mirror of
https://github.com/vale981/arb
synced 2025-03-04 17:01:40 -05:00
52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
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/*
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Copyright (C) 2017 Fredrik Johansson
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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 it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "mag.h"
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void
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mag_div_lower(mag_t z, const mag_t x, const mag_t y)
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{
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if (mag_is_special(x) || mag_is_special(y))
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{
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if (mag_is_inf(x) && !mag_is_inf(y))
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mag_inf(z);
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else
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mag_zero(z);
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}
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else
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{
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mp_limb_t q;
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slong fix;
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#if FLINT_BITS == 64
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q = (MAG_MAN(x) << MAG_BITS) / MAG_MAN(y);
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#else
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mp_limb_t hi, lo, r;
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lo = MAG_MAN(x) << MAG_BITS;
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hi = MAG_MAN(x) >> (FLINT_BITS - MAG_BITS);
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udiv_qrnnd(q, r, hi, lo, MAG_MAN(y));
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#endif
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fix = q >> MAG_BITS;
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q = q >> fix;
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/* could overflow to next power of two */
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if (q >> MAG_BITS)
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{
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q >>= 1;
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fix += 1;
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}
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MAG_MAN(z) = q;
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_fmpz_sub2_fast(MAG_EXPREF(z), MAG_EXPREF(x), MAG_EXPREF(y), fix);
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}
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}
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