mirror of https://github.com/macssh/macssh.git
140 lines
3.3 KiB
C
Executable File
140 lines
3.3 KiB
C
Executable File
/* mpq_set_d(mpq_t q, double d) -- Set q to d without rounding.
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Copyright (C) 2000 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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#if BITS_PER_MP_LIMB != 32 && BITS_PER_MP_LIMB != 64
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This file does not handle any the used BITS_PER_MP_LIMB.
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#endif
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void
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#if __STDC__
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mpq_set_d (mpq_ptr dest, double d)
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#else
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mpq_set_d (dest, d)
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mpq_ptr dest;
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double d;
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#endif
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{
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int negative;
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mp_exp_t exp;
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mp_limb_t tp[3];
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mp_ptr np, dp;
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mp_size_t nn, dn;
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int c;
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negative = d < 0;
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d = ABS (d);
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exp = __gmp_extract_double (tp, d);
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/* There are two main version of the conversion. The `then' arm handles
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things that have a fractional part, while the `else' part handles
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only integers. */
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#if BITS_PER_MP_LIMB == 32
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if (exp <= 1 || (exp == 2 && tp[0] != 0))
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#else
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if (exp <= 1)
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#endif
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{
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if (d == 0.0)
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{
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SIZ(&(dest->_mp_num)) = 0;
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SIZ(&(dest->_mp_den)) = 1;
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PTR(&(dest->_mp_den))[0] = 1;
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return;
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}
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dn = -exp;
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if (dest->_mp_num._mp_alloc < 3)
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_mpz_realloc (&(dest->_mp_num), 3);
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np = PTR(&(dest->_mp_num));
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#if BITS_PER_MP_LIMB == 32
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if ((tp[0] | tp[1]) == 0)
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np[0] = tp[2], nn = 1;
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else if (tp[0] == 0)
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np[1] = tp[2], np[0] = tp[1], nn = 2;
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else
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np[2] = tp[2], np[1] = tp[1], np[0] = tp[0], nn = 3;
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#else
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if (tp[0] == 0)
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np[0] = tp[1], nn = 1;
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else
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np[1] = tp[1], np[0] = tp[0], nn = 2;
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#endif
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dn += nn + 1;
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if (dest->_mp_den._mp_alloc < dn)
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_mpz_realloc (&(dest->_mp_den), dn);
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dp = PTR(&(dest->_mp_den));
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MPN_ZERO (dp, dn - 1);
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dp[dn - 1] = 1;
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count_trailing_zeros (c, np[0] | dp[0]);
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if (c != 0)
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{
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mpn_rshift (np, np, nn, c);
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nn -= np[nn - 1] == 0;
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mpn_rshift (dp, dp, dn, c);
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dn -= dp[dn - 1] == 0;
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}
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SIZ(&(dest->_mp_den)) = dn;
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SIZ(&(dest->_mp_num)) = negative ? -nn : nn;
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}
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else
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{
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nn = exp;
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if (dest->_mp_num._mp_alloc < nn)
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_mpz_realloc (&(dest->_mp_num), nn);
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np = PTR(&(dest->_mp_num));
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#if BITS_PER_MP_LIMB == 32
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switch (nn)
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{
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default:
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MPN_ZERO (np, nn - 3);
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np += nn - 3;
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/* fall through */
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case 3:
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np[2] = tp[2], np[1] = tp[1], np[0] = tp[0];
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break;
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case 2:
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np[1] = tp[2], np[0] = tp[1];
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break;
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}
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#else
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switch (nn)
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{
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default:
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MPN_ZERO (np, nn - 2);
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np += nn - 2;
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/* fall through */
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case 2:
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np[1] = tp[1], np[0] = tp[0];
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break;
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}
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#endif
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dp = PTR(&(dest->_mp_den));
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dp[0] = 1;
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SIZ(&(dest->_mp_den)) = 1;
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SIZ(&(dest->_mp_num)) = negative ? -nn : nn;
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}
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}
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