }