private static void ge_p2_dbl(ref ge_p1p1 r, ge_p2 p)
{
Span <int> t0 = stackalloc int[10];
ge_p1p1 result = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
T = stackalloc int[10],
};
r.X.CopyTo(result.X);
r.Y.CopyTo(result.Y);
r.Z.CopyTo(result.Z);
r.T.CopyTo(result.T);
fe_sq(ref result.X, p.X);
fe_sq(ref result.Z, p.Y);
fe_sq2(ref result.T, p.Z);
fe_add(ref result.Y, p.X, p.Y);
fe_sq(ref t0, result.Y);
fe_add(ref result.Y, result.Z, result.X);
fe_sub(ref result.Z, result.Z, result.X);
fe_sub(ref result.X, t0, result.Y);
fe_sub(ref result.T, result.T, result.Z);
result.X.CopyTo(r.X);
result.Y.CopyTo(r.Y);
result.Z.CopyTo(r.Z);
result.T.CopyTo(r.T);
}
private static void ge_p3_to_p2(ref ge_p2 r, ge_p3 p)
{
ge_p2 result = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
};
fe_copy(ref result.X, p.X);
fe_copy(ref result.Y, p.Y);
fe_copy(ref result.Z, p.Z);
result.X.CopyTo(r.X);
result.Y.CopyTo(r.Y);
result.Z.CopyTo(r.Z);
}
private static void ge_p2_0(ref ge_p2 h)
{
ge_p2 result = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
};
fe_0(ref result.X);
fe_1(ref result.Y);
fe_1(ref result.Z);
result.X.CopyTo(h.X);
result.Y.CopyTo(h.Y);
result.Z.CopyTo(h.Z);
}
private static void ge_tobytes(ref Span <byte> s, ge_p2 h)
{
Span <int> x = stackalloc int[10];
Span <int> y = stackalloc int[10];
Span <int> recip = stackalloc int[10];
Span <byte> result = stackalloc byte[32];
s.CopyTo(result);
fe_invert(ref recip, h.Z);
fe_mul(ref x, h.X, recip);
fe_mul(ref y, h.Y, recip);
fe_tobytes(ref result, y);
result[31] ^= (byte)(fe_isnegative(x) << 7);
result.CopyTo(s);
}
private static void ge_double_scalarmult_vartime(ref ge_p2 r, ReadOnlySpan <byte> a, ge_p3 A, ReadOnlySpan <byte> b)
{
Span <sbyte> aslide = stackalloc sbyte[256];
Span <sbyte> bslide = stackalloc sbyte[256];
ge_p2 result = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
};
r.X.CopyTo(result.X);
r.Y.CopyTo(result.Y);
r.Z.CopyTo(result.Z);
/* A,3A,5A,7A,9A,11A,13A,15A */
ge_cached Ai0 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai1 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai2 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai3 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai4 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai5 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai6 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_cached Ai7 = new()
{
YplusX = stackalloc int[10],
T2d = stackalloc int[10],
YminusX = stackalloc int[10],
Z = stackalloc int[10],
};
ge_p1p1 t = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
T = stackalloc int[10],
};
ge_p3 u = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
T = stackalloc int[10],
};
ge_p3 A2 = new()
{
X = stackalloc int[10],
Y = stackalloc int[10],
Z = stackalloc int[10],
T = stackalloc int[10],
};
int i;
slide(ref aslide, a);
slide(ref bslide, b);
ge_p3_to_cached(ref Ai0, A);
ge_p3_dbl(ref t, A);
ge_p1p1_to_p3(ref A2, t);
ge_add(ref t, A2, Ai0);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai1, u);
ge_add(ref t, A2, Ai1);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai2, u);
ge_add(ref t, A2, Ai2);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai3, u);
ge_add(ref t, A2, Ai3);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai4, u);
ge_add(ref t, A2, Ai4);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai5, u);
ge_add(ref t, A2, Ai5);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai6, u);
ge_add(ref t, A2, Ai6);
ge_p1p1_to_p3(ref u, t);
ge_p3_to_cached(ref Ai7, u);
ge_p2_0(ref result);
ge_precomp bi = new()
{
yminusx = stackalloc int[10],
yplusx = stackalloc int[10],
xy2d = stackalloc int[10],
};
for (i = 255; i >= 0; --i)
{
if (aslide[i] != 0 || bslide[i] != 0)
{
break;
}
}
for (; i >= 0; --i)
{
ge_p2_dbl(ref t, result);
switch (aslide[i])
{
case > 0:
{
ge_p1p1_to_p3(ref u, t);
switch (aslide[i] / 2)
{
case 0:
ge_add(ref t, u, Ai0);
break;
case 1:
ge_add(ref t, u, Ai1);
break;
case 2:
ge_add(ref t, u, Ai2);
break;
case 3:
ge_add(ref t, u, Ai3);
break;
case 4:
ge_add(ref t, u, Ai4);
break;
case 5:
ge_add(ref t, u, Ai5);
break;
case 6:
ge_add(ref t, u, Ai6);
break;
case 7:
ge_add(ref t, u, Ai7);
break;
}
break;
}
case < 0:
{
ge_p1p1_to_p3(ref u, t);
switch (-aslide[i] / 2)
{
case 0:
ge_sub(ref t, u, Ai0);
break;
case 1:
ge_sub(ref t, u, Ai1);
break;
case 2:
ge_sub(ref t, u, Ai2);
break;
case 3:
ge_sub(ref t, u, Ai3);
break;
case 4:
ge_sub(ref t, u, Ai4);
break;
case 5:
ge_sub(ref t, u, Ai5);
break;
case 6:
ge_sub(ref t, u, Ai6);
break;
case 7:
ge_sub(ref t, u, Ai7);
break;
}
break;
}
}
switch (bslide[i])
{
case > 0:
{
GetPrecompBi(bslide[i] / 2, ref bi);
ge_p1p1_to_p3(ref u, t);
ge_madd(ref t, u, bi);
break;
}
case < 0:
{
GetPrecompBi(-bslide[i] / 2, ref bi);
ge_p1p1_to_p3(ref u, t);
ge_msub(ref t, u, bi);
break;
}
}
ge_p1p1_to_p2(ref result, t);
}
result.X.CopyTo(r.X);
result.Y.CopyTo(r.Y);
result.Z.CopyTo(r.Z);
}