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/* double mpf_get_d_2exp (signed long int *exp, mpf_t src).
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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., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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mpf_get_d_2exp (signed long int *exp2, mpf_srcptr src)
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mp_size_t size, i, n_limbs_to_use;
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n_limbs_to_use = MIN (LIMBS_PER_DOUBLE, size);
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qp += size - n_limbs_to_use;
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res = qp[0] / MP_BASE_AS_DOUBLE;
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for (i = 1; i < n_limbs_to_use; i++)
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res = (res + qp[i]) / MP_BASE_AS_DOUBLE;
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count_leading_zeros (cnt, qp[n_limbs_to_use - 1]);
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*exp2 = EXP(src) * GMP_NUMB_BITS - cnt + GMP_NAIL_BITS;
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res = res * ((mp_limb_t) 1 << cnt);
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/* gcc on m68k and x86 holds floats in the coprocessor, which may mean
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"res" has extra precision. Force it through memory to ensure any
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rounding takes place now and won't become 1.0 in the caller. */
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#if (HAVE_HOST_CPU_FAMILY_m68k || HAVE_HOST_CPU_FAMILY_x86) \
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asm ("" : "=m" (res) : "0" (res));
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/* if hardware floats are in round upwards mode then res may be 1.0 */
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return negative ? -res : res;