mirror of https://github.com/macssh/macssh.git
150 lines
3.4 KiB
C
Executable File
150 lines
3.4 KiB
C
Executable File
/* mpf_set_q (mpf_t rop, mpq_t op) -- Convert the rational op to the float rop.
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Copyright (C) 1996, 1999 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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#include "gmp.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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void
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#if __STDC__
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mpf_set_q (mpf_t r, mpq_srcptr q)
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#else
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mpf_set_q (r, q)
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mpf_t r;
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mpq_srcptr q;
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#endif
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{
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mp_ptr np, dp;
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mp_ptr rp;
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mp_size_t nsize, dsize;
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mp_size_t qsize, rsize;
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mp_size_t sign_quotient;
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unsigned normalization_steps;
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mp_limb_t qlimb;
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mp_ptr qp;
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mp_size_t prec;
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mp_exp_t exp;
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TMP_DECL (marker);
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nsize = SIZ (&q->_mp_num);
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dsize = SIZ (&q->_mp_den);
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if (nsize == 0)
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{
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SIZ (r) = 0;
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EXP (r) = 0;
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return;
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}
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prec = PREC (r) + 1;
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TMP_MARK (marker);
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qp = PTR (r);
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sign_quotient = nsize ^ dsize;
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nsize = ABS (nsize);
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dsize = ABS (dsize);
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np = PTR (&q->_mp_num);
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dp = PTR (&q->_mp_den);
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exp = nsize - dsize;
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if (nsize > prec)
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{
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np += nsize - prec;
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nsize = prec;
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}
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if (dsize > prec)
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{
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dp += dsize - prec;
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dsize = prec;
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}
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rsize = MAX (nsize, dsize);
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rp = (mp_ptr) TMP_ALLOC ((rsize + 1) * BYTES_PER_MP_LIMB);
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count_leading_zeros (normalization_steps, dp[dsize - 1]);
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/* Normalize the denominator, i.e. make its most significant bit set by
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shifting it NORMALIZATION_STEPS bits to the left. Also shift the
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numerator the same number of steps (to keep the quotient the same!). */
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if (normalization_steps != 0)
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{
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mp_ptr tp;
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mp_limb_t nlimb;
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/* Shift up the denominator setting the most significant bit of
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the most significant limb. Use temporary storage not to clobber
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the original contents of the denominator. */
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tp = (mp_ptr) TMP_ALLOC (dsize * BYTES_PER_MP_LIMB);
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mpn_lshift (tp, dp, dsize, normalization_steps);
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dp = tp;
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if (rsize != nsize)
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{
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MPN_ZERO (rp, rsize - nsize);
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nlimb = mpn_lshift (rp + (rsize - nsize),
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np, nsize, normalization_steps);
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}
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else
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{
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nlimb = mpn_lshift (rp, np, rsize, normalization_steps);
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}
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if (nlimb != 0)
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{
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rp[rsize] = nlimb;
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exp++;
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/* Don't just increase rsize, chop off rp at the low end instead. */
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if (rsize == prec)
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rp++;
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else
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rsize++;
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}
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}
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else
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{
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if (rsize != nsize)
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{
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MPN_ZERO (rp, rsize - nsize);
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MPN_COPY (rp + (rsize - nsize), np, nsize);
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}
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else
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{
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MPN_COPY (rp, np, rsize);
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}
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}
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qlimb = mpn_divrem (qp, prec - 1 - (rsize - dsize), rp, rsize, dp, dsize);
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qsize = prec - 1;
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if (qlimb)
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{
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qp[qsize] = qlimb;
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qsize++;
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exp++;
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}
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EXP (r) = exp;
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SIZ (r) = sign_quotient >= 0 ? qsize : -qsize;
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TMP_FREE (marker);
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}
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