get_d_2exp.c
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上传日期:2022-08-06
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- /* double mpf_get_d_2exp (signed long int *exp, mpf_t src).
- Copyright 2001, 2002, 2003, 2004 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 "gmp.h"
- #include "gmp-impl.h"
- #include "longlong.h"
- double
- mpf_get_d_2exp (signed long int *exp2, mpf_srcptr src)
- {
- mp_size_t size, abs_size;
- mp_srcptr ptr;
- int cnt;
- long exp;
- size = SIZ(src);
- if (UNLIKELY (size == 0))
- {
- *exp2 = 0;
- return 0.0;
- }
- ptr = PTR(src);
- abs_size = ABS (size);
- count_leading_zeros (cnt, ptr[abs_size - 1]);
- cnt -= GMP_NAIL_BITS;
- exp = EXP(src) * GMP_NUMB_BITS - cnt;
- *exp2 = exp;
- return mpn_get_d (ptr, abs_size, (mp_size_t) 0,
- (long) - (abs_size * GMP_NUMB_BITS - cnt));
- }