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/* mpf_div -- Divide two floats.
Copyright (C) 1993, 1994, 1996 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
void
#if __STDC__
mpf_div (mpf_ptr r, mpf_srcptr u, mpf_srcptr v)
#else
mpf_div (r, u, v)
mpf_ptr r;
mpf_srcptr u;
mpf_srcptr v;
#endif
{
mp_srcptr up, vp;
mp_ptr rp, tp, rtp;
mp_size_t usize, vsize;
mp_size_t rsize, tsize;
mp_size_t sign_quotient;
mp_size_t prec;
unsigned normalization_steps;
mp_limb_t q_limb;
mp_exp_t rexp;
TMP_DECL (marker);
usize = u->_mp_size;
vsize = v->_mp_size;
sign_quotient = usize ^ vsize;
usize = ABS (usize);
vsize = ABS (vsize);
prec = r->_mp_prec;
if (vsize == 0)
vsize = 1 / vsize; /* divide by zero as directed */
if (usize == 0)
{
r->_mp_size = 0;
r->_mp_exp = 0;
return;
}
TMP_MARK (marker);
rexp = u->_mp_exp - v->_mp_exp;
rp = r->_mp_d;
up = u->_mp_d;
vp = v->_mp_d;
if (vsize > prec)
{
vp += vsize - prec;
vsize = prec;
}
tsize = vsize + prec;
tp = (mp_ptr) TMP_ALLOC ((tsize + 1) * BYTES_PER_MP_LIMB);
if (usize > tsize)
{
up += usize - tsize;
usize = tsize;
rtp = tp;
}
else
{
MPN_ZERO (tp, tsize - usize);
rtp = tp + (tsize - usize);
}
count_leading_zeros (normalization_steps, vp[vsize - 1]);
/* Normalize the divisor and the dividend. */
if (normalization_steps != 0)
{
mp_ptr tmp;
mp_limb_t nlimb;
/* Shift up the divisor setting the most significant bit of
the most significant limb. Use temporary storage not to clobber
the original contents of the divisor. */
tmp = (mp_ptr) TMP_ALLOC (vsize * BYTES_PER_MP_LIMB);
mpn_lshift (tmp, vp, vsize, normalization_steps);
vp = tmp;
/* Shift up the dividend, possibly introducing a new most
significant word. Move the shifted dividend in the remainder
at the same time. */
nlimb = mpn_lshift (rtp, up, usize, normalization_steps);
if (nlimb != 0)
{
rtp[usize] = nlimb;
tsize++;
rexp++;
}
}
else
{
/* The divisor is already normalized, as required.
Copy it to temporary space if it overlaps with the quotient. */
if (vp - rp <= tsize - vsize)
{
mp_ptr tmp = (mp_ptr) TMP_ALLOC (vsize * BYTES_PER_MP_LIMB);
MPN_COPY (tmp, vp, vsize);
vp = (mp_srcptr) tmp;
}
/* Move the dividend to the remainder. */
MPN_COPY (rtp, up, usize);
}
q_limb = mpn_divmod (rp, tp, tsize, vp, vsize);
rsize = tsize - vsize;
if (q_limb)
{
rp[rsize] = q_limb;
rsize++;
rexp++;
}
r->_mp_size = sign_quotient >= 0 ? rsize : -rsize;
r->_mp_exp = rexp;
TMP_FREE (marker);
}
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