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using System;
using System.Diagnostics;
namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
internal class SecP224R1Field
{
// 2^224 - 2^96 + 1
internal static readonly uint[] P = new uint[] { 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
private const uint P6 = 0xFFFFFFFF;
private static readonly uint[] PExt = new uint[]{ 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF,
0xFFFFFFFF, 0x00000000, 0x00000002, 0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
private const uint PExt13 = 0xFFFFFFFF;
public static void Add(uint[] x, uint[] y, uint[] z)
{
uint c = Nat224.Add(x, y, z);
if (c != 0 || (z[6] == P6 && Nat224.Gte(z, P)))
{
Nat224.Sub(z, P, z);
}
}
public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
{
uint c = Nat224.AddExt(xx, yy, zz);
if (c != 0 || (zz[13] == PExt13 && Nat224.GteExt(zz, PExt)))
{
Nat224.SubExt(zz, PExt, zz);
}
}
public static void AddOne(uint[] x, uint[] z)
{
Array.Copy(x, 0, z, 0, 6);
uint c = Nat224.Inc(z, 0);
if (c != 0 || (z[6] == P6 && Nat224.Gte(z, P)))
{
Nat224.Sub(z, P, z);
}
}
public static uint[] FromBigInteger(BigInteger x)
{
uint[] z = Nat224.FromBigInteger(x);
if (z[6] == P6 && Nat224.Gte(z, P))
{
Nat224.Sub(z, P, z);
}
return z;
}
public static void Half(uint[] x, uint[] z)
{
if ((x[0] & 1) == 0)
{
Nat224.ShiftDownBit(x, 0, z);
}
else
{
uint c = Nat224.Add(x, P, z);
Nat224.ShiftDownBit(z, c, z);
}
}
public static void Multiply(uint[] x, uint[] y, uint[] z)
{
uint[] tt = Nat224.CreateExt();
Nat224.Mul(x, y, tt);
Reduce(tt, z);
}
public static void Negate(uint[] x, uint[] z)
{
if (Nat224.IsZero(x))
{
Nat224.Zero(z);
}
else
{
Nat224.Sub(P, x, z);
}
}
public static void Reduce(uint[] xx, uint[] z)
{
long xx07 = xx[7], xx08 = xx[8], xx09 = xx[9], xx10 = xx[10];
long xx11 = xx[11], xx12 = xx[12], xx13 = xx[13];
long t0 = xx07 + xx11;
long t1 = xx08 + xx12;
long t2 = xx09 + xx13;
long cc = 0;
cc += (long)xx[0] - t0;
z[0] = (uint)cc;
cc >>= 32;
cc += (long)xx[1] - t1;
z[1] = (uint)cc;
cc >>= 32;
cc += (long)xx[2] - t2;
z[2] = (uint)cc;
cc >>= 32;
cc += (long)xx[3] + t0 - xx10;
z[3] = (uint)cc;
cc >>= 32;
cc += (long)xx[4] + t1 - xx11;
z[4] = (uint)cc;
cc >>= 32;
cc += (long)xx[5] + t2 - xx12;
z[5] = (uint)cc;
cc >>= 32;
cc += (long)xx[6] + xx10 - xx13;
z[6] = (uint)cc;
cc >>= 32;
int c = (int)cc;
if (c < 0)
{
do
{
c += (int)Nat224.Add(z, P, z);
}
while (c < 0);
}
else
{
while (c > 0)
{
c += Nat224.Sub(z, P, z);
}
if (z[6] == P6 && Nat224.Gte(z, P))
{
Nat224.Sub(z, P, z);
}
}
}
public static void Square(uint[] x, uint[] z)
{
uint[] tt = Nat224.CreateExt();
Nat224.Square(x, tt);
Reduce(tt, z);
}
public static void SquareN(uint[] x, int n, uint[] z)
{
Debug.Assert(n > 0);
uint[] tt = Nat224.CreateExt();
Nat224.Square(x, tt);
Reduce(tt, z);
while (--n > 0)
{
Nat224.Square(z, tt);
Reduce(tt, z);
}
}
public static void Subtract(uint[] x, uint[] y, uint[] z)
{
int c = Nat224.Sub(x, y, z);
if (c != 0)
{
Nat224.Add(z, P, z);
}
}
public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
{
int c = Nat224.SubExt(xx, yy, zz);
if (c != 0)
{
Nat224.AddExt(zz, PExt, zz);
}
}
public static void Twice(uint[] x, uint[] z)
{
uint c = Nat224.ShiftUpBit(x, 0, z);
if (c != 0 || (z[6] == P6 && Nat224.Gte(z, P)))
{
Nat224.Sub(z, P, z);
}
}
}
}
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