diff options
Diffstat (limited to 'crypto/src/math/ec/rfc8032/Scalar25519.cs')
| -rw-r--r-- | crypto/src/math/ec/rfc8032/Scalar25519.cs | 782 |
1 files changed, 782 insertions, 0 deletions
diff --git a/crypto/src/math/ec/rfc8032/Scalar25519.cs b/crypto/src/math/ec/rfc8032/Scalar25519.cs new file mode 100644 index 000000000..738ce63cb --- /dev/null +++ b/crypto/src/math/ec/rfc8032/Scalar25519.cs @@ -0,0 +1,782 @@ +using System; +using System.Diagnostics; +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER +using System.Runtime.CompilerServices; +using System.Runtime.InteropServices; +#endif + +using Org.BouncyCastle.Crypto.Utilities; +using Org.BouncyCastle.Math.Raw; +using Org.BouncyCastle.Utilities; + +namespace Org.BouncyCastle.Math.EC.Rfc8032 +{ + internal static class Scalar25519 + { + internal const int Size = 8; + + private const long M08L = 0x000000FFL; + private const long M28L = 0x0FFFFFFFL; + private const long M32L = 0xFFFFFFFFL; + + private const int TargetLength = 254; + + private static readonly uint[] L = { 0x5CF5D3EDU, 0x5812631AU, 0xA2F79CD6U, 0x14DEF9DEU, 0x00000000U, + 0x00000000U, 0x00000000U, 0x10000000U }; + private static readonly uint[] LSq = { 0xAB128969U, 0xE2EDF685U, 0x2298A31DU, 0x68039276U, 0xD217F5BEU, + 0x3DCEEC73U, 0x1B7C309AU, 0xA1B39941U, 0x4B9EBA7DU, 0xCB024C63U, 0xD45EF39AU, 0x029BDF3BU, 0x00000000U, + 0x00000000U, 0x00000000U, 0x01000000U }; + + private const int L0 = -0x030A2C13; // L0:26/-- + private const int L1 = 0x012631A6; // L1:24/22 + private const int L2 = 0x079CD658; // L2:27/-- + private const int L3 = -0x006215D1; // L3:23/-- + private const int L4 = 0x000014DF; // L4:12/11 + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static bool CheckVar(ReadOnlySpan<byte> s, Span<uint> n) + { + Decode(s, n); + return !Nat.Gte(Size, n, L); + } +#else + internal static bool CheckVar(byte[] s, uint[] n) + { + Decode(s, n); + return !Nat256.Gte(n, L); + } +#endif + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void Decode(ReadOnlySpan<byte> k, Span<uint> n) + { + Codec.Decode32(k, n[..Size]); + } +#else + internal static void Decode(byte[] k, uint[] n) + { + Codec.Decode32(k, 0, n, 0, Size); + } +#endif + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void GetOrderWnafVar(int width, Span<sbyte> ws) +#else + internal static void GetOrderWnafVar(int width, sbyte[] ws) +#endif + { + Wnaf.GetSignedVar(L, width, ws); + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void Multiply128Var(ReadOnlySpan<uint> x, ReadOnlySpan<uint> y128, Span<uint> z) + { + Span<uint> tt = stackalloc uint[16]; + Nat.Mul(y128, x, tt); + + if ((y128[3] >> 31) != 0) + { + Nat.AddTo(8, L, tt[4..]); + Nat.SubFrom(8, x, tt[4..]); + } + + Span<byte> r = MemoryMarshal.AsBytes(tt); + Reduce(r, r); + tt[..8].CopyTo(z); + } +#else + internal static void Multiply128Var(uint[] x, uint[] y128, uint[] z) + { + uint[] tt = new uint[12]; + Nat.Mul(y128, 0, 4, x, 0, 8, tt, 0); + + if ((y128[3] >> 31) != 0) + { + Nat256.AddTo(L, 0, tt, 4, 0U); + Nat256.SubFrom(x, 0, tt, 4); + } + + byte[] bytes = new byte[64]; + Codec.Encode32(tt, 0, 12, bytes, 0); + + byte[] r = Reduce(bytes); + Codec.Decode32(r, 0, z, 0, 8); + } +#endif + + internal static byte[] Reduce(byte[] n) + { + byte[] r = new byte[64]; + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + Reduce(n, r); +#else + long x00 = Codec.Decode32(n, 0) & M32L; // x00:32/-- + long x01 = (Codec.Decode24(n, 4) << 4) & M32L; // x01:28/-- + long x02 = Codec.Decode32(n, 7) & M32L; // x02:32/-- + long x03 = (Codec.Decode24(n, 11) << 4) & M32L; // x03:28/-- + long x04 = Codec.Decode32(n, 14) & M32L; // x04:32/-- + long x05 = (Codec.Decode24(n, 18) << 4) & M32L; // x05:28/-- + long x06 = Codec.Decode32(n, 21) & M32L; // x06:32/-- + long x07 = (Codec.Decode24(n, 25) << 4) & M32L; // x07:28/-- + long x08 = Codec.Decode32(n, 28) & M32L; // x08:32/-- + long x09 = (Codec.Decode24(n, 32) << 4) & M32L; // x09:28/-- + long x10 = Codec.Decode32(n, 35) & M32L; // x10:32/-- + long x11 = (Codec.Decode24(n, 39) << 4) & M32L; // x11:28/-- + long x12 = Codec.Decode32(n, 42) & M32L; // x12:32/-- + long x13 = (Codec.Decode24(n, 46) << 4) & M32L; // x13:28/-- + long x14 = Codec.Decode32(n, 49) & M32L; // x14:32/-- + long x15 = (Codec.Decode24(n, 53) << 4) & M32L; // x15:28/-- + long x16 = Codec.Decode32(n, 56) & M32L; // x16:32/-- + long x17 = (Codec.Decode24(n, 60) << 4) & M32L; // x17:28/-- + long x18 = n[63] & M08L; // x18:08/-- + long t; + + //x18 += (x17 >> 28); x17 &= M28L; + x09 -= x18 * L0; // x09:34/28 + x10 -= x18 * L1; // x10:33/30 + x11 -= x18 * L2; // x11:35/28 + x12 -= x18 * L3; // x12:32/31 + x13 -= x18 * L4; // x13:28/21 + + x17 += (x16 >> 28); x16 &= M28L; // x17:28/--, x16:28/-- + x08 -= x17 * L0; // x08:54/32 + x09 -= x17 * L1; // x09:52/51 + x10 -= x17 * L2; // x10:55/34 + x11 -= x17 * L3; // x11:51/36 + x12 -= x17 * L4; // x12:41/-- + + //x16 += (x15 >> 28); x15 &= M28L; + x07 -= x16 * L0; // x07:54/28 + x08 -= x16 * L1; // x08:54/53 + x09 -= x16 * L2; // x09:55/53 + x10 -= x16 * L3; // x10:55/52 + x11 -= x16 * L4; // x11:51/41 + + x15 += (x14 >> 28); x14 &= M28L; // x15:28/--, x14:28/-- + x06 -= x15 * L0; // x06:54/32 + x07 -= x15 * L1; // x07:54/53 + x08 -= x15 * L2; // x08:56/-- + x09 -= x15 * L3; // x09:55/54 + x10 -= x15 * L4; // x10:55/53 + + //x14 += (x13 >> 28); x13 &= M28L; + x05 -= x14 * L0; // x05:54/28 + x06 -= x14 * L1; // x06:54/53 + x07 -= x14 * L2; // x07:56/-- + x08 -= x14 * L3; // x08:56/51 + x09 -= x14 * L4; // x09:56/-- + + x13 += (x12 >> 28); x12 &= M28L; // x13:28/22, x12:28/-- + x04 -= x13 * L0; // x04:54/49 + x05 -= x13 * L1; // x05:54/53 + x06 -= x13 * L2; // x06:56/-- + x07 -= x13 * L3; // x07:56/52 + x08 -= x13 * L4; // x08:56/52 + + x12 += (x11 >> 28); x11 &= M28L; // x12:28/24, x11:28/-- + x03 -= x12 * L0; // x03:54/49 + x04 -= x12 * L1; // x04:54/51 + x05 -= x12 * L2; // x05:56/-- + x06 -= x12 * L3; // x06:56/52 + x07 -= x12 * L4; // x07:56/53 + + x11 += (x10 >> 28); x10 &= M28L; // x11:29/--, x10:28/-- + x02 -= x11 * L0; // x02:55/32 + x03 -= x11 * L1; // x03:55/-- + x04 -= x11 * L2; // x04:56/55 + x05 -= x11 * L3; // x05:56/52 + x06 -= x11 * L4; // x06:56/53 + + x10 += (x09 >> 28); x09 &= M28L; // x10:29/--, x09:28/-- + x01 -= x10 * L0; // x01:55/28 + x02 -= x10 * L1; // x02:55/54 + x03 -= x10 * L2; // x03:56/55 + x04 -= x10 * L3; // x04:57/-- + x05 -= x10 * L4; // x05:56/53 + + x08 += (x07 >> 28); x07 &= M28L; // x08:56/53, x07:28/-- + x09 += (x08 >> 28); x08 &= M28L; // x09:29/25, x08:28/-- + + t = (x08 >> 27) & 1L; + x09 += t; // x09:29/26 + + x00 -= x09 * L0; // x00:55/53 + x01 -= x09 * L1; // x01:55/54 + x02 -= x09 * L2; // x02:57/-- + x03 -= x09 * L3; // x03:57/-- + x04 -= x09 * L4; // x04:57/42 + + x01 += (x00 >> 28); x00 &= M28L; + x02 += (x01 >> 28); x01 &= M28L; + x03 += (x02 >> 28); x02 &= M28L; + x04 += (x03 >> 28); x03 &= M28L; + x05 += (x04 >> 28); x04 &= M28L; + x06 += (x05 >> 28); x05 &= M28L; + x07 += (x06 >> 28); x06 &= M28L; + x08 += (x07 >> 28); x07 &= M28L; + x09 = (x08 >> 28); x08 &= M28L; + + x09 -= t; + + Debug.Assert(x09 == 0L || x09 == -1L); + + x00 += x09 & L0; + x01 += x09 & L1; + x02 += x09 & L2; + x03 += x09 & L3; + x04 += x09 & L4; + + x01 += (x00 >> 28); x00 &= M28L; + x02 += (x01 >> 28); x01 &= M28L; + x03 += (x02 >> 28); x02 &= M28L; + x04 += (x03 >> 28); x03 &= M28L; + x05 += (x04 >> 28); x04 &= M28L; + x06 += (x05 >> 28); x05 &= M28L; + x07 += (x06 >> 28); x06 &= M28L; + x08 += (x07 >> 28); x07 &= M28L; + + Codec.Encode56((ulong)(x00 | (x01 << 28)), r, 0); + Codec.Encode56((ulong)(x02 | (x03 << 28)), r, 7); + Codec.Encode56((ulong)(x04 | (x05 << 28)), r, 14); + Codec.Encode56((ulong)(x06 | (x07 << 28)), r, 21); + Codec.Encode32((uint)x08, r, 28); +#endif + + return r; + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void Reduce(ReadOnlySpan<byte> n, Span<byte> r) + { + long x00 = Codec.Decode32(n[ 0..]) & M32L; // x00:32/-- + long x01 = (Codec.Decode24(n[ 4..]) << 4) & M32L; // x01:28/-- + long x02 = Codec.Decode32(n[ 7..]) & M32L; // x02:32/-- + long x03 = (Codec.Decode24(n[11..]) << 4) & M32L; // x03:28/-- + long x04 = Codec.Decode32(n[14..]) & M32L; // x04:32/-- + long x05 = (Codec.Decode24(n[18..]) << 4) & M32L; // x05:28/-- + long x06 = Codec.Decode32(n[21..]) & M32L; // x06:32/-- + long x07 = (Codec.Decode24(n[25..]) << 4) & M32L; // x07:28/-- + long x08 = Codec.Decode32(n[28..]) & M32L; // x08:32/-- + long x09 = (Codec.Decode24(n[32..]) << 4) & M32L; // x09:28/-- + long x10 = Codec.Decode32(n[35..]) & M32L; // x10:32/-- + long x11 = (Codec.Decode24(n[39..]) << 4) & M32L; // x11:28/-- + long x12 = Codec.Decode32(n[42..]) & M32L; // x12:32/-- + long x13 = (Codec.Decode24(n[46..]) << 4) & M32L; // x13:28/-- + long x14 = Codec.Decode32(n[49..]) & M32L; // x14:32/-- + long x15 = (Codec.Decode24(n[53..]) << 4) & M32L; // x15:28/-- + long x16 = Codec.Decode32(n[56..]) & M32L; // x16:32/-- + long x17 = (Codec.Decode24(n[60..]) << 4) & M32L; // x17:28/-- + long x18 = n[63] & M08L; // x18:08/-- + long t; + + //x18 += (x17 >> 28); x17 &= M28L; + x09 -= x18 * L0; // x09:34/28 + x10 -= x18 * L1; // x10:33/30 + x11 -= x18 * L2; // x11:35/28 + x12 -= x18 * L3; // x12:32/31 + x13 -= x18 * L4; // x13:28/21 + + x17 += (x16 >> 28); x16 &= M28L; // x17:28/--, x16:28/-- + x08 -= x17 * L0; // x08:54/32 + x09 -= x17 * L1; // x09:52/51 + x10 -= x17 * L2; // x10:55/34 + x11 -= x17 * L3; // x11:51/36 + x12 -= x17 * L4; // x12:41/-- + + //x16 += (x15 >> 28); x15 &= M28L; + x07 -= x16 * L0; // x07:54/28 + x08 -= x16 * L1; // x08:54/53 + x09 -= x16 * L2; // x09:55/53 + x10 -= x16 * L3; // x10:55/52 + x11 -= x16 * L4; // x11:51/41 + + x15 += (x14 >> 28); x14 &= M28L; // x15:28/--, x14:28/-- + x06 -= x15 * L0; // x06:54/32 + x07 -= x15 * L1; // x07:54/53 + x08 -= x15 * L2; // x08:56/-- + x09 -= x15 * L3; // x09:55/54 + x10 -= x15 * L4; // x10:55/53 + + //x14 += (x13 >> 28); x13 &= M28L; + x05 -= x14 * L0; // x05:54/28 + x06 -= x14 * L1; // x06:54/53 + x07 -= x14 * L2; // x07:56/-- + x08 -= x14 * L3; // x08:56/51 + x09 -= x14 * L4; // x09:56/-- + + x13 += (x12 >> 28); x12 &= M28L; // x13:28/22, x12:28/-- + x04 -= x13 * L0; // x04:54/49 + x05 -= x13 * L1; // x05:54/53 + x06 -= x13 * L2; // x06:56/-- + x07 -= x13 * L3; // x07:56/52 + x08 -= x13 * L4; // x08:56/52 + + x12 += (x11 >> 28); x11 &= M28L; // x12:28/24, x11:28/-- + x03 -= x12 * L0; // x03:54/49 + x04 -= x12 * L1; // x04:54/51 + x05 -= x12 * L2; // x05:56/-- + x06 -= x12 * L3; // x06:56/52 + x07 -= x12 * L4; // x07:56/53 + + x11 += (x10 >> 28); x10 &= M28L; // x11:29/--, x10:28/-- + x02 -= x11 * L0; // x02:55/32 + x03 -= x11 * L1; // x03:55/-- + x04 -= x11 * L2; // x04:56/55 + x05 -= x11 * L3; // x05:56/52 + x06 -= x11 * L4; // x06:56/53 + + x10 += (x09 >> 28); x09 &= M28L; // x10:29/--, x09:28/-- + x01 -= x10 * L0; // x01:55/28 + x02 -= x10 * L1; // x02:55/54 + x03 -= x10 * L2; // x03:56/55 + x04 -= x10 * L3; // x04:57/-- + x05 -= x10 * L4; // x05:56/53 + + x08 += (x07 >> 28); x07 &= M28L; // x08:56/53, x07:28/-- + x09 += (x08 >> 28); x08 &= M28L; // x09:29/25, x08:28/-- + + t = (x08 >> 27) & 1L; + x09 += t; // x09:29/26 + + x00 -= x09 * L0; // x00:55/53 + x01 -= x09 * L1; // x01:55/54 + x02 -= x09 * L2; // x02:57/-- + x03 -= x09 * L3; // x03:57/-- + x04 -= x09 * L4; // x04:57/42 + + x01 += (x00 >> 28); x00 &= M28L; + x02 += (x01 >> 28); x01 &= M28L; + x03 += (x02 >> 28); x02 &= M28L; + x04 += (x03 >> 28); x03 &= M28L; + x05 += (x04 >> 28); x04 &= M28L; + x06 += (x05 >> 28); x05 &= M28L; + x07 += (x06 >> 28); x06 &= M28L; + x08 += (x07 >> 28); x07 &= M28L; + x09 = (x08 >> 28); x08 &= M28L; + + x09 -= t; + + Debug.Assert(x09 == 0L || x09 == -1L); + + x00 += x09 & L0; + x01 += x09 & L1; + x02 += x09 & L2; + x03 += x09 & L3; + x04 += x09 & L4; + + x01 += (x00 >> 28); x00 &= M28L; + x02 += (x01 >> 28); x01 &= M28L; + x03 += (x02 >> 28); x02 &= M28L; + x04 += (x03 >> 28); x03 &= M28L; + x05 += (x04 >> 28); x04 &= M28L; + x06 += (x05 >> 28); x05 &= M28L; + x07 += (x06 >> 28); x06 &= M28L; + x08 += (x07 >> 28); x07 &= M28L; + + Codec.Encode56((ulong)(x00 | (x01 << 28)), r); + Codec.Encode56((ulong)(x02 | (x03 << 28)), r[7..]); + Codec.Encode56((ulong)(x04 | (x05 << 28)), r[14..]); + Codec.Encode56((ulong)(x06 | (x07 << 28)), r[21..]); + Codec.Encode32((uint)x08, r[28..]); + } +#endif + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void ReduceBasisVar(ReadOnlySpan<uint> k, Span<uint> z0, Span<uint> z1) + { + /* + * Split scalar k into two half-size scalars z0 and z1, such that z1 * k == z0 mod L. + * + * See https://ia.cr/2020/454 (Pornin). + */ + + Span<uint> Nu = stackalloc uint[16]; LSq.CopyTo(Nu); + Span<uint> Nv = stackalloc uint[16]; Nat.Square(8, k, Nv); Nat.AddWordTo(16, 1U, Nv); + Span<uint> p = stackalloc uint[16]; Nat.Mul(8, L, k, p); + Span<uint> u0 = stackalloc uint[4]; u0.CopyFrom(L); + Span<uint> u1 = stackalloc uint[4]; + Span<uint> v0 = stackalloc uint[4]; v0.CopyFrom(k); + Span<uint> v1 = stackalloc uint[4]; v1[0] = 1U; + + int last = 15; + int len_Nv = GetBitLengthPositive(last, Nv); + + while (len_Nv > TargetLength) + { + int len_p = GetBitLength(last, p); + int s = len_p - len_Nv; + s &= ~(s >> 31); + + if ((int)p[last] < 0) + { + AddShifted_NP(last, s, Nu, Nv, p); + AddShifted_UV(3, s, u0, u1, v0, v1); + } + else + { + SubShifted_NP(last, s, Nu, Nv, p); + SubShifted_UV(3, s, u0, u1, v0, v1); + } + + if (LessThan(last, Nu, Nv)) + { + Swap(ref u0, ref v0); + Swap(ref u1, ref v1); + Swap(ref Nu, ref Nv); + + last = len_Nv >> 5; + len_Nv = GetBitLengthPositive(last, Nv); + } + } + + // v1 * k == v0 mod L + v0.CopyTo(z0); + v1.CopyTo(z1); + } +#else + internal static void ReduceBasisVar(uint[] k, uint[] z0, uint[] z1) + { + /* + * Split scalar k into two half-size scalars z0 and z1, such that z1 * k == z0 mod L. + * + * See https://ia.cr/2020/454 (Pornin). + */ + + uint[] Nu = new uint[16]; Array.Copy(LSq, Nu, 16); + uint[] Nv = new uint[16]; Nat.Square(8, k, Nv); Nat.AddWordTo(16, 1U, Nv); + uint[] p = new uint[16]; Nat.Mul(8, L, k, p); + uint[] u0 = new uint[4]; Array.Copy(L, u0, 4); + uint[] u1 = new uint[4]; + uint[] v0 = new uint[4]; Array.Copy(k, v0, 4); + uint[] v1 = new uint[4]; v1[0] = 1U; + + int last = 15; + int len_Nv = GetBitLengthPositive(last, Nv); + + while (len_Nv > TargetLength) + { + int len_p = GetBitLength(last, p); + int s = len_p - len_Nv; + s &= ~(s >> 31); + + if ((int)p[last] < 0) + { + AddShifted_NP(last, s, Nu, Nv, p); + AddShifted_UV(3, s, u0, u1, v0, v1); + } + else + { + SubShifted_NP(last, s, Nu, Nv, p); + SubShifted_UV(3, s, u0, u1, v0, v1); + } + + if (LessThan(last, Nu, Nv)) + { + Swap(ref u0, ref v0); + Swap(ref u1, ref v1); + Swap(ref Nu, ref Nv); + + last = len_Nv >> 5; + len_Nv = GetBitLengthPositive(last, Nv); + } + } + + // v1 * k == v0 mod L + Array.Copy(v0, z0, 4); + Array.Copy(v1, z1, 4); + } +#endif + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void ToSignedDigits(ReadOnlySpan<uint> x, Span<uint> z) +#else + internal static void ToSignedDigits(uint[] x, uint[] z) +#endif + { + uint c1 = Nat.CAdd(Size, ~(int)x[0] & 1, x, L, z); Debug.Assert(c1 == 0U); + uint c2 = Nat.ShiftDownBit(Size, z, 1U); Debug.Assert(c2 == (1U << 31)); + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static void AddShifted_NP(int last, int s, Span<uint> Nu, ReadOnlySpan<uint> Nv, Span<uint> _p) +#else + private static void AddShifted_NP(int last, int s, uint[] Nu, uint[] Nv, uint[] _p) +#endif + { + int sWords = s >> 5, sBits = s & 31; + + ulong cc__p = 0UL; + ulong cc_Nu = 0UL; + + if (sBits == 0) + { + for (int i = sWords; i <= last; ++i) + { + cc_Nu += Nu[i]; + cc_Nu += _p[i - sWords]; + + cc__p += _p[i]; + cc__p += Nv[i - sWords]; + _p[i] = (uint)cc__p; cc__p >>= 32; + + cc_Nu += _p[i - sWords]; + Nu[i] = (uint)cc_Nu; cc_Nu >>= 32; + } + } + else + { + uint prev_p = 0U; + uint prev_q = 0U; + uint prev_v = 0U; + + for (int i = sWords; i <= last; ++i) + { + uint next_p = _p[i - sWords]; + uint p_s = (next_p << sBits) | (prev_p >> -sBits); + prev_p = next_p; + + cc_Nu += Nu[i]; + cc_Nu += p_s; + + uint next_v = Nv[i - sWords]; + uint v_s = (next_v << sBits) | (prev_v >> -sBits); + prev_v = next_v; + + cc__p += _p[i]; + cc__p += v_s; + _p[i] = (uint)cc__p; cc__p >>= 32; + + uint next_q = _p[i - sWords]; + uint q_s = (next_q << sBits) | (prev_q >> -sBits); + prev_q = next_q; + + cc_Nu += q_s; + Nu[i] = (uint)cc_Nu; cc_Nu >>= 32; + } + } + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static void AddShifted_UV(int last, int s, Span<uint> u0, Span<uint> u1, ReadOnlySpan<uint> v0, + ReadOnlySpan<uint> v1) +#else + private static void AddShifted_UV(int last, int s, uint[] u0, uint[] u1, uint[] v0, uint[] v1) +#endif + { + int sWords = s >> 5, sBits = s & 31; + + ulong cc_u0 = 0UL; + ulong cc_u1 = 0UL; + + if (sBits == 0) + { + for (int i = sWords; i <= last; ++i) + { + cc_u0 += u0[i]; + cc_u1 += u1[i]; + cc_u0 += v0[i - sWords]; + cc_u1 += v1[i - sWords]; + u0[i] = (uint)cc_u0; cc_u0 >>= 32; + u1[i] = (uint)cc_u1; cc_u1 >>= 32; + } + } + else + { + uint prev_v0 = 0U; + uint prev_v1 = 0U; + + for (int i = sWords; i <= last; ++i) + { + uint next_v0 = v0[i - sWords]; + uint next_v1 = v1[i - sWords]; + uint v0_s = (next_v0 << sBits) | (prev_v0 >> -sBits); + uint v1_s = (next_v1 << sBits) | (prev_v1 >> -sBits); + prev_v0 = next_v0; + prev_v1 = next_v1; + + cc_u0 += u0[i]; + cc_u1 += u1[i]; + cc_u0 += v0_s; + cc_u1 += v1_s; + u0[i] = (uint)cc_u0; cc_u0 >>= 32; + u1[i] = (uint)cc_u1; cc_u1 >>= 32; + } + } + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static int GetBitLength(int last, ReadOnlySpan<uint> x) +#else + private static int GetBitLength(int last, uint[] x) +#endif + { + int i = last; + uint sign = (uint)((int)x[i] >> 31); + while (i > 0 && x[i] == sign) + { + --i; + } + return i * 32 + 32 - Integers.NumberOfLeadingZeros((int)(x[i] ^ sign)); + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static int GetBitLengthPositive(int last, ReadOnlySpan<uint> x) +#else + private static int GetBitLengthPositive(int last, uint[] x) +#endif + { + int i = last; + while (i > 0 && x[i] == 0) + { + --i; + } + return i * 32 + 32 - Integers.NumberOfLeadingZeros((int)x[i]); + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static bool LessThan(int last, ReadOnlySpan<uint> x, ReadOnlySpan<uint> y) +#else + private static bool LessThan(int last, uint[] x, uint[] y) +#endif + { + int i = last; + if ((int)x[i] < (int)y[i]) + return true; + if ((int)x[i] > (int)y[i]) + return false; + while (--i >= 0) + { + if (x[i] < y[i]) + return true; + if (x[i] > y[i]) + return false; + } + return false; + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static void SubShifted_NP(int last, int s, Span<uint> Nu, ReadOnlySpan<uint> Nv, Span<uint> _p) +#else + private static void SubShifted_NP(int last, int s, uint[] Nu, uint[] Nv, uint[] _p) +#endif + { + int sWords = s >> 5, sBits = s & 31; + + long cc__p = 0L; + long cc_Nu = 0L; + + if (sBits == 0) + { + for (int i = sWords; i <= last; ++i) + { + cc_Nu += Nu[i]; + cc_Nu -= _p[i - sWords]; + + cc__p += _p[i]; + cc__p -= Nv[i - sWords]; + _p[i] = (uint)cc__p; cc__p >>= 32; + + cc_Nu -= _p[i - sWords]; + Nu[i] = (uint)cc_Nu; cc_Nu >>= 32; + } + } + else + { + uint prev_p = 0U; + uint prev_q = 0U; + uint prev_v = 0U; + + for (int i = sWords; i <= last; ++i) + { + uint next_p = _p[i - sWords]; + uint p_s = (next_p << sBits) | (prev_p >> -sBits); + prev_p = next_p; + + cc_Nu += Nu[i]; + cc_Nu -= p_s; + + uint next_v = Nv[i - sWords]; + uint v_s = (next_v << sBits) | (prev_v >> -sBits); + prev_v = next_v; + + cc__p += _p[i]; + cc__p -= v_s; + _p[i] = (uint)cc__p; cc__p >>= 32; + + uint next_q = _p[i - sWords]; + uint q_s = (next_q << sBits) | (prev_q >> -sBits); + prev_q = next_q; + + cc_Nu -= q_s; + Nu[i] = (uint)cc_Nu; cc_Nu >>= 32; + } + } + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static void SubShifted_UV(int last, int s, Span<uint> u0, Span<uint> u1, ReadOnlySpan<uint> v0, + ReadOnlySpan<uint> v1) +#else + private static void SubShifted_UV(int last, int s, uint[] u0, uint[] u1, uint[] v0, uint[] v1) +#endif + { + int sWords = s >> 5, sBits = s & 31; + + long cc_u0 = 0L; + long cc_u1 = 0L; + + if (sBits == 0) + { + for (int i = sWords; i <= last; ++i) + { + cc_u0 += u0[i]; + cc_u1 += u1[i]; + cc_u0 -= v0[i - sWords]; + cc_u1 -= v1[i - sWords]; + u0[i] = (uint)cc_u0; cc_u0 >>= 32; + u1[i] = (uint)cc_u1; cc_u1 >>= 32; + } + } + else + { + uint prev_v0 = 0U; + uint prev_v1 = 0U; + + for (int i = sWords; i <= last; ++i) + { + uint next_v0 = v0[i - sWords]; + uint next_v1 = v1[i - sWords]; + uint v0_s = (next_v0 << sBits) | (prev_v0 >> -sBits); + uint v1_s = (next_v1 << sBits) | (prev_v1 >> -sBits); + prev_v0 = next_v0; + prev_v1 = next_v1; + + cc_u0 += u0[i]; + cc_u1 += u1[i]; + cc_u0 -= v0_s; + cc_u1 -= v1_s; + u0[i] = (uint)cc_u0; cc_u0 >>= 32; + u1[i] = (uint)cc_u1; cc_u1 >>= 32; + } + } + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + [MethodImpl(MethodImplOptions.AggressiveInlining)] + private static void Swap(ref Span<uint> x, ref Span<uint> y) +#else + private static void Swap(ref uint[] x, ref uint[] y) +#endif + { + var t = x; x = y; y = t; + } + } +} |