51c586b89d
GNU MP is a library for arbitrary precision arithmetic, operating on signed integers, rational numbers, and floating point numbers. It has a rich set of functions, and the functions have a regular interface. GMP is necessary for GCC >= 4.2.
86 lines
2.0 KiB
C
86 lines
2.0 KiB
C
/* mpf_mul -- Multiply two floats.
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Copyright 1993, 1994, 1996, 2001, 2005 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 3 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. If not, see http://www.gnu.org/licenses/. */
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#include "gmp.h"
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#include "gmp-impl.h"
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void
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mpf_mul (mpf_ptr r, mpf_srcptr u, mpf_srcptr v)
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{
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mp_srcptr up, vp;
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mp_size_t usize, vsize;
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mp_size_t sign_product;
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mp_size_t prec = r->_mp_prec;
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TMP_DECL;
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TMP_MARK;
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usize = u->_mp_size;
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vsize = v->_mp_size;
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sign_product = usize ^ vsize;
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usize = ABS (usize);
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vsize = ABS (vsize);
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up = u->_mp_d;
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vp = v->_mp_d;
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if (usize > prec)
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{
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up += usize - prec;
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usize = prec;
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}
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if (vsize > prec)
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{
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vp += vsize - prec;
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vsize = prec;
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}
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if (usize == 0 || vsize == 0)
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{
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r->_mp_size = 0;
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r->_mp_exp = 0; /* ??? */
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}
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else
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{
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mp_size_t rsize;
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mp_limb_t cy_limb;
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mp_ptr rp, tp;
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mp_size_t adj;
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rsize = usize + vsize;
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tp = TMP_ALLOC_LIMBS (rsize);
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cy_limb = (usize >= vsize
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? mpn_mul (tp, up, usize, vp, vsize)
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: mpn_mul (tp, vp, vsize, up, usize));
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adj = cy_limb == 0;
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rsize -= adj;
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prec++;
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if (rsize > prec)
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{
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tp += rsize - prec;
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rsize = prec;
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}
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rp = r->_mp_d;
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MPN_COPY (rp, tp, rsize);
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r->_mp_exp = u->_mp_exp + v->_mp_exp - adj;
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r->_mp_size = sign_product >= 0 ? rsize : -rsize;
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}
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TMP_FREE;
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}
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