void
mpf_ui_sub (mpf_ptr r, unsigned long int u, mpf_srcptr v)
{
#if 1
__mpf_struct uu;
mp_limb_t ul;
if (u == 0)
{
mpf_neg (r, v);
return;
}
ul = u;
uu._mp_size = 1;
uu._mp_d = &ul;
uu._mp_exp = 1;
mpf_sub (r, &uu, v);
#else
mp_srcptr up, vp;
mp_ptr rp, tp;
mp_size_t usize, vsize, rsize;
mp_size_t prec;
mp_exp_t uexp;
mp_size_t ediff;
int negate;
mp_limb_t ulimb;
TMP_DECL;
vsize = v->_mp_size;
/* Handle special cases that don't work in generic code below. */
if (u == 0)
{
mpf_neg (r, v);
return;
}
if (vsize == 0)
{
mpf_set_ui (r, u);
return;
}
/* If signs of U and V are different, perform addition. */
if (vsize < 0)
{
__mpf_struct v_negated;
v_negated._mp_size = -vsize;
v_negated._mp_exp = v->_mp_exp;
v_negated._mp_d = v->_mp_d;
mpf_add_ui (r, &v_negated, u);
return;
}
/* Signs are now known to be the same. */
ASSERT (vsize > 0);
ulimb = u;
/* Make U be the operand with the largest exponent. */
negate = 1 < v->_mp_exp;
prec = r->_mp_prec + negate;
rp = r->_mp_d;
if (negate)
{
usize = vsize;
vsize = 1;
up = v->_mp_d;
vp = &ulimb;
uexp = v->_mp_exp;
ediff = uexp - 1;
/* If U extends beyond PREC, ignore the part that does. */
if (usize > prec)
{
up += usize - prec;
usize = prec;
}
ASSERT (ediff > 0);
}
else
{
vp = v->_mp_d;
ediff = 1 - v->_mp_exp;
/* Ignore leading limbs in U and V that are equal. Doing
this helps increase the precision of the result. */
if (ediff == 0 && ulimb == vp[vsize - 1])
{
usize = 0;
vsize--;
uexp = 0;
/* Note that V might now have leading zero limbs.
In that case we have to adjust uexp. */
for (;;)
{
if (vsize == 0) {
rsize = 0;
uexp = 0;
goto done;
}
if ( vp[vsize - 1] != 0)
break;
vsize--, uexp--;
}
}
else
{
usize = 1;
uexp = 1;
up = &ulimb;
}
ASSERT (usize <= prec);
}
if (ediff >= prec)
{
/* V completely cancelled. */
if (rp != up)
MPN_COPY (rp, up, usize);
rsize = usize;
}
else
{
/* If V extends beyond PREC, ignore the part that does.
Note that this can make vsize neither zero nor negative. */
if (vsize + ediff > prec)
{
vp += vsize + ediff - prec;
vsize = prec - ediff;
}
/* Locate the least significant non-zero limb in (the needed
parts of) U and V, to simplify the code below. */
ASSERT (vsize > 0);
for (;;)
{
if (vp[0] != 0)
break;
vp++, vsize--;
if (vsize == 0)
{
MPN_COPY (rp, up, usize);
rsize = usize;
goto done;
}
}
for (;;)
{
if (usize == 0)
{
MPN_COPY (rp, vp, vsize);
rsize = vsize;
negate ^= 1;
goto done;
}
if (up[0] != 0)
break;
up++, usize--;
}
ASSERT (usize > 0 && vsize > 0);
TMP_MARK;
tp = TMP_ALLOC_LIMBS (prec);
/* uuuu | uuuu | uuuu | uuuu | uuuu */
/* vvvvvvv | vv | vvvvv | v | vv */
if (usize > ediff)
{
/* U and V partially overlaps. */
if (ediff == 0)
{
ASSERT (usize == 1 && vsize >= 1 && ulimb == *up); /* usize is 1>ediff, vsize >= 1 */
if (1 < vsize)
{
/* u */
/* vvvvvvv */
rsize = vsize;
vsize -= 1;
/* mpn_cmp (up, vp + vsize - usize, usize) > 0 */
if (ulimb > vp[vsize])
{
tp[vsize] = ulimb - vp[vsize] - 1;
ASSERT_CARRY (mpn_neg (tp, vp, vsize));
}
else
{
/* vvvvvvv */ /* Swap U and V. */
/* u */
MPN_COPY (tp, vp, vsize);
tp[vsize] = vp[vsize] - ulimb;
negate = 1;
}
}
else /* vsize == usize == 1 */
{
/* u */
/* v */
rsize = 1;
negate = ulimb < vp[0];
tp[0] = negate ? vp[0] - ulimb: ulimb - vp[0];
}
}
else
{
ASSERT (vsize + ediff <= usize);
ASSERT (vsize == 1 && usize >= 2 && ulimb == *vp);
{
/* uuuu */
/* v */
mp_size_t size;
size = usize - ediff - 1;
MPN_COPY (tp, up, size);
ASSERT_NOCARRY (mpn_sub_1 (tp + size, up + size, usize - size, ulimb));
rsize = usize;
}
/* Other cases are not possible */
/* uuuu */
/* vvvvv */
}
}
else
{
/* uuuu */
/* vv */
mp_size_t size, i;
ASSERT_CARRY (mpn_neg (tp, vp, vsize));
rsize = vsize + ediff;
size = rsize - usize;
for (i = vsize; i < size; i++)
tp[i] = GMP_NUMB_MAX;
ASSERT_NOCARRY (mpn_sub_1 (tp + size, up, usize, CNST_LIMB (1)));
}
/* Full normalize. Optimize later. */
while (rsize != 0 && tp[rsize - 1] == 0)
{
rsize--;
uexp--;
}
MPN_COPY (rp, tp, rsize);
TMP_FREE;
}
done:
r->_mp_size = negate ? -rsize : rsize;
r->_mp_exp = uexp;
#endif
}
mp_limb_t mpn_divrem_euclidean_qr_2(mp_ptr qp, mp_ptr xp, mp_size_t xn, mp_srcptr dp)
{
mp_size_t qn;
mp_limb_t qf, t[2], t1[2], q, h, l, d1, d2, i;
int c1, c3, c4;
ASSERT(xn >= 2);
ASSERT_MPN(dp, 2);
ASSERT_MPN(xp, xn);
ASSERT(dp[1] != 0);
qn = xn - 1;
/* ASSERT(!MPN_OVERLAP_P(qp, qn, xp, xn)); */ /* FIXME: correct this overlap requirement */
ASSERT((dp[1]>>(GMP_NUMB_BITS - 1)) != 0);
h = 0;
d1 = dp[1];
d2 = dp[0];
invert_limb(i, d1);
l = xp[xn - 1];
qn = xn - 2;
t[0] = xp[qn];
if (l < d1)
{
h = t[1] = l;
l = t[0] = xp[qn];
qf = 0;
}
else
{
qf = 1;
t[1] = l - d1;
t1[1] = 0;
t1[0] = d2;
if (mpn_sub_n(t, t, t1, 2))
{
qf--;
mpn_add_n(t, t, dp, 2);
}
h = t[1];
l = t[0];
}
for (qn = xn - 3; qn >= 0; qn--)
{
t[0] = xp[qn];
if (h < d1)
{
udiv_qrnnd_preinv(q, t[1], h, l, d1, i);
umul_ppmm(t1[1], t1[0], q, d2);
if (mpn_sub_n(t, t, t1, 2))
{
q--;
if (mpn_add_n(t, t, dp, 2) == 0)
{
q--;
ASSERT_CARRY(mpn_add_n(t, t, dp, 2));
}
}
}
else
{
ASSERT(h == d1);
q = -1;
t[1] = l;
c3 = mpn_add_n(t, t, dp, 2);
c1 = mpn_sub_1(t + 1, t + 1, 1, d2);
c4 = c3 - c1;
if (l >= d1)
{
ASSERT(c3 != 0);
ASSERT(c4 == 0);
} /* our guess is B + 1, so q = B - 1 is correct */
else
{
ASSERT(c4 <= 0); /* our guess is B so q = B - 1 or B - 2 */
if (c4 != 0)
{
q--;
mpn_add_n(t, t, dp, 2);
}
}
}
h = t[1];
l = t[0];
qp[qn] = q;
}
xp[1] = t[1];
xp[0] = t[0];
return qf;
}
