mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
82 lines
2.2 KiB
C
82 lines
2.2 KiB
C
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/*=============================================================================
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This file is part of ARB.
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ARB is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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ARB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with ARB; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2014 Fredrik Johansson
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******************************************************************************/
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#include "arf.h"
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int
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_arf_get_integer_mpn(mp_ptr y, mp_srcptr x, mp_size_t xn, slong exp)
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{
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slong bot_exp = exp - xn * FLINT_BITS;
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if (bot_exp >= 0)
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{
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mp_size_t bot_limbs;
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mp_bitcnt_t bot_bits;
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bot_limbs = bot_exp / FLINT_BITS;
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bot_bits = bot_exp % FLINT_BITS;
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flint_mpn_zero(y, bot_limbs);
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if (bot_bits == 0)
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flint_mpn_copyi(y + bot_limbs, x, xn);
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else
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y[bot_limbs + xn] = mpn_lshift(y + bot_limbs, x, xn, bot_bits);
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/* exact */
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return 0;
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}
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else if (exp <= 0)
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{
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/* inexact */
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return 1;
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}
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else
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{
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mp_size_t top_limbs;
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mp_bitcnt_t top_bits;
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mp_limb_t cy;
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top_limbs = exp / FLINT_BITS;
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top_bits = exp % FLINT_BITS;
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if (top_bits == 0)
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{
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flint_mpn_copyi(y, x + xn - top_limbs, top_limbs);
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/* inexact */
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return 1;
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}
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else
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{
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/* can be inexact */
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cy = mpn_rshift(y, x + xn - top_limbs - 1,
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top_limbs + 1, FLINT_BITS - top_bits);
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return (cy != 0) || (top_limbs + 1 != xn);
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}
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}
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}
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