Mul22S(Digit[] mat, Digits vec1, Digits vec2, int lvec, int[] carrys)
{
int carry1 = 0, carry2 = 0;
Digit m11 = mat[0], m12 = mat[1], m21 = mat[2], m22 = mat[3];
if (((m11 | m12 | m21 | m22) & 1U << Digit.BitN - 1) != 0)
{
throw new ArgumentException();
}
for (int i = 0; i != lvec; i++)
{
UInt64 prod11 = (UInt64)m11 * vec1[i]
, prod12 = (UInt64)m12 * vec2[i]
, prod21 = (UInt64)m21 * vec1[i]
, prod22 = (UInt64)m22 * vec2[i]
, prod1 = unchecked (prod11 + (UInt64)carry1)
, prod2 = unchecked (prod22 + (UInt64)carry2);
prod1 = unchecked (prod1 - prod12);
prod2 = unchecked (prod2 - prod21);
vec1[i] = Digit2.Lo(prod1);
vec2[i] = Digit2.Lo(prod2);
carry1 = unchecked ((int)Digit2.Hi(prod1));
carry2 = unchecked ((int)Digit2.Hi(prod2));
}
carrys[0] = carry1;
carrys[1] = carry2;
}
internal static bool DivisibleBySomeLowPrime(Digits digits, int n)
{
if (n == 0 || (digits[0] & 1) == 0)
{
Debug.Assert(false, "untested code");
return(true);
}
for (int l = 0; l != LowPrimesProduct.Length; l++)
{
Digit product = LowPrimesProduct[l]
, productInverse = Digit.TwoAdicInverse(product)
, r = 0;
for (int i = 0; i != n; i++)
{
Digit mulby;
unchecked {
r += digits[i];
if (r < digits[i])
{
r -= product;
}
mulby = productInverse * r;
Debug.Assert(mulby * product == r, "internal error");
}
r = product - Digit2.Hi((UInt64)mulby * product);
}
if (Digit.OddGcd(r, product) != 1)
{
return(true);
}
}
return(false);
}
static void Mul22U(
Digit[] mat
, Digits vec1
, Digits vec2
, int lvec
, Digits carrys
)
{
Digit carry1 = 0, carry2 = 0;
Digit m11 = mat[0], m12 = mat[1], m21 = mat[2], m22 = mat[3];
if (m12 > Digit.MaxValue - m11 || m21 > Digit.MaxValue - m22)
{
throw new ArgumentException();
}
for (int i = 0; i != lvec; i++)
{
UInt64 prod11 = (UInt64)m11 * vec1[i] + carry1
, prod21 = (UInt64)m21 * vec1[i] + carry2
, prod12 = (UInt64)m12 * vec2[i] + Digit2.Lo(prod11)
, prod22 = (UInt64)m22 * vec2[i] + Digit2.Lo(prod21);
vec1[i] = Digit2.Lo(prod12);
vec2[i] = Digit2.Lo(prod22);
carry1 = Digit2.Hi(prod11) + Digit2.Hi(prod12);
carry2 = Digit2.Hi(prod21) + Digit2.Hi(prod22);
}
carrys[0] = carry1;
carrys[1] = carry2;
}
internal static Digit Mul(Digits a, Digit mult, Digits b, int n)
{
Digit carry = 0;
for (int i = 0; i != n; i++)
{
UInt64 dtemp = (UInt64)mult * a[i] + carry;
b[i] = Digit2.Lo(dtemp);
carry = Digit2.Hi(dtemp);
}
return(carry);
}
Accumulate(Digits a, Digit mult, Digits b, int n)
{
Digit carry = 0;
for (int i = 0; i != n; i++)
{
UInt64 dtemp = (UInt64)mult * a[i] + b[i] + carry;
b[i] = Digit2.Lo(dtemp);
carry = Digit2.Hi(dtemp);
}
return(carry);
}
void _MulFromRight(Digits a, Digits b, Digits c)
{
Digit minv = _rightRecip
, minva0 = unchecked (minv * a[0])
, mul1 = b[0]
, mul2 = unchecked (minva0 * mul1)
, carry1 = Digit2.Hi((UInt64)mul1 * a[0])
, carry2 = Digit2.Hi((UInt64)mul2 * _mod[0]);
UInt64 prod1, prod2;
Debug.Assert(unchecked (mul1 * a[0]) == unchecked (mul2 * _mod[0])
, "internal error");
Digits temp1 = new Digits(_digitN), temp2 = new Digits(_digitN);
for (int i = 1; i != _digitN; i++)
{
prod1 = (UInt64)mul1 * a[i] + carry1;
prod2 = (UInt64)mul2 * _mod[i] + carry2;
temp1[i - 1] = Digit2.Lo(prod1);
temp2[i - 1] = Digit2.Lo(prod2);
carry1 = Digit2.Hi(prod1);
carry2 = Digit2.Hi(prod2);
}
temp1[_digitN - 1] = carry1;
temp2[_digitN - 1] = carry2;
for (int j = 1; j != _digitN; j++)
{
mul1 = b[j];
mul2 = unchecked (minva0 * mul1 + minv * (temp1[0] - temp2[0]));
prod1 = (UInt64)mul1 * a[0] + temp1[0];
prod2 = (UInt64)mul2 * _mod[0] + temp2[0];
Debug.Assert(Digit2.Lo(prod1) == Digit2.Lo(prod2)
, "internal error");
carry1 = Digit2.Hi(prod1);
carry2 = Digit2.Hi(prod2);
for (int i = 1; i != _digitN; i++)
{
prod1 = (UInt64)mul1 * a[i] + temp1[i] + carry1;
prod2 = (UInt64)mul2 * _mod[i] + temp2[i] + carry2;
temp1[i - 1] = Digit2.Lo(prod1);
temp2[i - 1] = Digit2.Lo(prod2);
carry1 = Digit2.Hi(prod1);
carry2 = Digit2.Hi(prod2);
}
temp1[_digitN - 1] = carry1;
temp2[_digitN - 1] = carry2;
}
Modular.Sub(temp1, temp2, c, _mod, _digitN);
}
DivPrecondition(Digits denom, int denomN, Reciprocal recip)
{
if (denom == null)
{
throw new ArgumentNullException();
}
if (denomN == 0 || denom[denomN - 1] == 0)
{
throw new ArgumentException();
}
int recipBitShift = Digit.BitN - Digit.SigBitN(denom[denomN - 1]);
Digit dlead2 = denom[denomN - 1]
, dlead1 = denomN >= 2 ? denom[denomN - 2] : 0
, dlead0 = denomN >= 3 ? denom[denomN - 3] : 0
, dShiftHi = dlead2 << recipBitShift
| dlead1 >> 1 >> Digit.BitN - 1 - recipBitShift
, dShiftLo = dlead1 << recipBitShift
| dlead0 >> 1 >> Digit.BitN - 1 - recipBitShift;
Digit recipMpy, r;
Digit2.Div((UInt64)(Digit.MaxValue - dShiftHi) << Digit.BitN
| Digit.MaxValue - dShiftLo
, dShiftHi
, out recipMpy
, out r);
if (Digit2.Hi((UInt64)recipMpy * dShiftLo) > r)
{
recipMpy -= 1;
}
r = (Digit.MaxValue >> recipBitShift) - denom[denomN - 1];
for (int id = denomN; id-- != 0 && r < recipMpy;)
{
UInt64 test1 = (UInt64)r << Digit.BitN
| Digit.MaxValue - (id > 0 ? denom[id - 1] : 0)
, test2 = (UInt64)recipMpy * denom[id];
if (test2 > test1)
{
recipMpy -= 1; break;
}
test1 = test1 - test2;
r = Digit2.Lo(test1);
if (Digit2.Hi(test1) != 0)
{
break;
}
}
recip._shiftBitN = recipBitShift;
recip._multiplier = recipMpy;
}
Decumulate(Digits a, Digit mult, Digits b, int n)
{
Digit borrow = 0;
for (int i = 0; i != n; i++)
{
UInt64 dtemp;
unchecked {
dtemp = (UInt64)b[i] - borrow - (UInt64)mult * a[i];
}
b[i] = Digit2.Lo(dtemp);
unchecked { borrow = 0 - Digit2.Hi(dtemp); }
}
return(borrow);
}
internal Digit EstQuotient(Digit n2, Digit n1, Digit n0)
{
Digit nShiftHi
= n2 << _shiftBitN | n1 >> 1 >> Digit.BitN - 1 - _shiftBitN
, nShiftLo
= n1 << _shiftBitN | n0 >> 1 >> Digit.BitN - 1 - _shiftBitN;
UInt64 qprod = ((UInt64)nShiftHi << Digit.BitN | nShiftLo)
+ (UInt64)nShiftHi * _multiplier;
if ((nShiftLo & 1U << Digit.BitN - 1) != 0)
{
qprod += _multiplier >> 1;
}
return(Digit2.Hi(qprod));
}
LehmerMat22(UInt64 lead0orig, UInt64 lead1orig, Digit[] mat22)
{
Digit lead0h = Digit2.Hi(lead0orig)
, lead0l = Digit2.Lo(lead0orig)
, lead1h = Digit2.Hi(lead1orig)
, lead1l = Digit2.Lo(lead1orig);
bool progress = true;
Digit m00 = 1, m01 = 0, m10 = 0, m11 = 1;
Debug.Assert(lead0h != 0 &&
lead1h != 0 &&
((lead0h | lead1h) & 1U << Digit.BitN - 1) != 0
, "internal error");
while (progress)
{
progress = false;
if (lead0h - 1 > lead1h && lead0h != 0)
{
if (lead0h >> 2 >= lead1h + 2)
{
Digit q = lead0h / (lead1h + 2);
UInt64 prod10By11 = (UInt64)q * (m10 + m11)
, prod1l = (UInt64)q * lead1l;
Debug.Assert(q > 3, "internal error");
if (
Digit2.Hi(prod10By11) == 0 &&
Digit2.Lo(prod10By11)
<= Digit.MaxValue / 2 - m00 - m01
)
{
Digit prod10 = q * m10;
progress = true;
lead0h
-= (Digit)((long)(UInt32)q * lead1h
+ Digit2.Hi(prod1l)
+ (Digit2.Lo(prod1l) > lead0l ? 1L : 0L));
unchecked { lead0l -= Digit2.Lo(prod1l); }
m00 += prod10;
m01 += Digit2.Lo(prod10By11) - prod10;
Debug.Assert((m00 | m01) < 1U << Digit.BitN - 1
, "internal error");
}
}
else
{
Digit overflowTest;
do
{
m00 += m10;
m01 += m11;
overflowTest = (m00 | m01) & 1U << Digit.BitN - 1;
lead0h -= lead1h + (lead1l > lead0l ? 1U : 0U);
unchecked { lead0l -= lead1l; }
} while (overflowTest == 0 && lead0h >= lead1h + 2);
progress = true;
if (overflowTest != 0)
{
progress = false;
m00 -= m10;
m01 -= m11;
}
}
}
if (lead1h - 1 > lead0h && lead1h != 0)
{
if (lead1h >> 2 >= lead0h + 2)
{
Digit q = lead1h / (lead0h + 2);
UInt64 prod00And01 = (UInt64)q * (m00 + m01)
, prod0l = (UInt64)q * lead0l;
Debug.Assert(q > 3, "internal error");
if (
Digit2.Hi(prod00And01) == 0 &&
Digit2.Lo(prod00And01)
<= Digit.MaxValue / 2 - m10 - m11
)
{
Digit prod00 = q * m00;
progress = true;
lead1h -= q * lead0h
+ Digit2.Hi(prod0l)
+ (Digit2.Lo(prod0l) > lead1l ? 1U : 0U);
unchecked { lead1l -= Digit2.Lo(prod0l); }
m10 += prod00;
m11 += Digit2.Lo(prod00And01) - prod00;
Debug.Assert((m10 | m11) < 1U << Digit.BitN - 1
, "internal error");
}
}
else
{
Digit overflowTest;
do
{
m10 += m00;
m11 += m01;
overflowTest = (m10 | m11) & 1U << Digit.BitN - 1;
lead1h -= lead0h + (lead0l > lead1l ? 1U : 0U);
unchecked { lead1l -= lead0l; }
} while (overflowTest == 0 && lead1h >= lead0h + 2);
progress = true;
if (overflowTest != 0)
{
progress = false;
m10 -= m00;
m11 -= m01;
}
}
}
}
Debug.Assert(((m00 | m01 | m10 | m11) & 1U << Digit.BitN - 1) == 0
, "internal error");
mat22[0] = m00;
mat22[1] = m01;
mat22[2] = m10;
mat22[3] = m11;
}