private static void SMix(uint[] B, int BOff, int N, int d, int r)
{
int powN = Integers.NumberOfTrailingZeros(N);
int blocksPerChunk = N >> d;
int chunkCount = 1 << d, chunkMask = blocksPerChunk - 1, chunkPow = powN - d;
int BCount = r * 32;
uint[] blockX1 = new uint[16];
uint[] blockX2 = new uint[16];
uint[] blockY = new uint[BCount];
uint[] X = new uint[BCount];
uint[][] VV = new uint[chunkCount][];
try
{
Array.Copy(B, BOff, X, 0, BCount);
for (int c = 0; c < chunkCount; ++c)
{
uint[] V = new uint[blocksPerChunk * BCount];
VV[c] = V;
int off = 0;
for (int i = 0; i < blocksPerChunk; i += 2)
{
Array.Copy(X, 0, V, off, BCount);
off += BCount;
BlockMix(X, blockX1, blockX2, blockY, r);
Array.Copy(blockY, 0, V, off, BCount);
off += BCount;
BlockMix(blockY, blockX1, blockX2, X, r);
}
}
uint mask = (uint)N - 1;
for (int i = 0; i < N; ++i)
{
int j = (int)(X[BCount - 16] & mask);
uint[] V = VV[j >> chunkPow];
int VOff = (j & chunkMask) * BCount;
Array.Copy(V, VOff, blockY, 0, BCount);
Xor(blockY, X, 0, blockY);
BlockMix(blockY, blockX1, blockX2, X, r);
}
Array.Copy(X, 0, B, BOff, BCount);
}
finally
{
ClearAll(VV);
ClearAll(X, blockX1, blockX2, blockY);
}
}
public void TestNumberOfTrailingZeros()
{
for (int i = 0; i < 31; ++i)
{
Assert.AreEqual(i, Integers.NumberOfTrailingZeros(1 << i));
Assert.AreEqual(i, Integers.NumberOfTrailingZeros(-1 << i));
}
Assert.AreEqual(31, Integers.NumberOfTrailingZeros(int.MinValue));
Assert.AreEqual(32, Integers.NumberOfTrailingZeros(0));
}
private static void InversionStep(uint[] p, uint[] u, int uLen, uint[] x, ref int xc)
{
int len = p.Length;
int count = 0;
while (u[0] == 0)
{
Nat.ShiftDownWord(uLen, u, 0);
count += 32;
}
{
int zeroes = Integers.NumberOfTrailingZeros((int)u[0]);
if (zeroes > 0)
{
Nat.ShiftDownBits(uLen, u, zeroes, 0);
count += zeroes;
}
}
for (int i = 0; i < count; ++i)
{
if ((x[0] & 1) != 0)
{
if (xc < 0)
{
xc += (int)Nat.AddTo(len, p, x);
}
else
{
xc += Nat.SubFrom(len, p, x);
}
}
Debug.Assert(xc == 0 || xc == -1);
Nat.ShiftDownBit(len, x, (uint)xc);
}
}
private static int Legendre(BigInteger a, BigInteger b)
{
//int r = 0, bits = b.IntValue;
//for (;;)
//{
// int lowestSetBit = a.GetLowestSetBit();
// a = a.ShiftRight(lowestSetBit);
// r ^= (bits ^ (bits >> 1)) & (lowestSetBit << 1);
// int cmp = a.CompareTo(b);
// if (cmp == 0)
// break;
// if (cmp < 0)
// {
// BigInteger t = a; a = b; b = t;
// int oldBits = bits;
// bits = b.IntValue;
// r ^= oldBits & bits;
// }
// a = a.Subtract(b);
//}
//return BigInteger.One.Equals(b) ? (1 - (r & 2)) : 0;
int bitLength = b.BitLength;
uint[] A = Nat.FromBigInteger(bitLength, a);
uint[] B = Nat.FromBigInteger(bitLength, b);
int r = 0;
int len = B.Length;
for (;;)
{
while (A[0] == 0)
{
Nat.ShiftDownWord(len, A, 0);
}
int shift = Integers.NumberOfTrailingZeros((int)A[0]);
if (shift > 0)
{
Nat.ShiftDownBits(len, A, shift, 0);
int bits = (int)B[0];
r ^= (bits ^ (bits >> 1)) & (shift << 1);
}
int cmp = Nat.Compare(len, A, B);
if (cmp == 0)
{
break;
}
if (cmp < 0)
{
r ^= (int)(A[0] & B[0]);
uint[] t = A; A = B; B = t;
}
while (A[len - 1] == 0)
{
len = len - 1;
}
Nat.Sub(len, A, B, A);
}
return(Nat.IsOne(len, B) ? (1 - (r & 2)) : 0);
}
private static int Divsteps30Var(int eta, int f0, int g0, int[] t)
{
int u = 1, v = 0, q = 0, r = 1;
int f = f0, g = g0, m, w, x, y, z;
int i = 30, limit, zeros;
for (;;)
{
// Use a sentinel bit to count zeros only up to i.
zeros = Integers.NumberOfTrailingZeros(g | (-1 << i));
g >>= zeros;
u <<= zeros;
v <<= zeros;
eta -= zeros;
i -= zeros;
if (i <= 0)
{
break;
}
Debug.Assert((f & 1) == 1);
Debug.Assert((g & 1) == 1);
Debug.Assert((u * f0 + v * g0) == f << (30 - i));
Debug.Assert((q * f0 + r * g0) == g << (30 - i));
if (eta < 0)
{
eta = -eta;
x = f; f = g; g = -x;
y = u; u = q; q = -y;
z = v; v = r; r = -z;
// Handle up to 6 divsteps at once, subject to eta and i.
limit = (eta + 1) > i ? i : (eta + 1);
m = (int)((uint.MaxValue >> (32 - limit)) & 63U);
w = (f * g * (f * f - 2)) & m;
}
else
{
// Handle up to 4 divsteps at once, subject to eta and i.
limit = (eta + 1) > i ? i : (eta + 1);
m = (int)((uint.MaxValue >> (32 - limit)) & 15U);
w = f + (((f + 1) & 4) << 1);
w = (-w * g) & m;
}
g += f * w;
q += u * w;
r += v * w;
Debug.Assert((g & m) == 0);
}
t[0] = u;
t[1] = v;
t[2] = q;
t[3] = r;
return(eta);
}