mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
79 lines
2.1 KiB
C
79 lines
2.1 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_set_round_ui(arf_t x, ulong v, int sgnbit, long prec, arf_rnd_t rnd)
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{
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if (v == 0)
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{
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arf_zero(x);
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return 0;
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}
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else
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{
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unsigned int bc, mask_bits;
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int inexact;
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mp_limb_t t;
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count_leading_zeros(bc, v);
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v <<= bc;
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bc = FLINT_BITS - bc;
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if (prec >= bc)
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{
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inexact = 0;
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}
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else
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{
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mask_bits = FLINT_BITS - prec;
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t = v;
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v = (v >> mask_bits) << mask_bits;
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inexact = (t != v);
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if (inexact && arf_rounds_up(rnd, sgnbit))
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{
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v += (LIMB_ONE << (FLINT_BITS - prec));
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/* Overflow to the next power of two (unlikely). */
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if (v == 0)
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{
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v = LIMB_TOP;
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bc++;
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}
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}
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}
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fmpz_set_ui(ARF_EXPREF(x), bc);
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ARF_DEMOTE(x);
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ARF_XSIZE(x) = ARF_MAKE_XSIZE(1, sgnbit);
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ARF_NOPTR_D(x)[0] = v;
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return inexact;
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}
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}
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