diff options
Diffstat (limited to 'crypto/src/math/raw/Interleave.cs')
| -rw-r--r-- | crypto/src/math/raw/Interleave.cs | 45 |
1 files changed, 37 insertions, 8 deletions
diff --git a/crypto/src/math/raw/Interleave.cs b/crypto/src/math/raw/Interleave.cs index 9ff85c572..c7c8eb4da 100644 --- a/crypto/src/math/raw/Interleave.cs +++ b/crypto/src/math/raw/Interleave.cs @@ -1,4 +1,5 @@ using System; +using System.Diagnostics; #if NETCOREAPP3_0_OR_GREATER using System.Runtime.Intrinsics.X86; #endif @@ -71,25 +72,53 @@ namespace Org.BouncyCastle.Math.Raw z[zOff + 1] = (x >> 1) & M64; } - internal static void Expand64To128(ulong[] zs, int zsOff, int zsLen) +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void Expand64To128(ulong x, Span<ulong> z) { - int i = zsLen, zsPos = zsOff + zsLen << 1; - while (--i >= 0) +#if NETCOREAPP3_0_OR_GREATER + if (Bmi2.X64.IsSupported) { - zsPos -= 2; - Expand64To128(zs[zsOff + i], zs, zsPos); + z[0] = Bmi2.X64.ParallelBitDeposit(x , 0x5555555555555555UL); + z[1] = Bmi2.X64.ParallelBitDeposit(x >> 32, 0x5555555555555555UL); + return; } +#endif + + // "shuffle" low half to even bits and high half to odd bits + x = Bits.BitPermuteStep(x, 0x00000000FFFF0000UL, 16); + x = Bits.BitPermuteStep(x, 0x0000FF000000FF00UL, 8); + x = Bits.BitPermuteStep(x, 0x00F000F000F000F0UL, 4); + x = Bits.BitPermuteStep(x, 0x0C0C0C0C0C0C0C0CUL, 2); + x = Bits.BitPermuteStep(x, 0x2222222222222222UL, 1); + + z[0] = (x ) & M64; + z[1] = (x >> 1) & M64; } +#endif internal static void Expand64To128(ulong[] xs, int xsOff, int xsLen, ulong[] zs, int zsOff) { - for (int i = 0; i < xsLen; ++i) + int xsPos = xsLen, zsPos = zsOff + xsLen << 1; + while (--xsPos >= 0) { - Expand64To128(xs[xsOff + i], zs, zsOff); - zsOff += 2; + zsPos -= 2; + Expand64To128(xs[xsOff + xsPos], zs, zsPos); } } +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + internal static void Expand64To128(ReadOnlySpan<ulong> xs, Span<ulong> zs) + { + int xsPos = xs.Length, zsPos = xs.Length << 1; + Debug.Assert(!zs[xsPos..zsPos].Overlaps(xs)); + while (--xsPos >= 0) + { + zsPos -= 2; + Expand64To128(xs[xsPos], zs[zsPos..]); + } + } +#endif + internal static ulong Expand64To128Rev(ulong x, out ulong low) { #if NETCOREAPP3_0_OR_GREATER |