diff options
Diffstat (limited to 'crypto/src/math/raw/Interleave.cs')
| -rw-r--r-- | crypto/src/math/raw/Interleave.cs | 86 |
1 files changed, 75 insertions, 11 deletions
diff --git a/crypto/src/math/raw/Interleave.cs b/crypto/src/math/raw/Interleave.cs index 17351d002..8082ce57c 100644 --- a/crypto/src/math/raw/Interleave.cs +++ b/crypto/src/math/raw/Interleave.cs @@ -175,7 +175,7 @@ namespace Org.BouncyCastle.Math.Raw internal static ulong Shuffle(ulong x) { #if NETCOREAPP3_0_OR_GREATER - if (Bmi2.IsSupported) + if (Bmi2.X64.IsSupported) { return Bmi2.X64.ParallelBitDeposit(x >> 32, 0xAAAAAAAAAAAAAAAAUL) | Bmi2.X64.ParallelBitDeposit(x , 0x5555555555555555UL); @@ -203,11 +203,39 @@ namespace Org.BouncyCastle.Math.Raw } #endif - // "shuffle" (twice) low half to even bits and high half to odd bits - x = Bits.BitPermuteStep(x, 0x00AA00AAU, 7); - x = Bits.BitPermuteStep(x, 0x0000CCCCU, 14); - x = Bits.BitPermuteStep(x, 0x00F000F0U, 4); - x = Bits.BitPermuteStep(x, 0x0000FF00U, 8); + // 4 3 2 1 0 => 2 1 4 3 0 + x = Bits.BitPermuteStep(x, 0x0000F0F0U, 12); + x = Bits.BitPermuteStep(x, 0x00CC00CCU, 6); + + // 2 1 4 3 0 => 2 1 4 0 3 + x = Bits.BitPermuteStep(x, 0x22222222U, 1); + + // 2 1 4 0 3 => 2 1 0 4 3 + x = Bits.BitPermuteStep(x, 0x0C0C0C0CU, 2); + + return x; + } + + internal static ulong Shuffle2(ulong x) + { +#if NETCOREAPP3_0_OR_GREATER + if (Bmi2.X64.IsSupported) + { + return Bmi2.X64.ParallelBitDeposit(x >> 48, 0x8888888888888888UL) + | Bmi2.X64.ParallelBitDeposit(x >> 32, 0x4444444444444444UL) + | Bmi2.X64.ParallelBitDeposit(x >> 16, 0x2222222222222222UL) + | Bmi2.X64.ParallelBitDeposit(x , 0x1111111111111111UL); + } +#endif + + // 5 4 3 2 1 0 => 3 2 5 4 1 0 + x = Bits.BitPermuteStep(x, 0x00000000FF00FF00UL, 24); + x = Bits.BitPermuteStep(x, 0x0000F0F00000F0F0UL, 12); + + // 3 2 5 4 1 0 => 3 2 1 0 5 4 + x = Bits.BitPermuteStep(x, 0x00CC00CC00CC00CCUL, 6); + x = Bits.BitPermuteStep(x, 0x0A0A0A0A0A0A0A0AUL, 3); + return x; } @@ -293,11 +321,47 @@ namespace Org.BouncyCastle.Math.Raw } #endif - // "unshuffle" (twice) even bits to low half and odd bits to high half - x = Bits.BitPermuteStep(x, 0x0000FF00U, 8); - x = Bits.BitPermuteStep(x, 0x00F000F0U, 4); - x = Bits.BitPermuteStep(x, 0x0000CCCCU, 14); - x = Bits.BitPermuteStep(x, 0x00AA00AAU, 7); + // 4 3 2 1 0 => 4 3 1 2 0 + x = Bits.BitPermuteStep(x, 0x0C0C0C0CU, 2); + + // 4 3 1 2 0 => 4 3 1 0 2 + x = Bits.BitPermuteStep(x, 0x22222222U, 1); + + // 4 3 1 0 2 => 1 0 4 3 2 + x = Bits.BitPermuteStep(x, 0x0000F0F0U, 12); + x = Bits.BitPermuteStep(x, 0x00CC00CCU, 6); + + return x; + } + + internal static ulong Unshuffle2(ulong x) + { +#if NETCOREAPP3_0_OR_GREATER + if (Bmi2.X64.IsSupported) + { + return Bmi2.X64.ParallelBitExtract(x, 0x8888888888888888UL) << 48 + | Bmi2.X64.ParallelBitExtract(x, 0x4444444444444444UL) << 32 + | Bmi2.X64.ParallelBitExtract(x, 0x2222222222222222UL) << 16 + | Bmi2.X64.ParallelBitExtract(x, 0x1111111111111111UL); + } +#endif + + // 5 4 3 2 1 0 => 5 4 1 0 3 2 + x = Bits.BitPermuteStep(x, 0x00CC00CC00CC00CCUL, 6); + x = Bits.BitPermuteStep(x, 0x0A0A0A0A0A0A0A0AUL, 3); + + // 5 4 1 0 3 2 => 1 0 5 4 3 2 + x = Bits.BitPermuteStep(x, 0x00000000FF00FF00UL, 24); + x = Bits.BitPermuteStep(x, 0x0000F0F00000F0F0UL, 12); + + return x; + } + + internal static ulong Transpose(ulong x) + { + x = Bits.BitPermuteStep(x, 0x00000000F0F0F0F0UL, 28); + x = Bits.BitPermuteStep(x, 0x0000CCCC0000CCCCUL, 14); + x = Bits.BitPermuteStep(x, 0x00AA00AA00AA00AAUL, 7); return x; } } |