76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
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/* mpf_sqrt -- Compute the square root of a float.
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Copyright (C) 1993, 1994, 1996 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 Library General Public License as published by
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the Free Software Foundation; either version 2 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 Library General Public
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License for more details.
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You should have received a copy of the GNU Library 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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#include "gmp.h"
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#include "gmp-impl.h"
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void
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#if __STDC__
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mpf_sqrt (mpf_ptr r, mpf_srcptr u)
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#else
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mpf_sqrt (r, u)
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mpf_ptr r;
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mpf_srcptr u;
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#endif
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{
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mp_size_t usize;
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mp_ptr up, tp;
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mp_size_t prec;
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mp_exp_t tsize, rexp;
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TMP_DECL (marker);
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usize = u->_mp_size;
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if (usize <= 0)
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{
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usize = 1 - 1 / (usize == 0); /* Divide by zero for negative OP. */
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r->_mp_size = usize; /* cheat flow by using usize here */
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r->_mp_exp = 0;
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return;
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}
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TMP_MARK (marker);
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prec = r->_mp_prec;
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rexp = (u->_mp_exp + 1) >> 1; /* round towards -inf */
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tsize = 2 * prec + (u->_mp_exp & 1);
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up = u->_mp_d;
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tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
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if (usize > tsize)
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{
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up += usize - tsize;
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usize = tsize;
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MPN_COPY (tp, up, tsize);
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}
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else
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{
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MPN_ZERO (tp, tsize - usize);
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MPN_COPY (tp + (tsize - usize), up, usize);
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}
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mpn_sqrtrem (r->_mp_d, NULL, tp, tsize);
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r->_mp_size = (tsize + 1) / 2;
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r->_mp_exp = rexp;
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TMP_FREE (marker);
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}
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