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package org.spongycastle.math.ec.custom.sec;
import java.math.BigInteger;
import org.spongycastle.math.raw.Nat;
import org.spongycastle.math.raw.Nat192;
public class SecP192K1Field
{
// 2^192 - 2^32 - 2^12 - 2^8 - 2^7 - 2^6 - 2^3 - 1
static final int[] P = new int[]{ 0xFFFFEE37, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
static final int[] PExt = new int[]{ 0x013C4FD1, 0x00002392, 0x00000001, 0x00000000, 0x00000000,
0x00000000, 0xFFFFDC6E, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
private static final int[] PExtInv = new int[]{ 0xFEC3B02F, 0xFFFFDC6D, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF,
0xFFFFFFFF, 0x00002391, 0x00000002 };
private static final int P5 = 0xFFFFFFFF;
private static final int PExt11 = 0xFFFFFFFF;
private static final int PInv33 = 0x11C9;
public static void add(int[] x, int[] y, int[] z)
{
int c = Nat192.add(x, y, z);
if (c != 0 || (z[5] == P5 && Nat192.gte(z, P)))
{
Nat.add33To(6, PInv33, z);
}
}
public static void addExt(int[] xx, int[] yy, int[] zz)
{
int c = Nat.add(12, xx, yy, zz);
if (c != 0 || (zz[11] == PExt11 && Nat.gte(12, zz, PExt)))
{
if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0)
{
Nat.incAt(12, zz, PExtInv.length);
}
}
}
public static void addOne(int[] x, int[] z)
{
int c = Nat.inc(6, x, z);
if (c != 0 || (z[5] == P5 && Nat192.gte(z, P)))
{
Nat.add33To(6, PInv33, z);
}
}
public static int[] fromBigInteger(BigInteger x)
{
int[] z = Nat192.fromBigInteger(x);
if (z[5] == P5 && Nat192.gte(z, P))
{
Nat192.subFrom(P, z);
}
return z;
}
public static void half(int[] x, int[] z)
{
if ((x[0] & 1) == 0)
{
Nat.shiftDownBit(6, x, 0, z);
}
else
{
int c = Nat192.add(x, P, z);
Nat.shiftDownBit(6, z, c);
}
}
public static void multiply(int[] x, int[] y, int[] z)
{
int[] tt = Nat192.createExt();
Nat192.mul(x, y, tt);
reduce(tt, z);
}
public static void multiplyAddToExt(int[] x, int[] y, int[] zz)
{
int c = Nat192.mulAddTo(x, y, zz);
if (c != 0 || (zz[11] == PExt11 && Nat.gte(12, zz, PExt)))
{
if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0)
{
Nat.incAt(12, zz, PExtInv.length);
}
}
}
public static void negate(int[] x, int[] z)
{
if (Nat192.isZero(x))
{
Nat192.zero(z);
}
else
{
Nat192.sub(P, x, z);
}
}
public static void reduce(int[] xx, int[] z)
{
long cc = Nat192.mul33Add(PInv33, xx, 6, xx, 0, z, 0);
int c = Nat192.mul33DWordAdd(PInv33, cc, z, 0);
// assert c == 0L || c == 1L;
if (c != 0 || (z[5] == P5 && Nat192.gte(z, P)))
{
Nat.add33To(6, PInv33, z);
}
}
public static void reduce32(int x, int[] z)
{
if ((x != 0 && Nat192.mul33WordAdd(PInv33, x, z, 0) != 0)
|| (z[5] == P5 && Nat192.gte(z, P)))
{
Nat.add33To(6, PInv33, z);
}
}
public static void square(int[] x, int[] z)
{
int[] tt = Nat192.createExt();
Nat192.square(x, tt);
reduce(tt, z);
}
public static void squareN(int[] x, int n, int[] z)
{
// assert n > 0;
int[] tt = Nat192.createExt();
Nat192.square(x, tt);
reduce(tt, z);
while (--n > 0)
{
Nat192.square(z, tt);
reduce(tt, z);
}
}
public static void subtract(int[] x, int[] y, int[] z)
{
int c = Nat192.sub(x, y, z);
if (c != 0)
{
Nat.sub33From(6, PInv33, z);
}
}
public static void subtractExt(int[] xx, int[] yy, int[] zz)
{
int c = Nat.sub(12, xx, yy, zz);
if (c != 0)
{
if (Nat.subFrom(PExtInv.length, PExtInv, zz) != 0)
{
Nat.decAt(12, zz, PExtInv.length);
}
}
}
public static void twice(int[] x, int[] z)
{
int c = Nat.shiftUpBit(6, x, 0, z);
if (c != 0 || (z[5] == P5 && Nat192.gte(z, P)))
{
Nat.add33To(6, PInv33, z);
}
}
}
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