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| author | Peter Dettman <peter.dettman@bouncycastle.org> | 2015-12-28 14:59:52 +0700 |
|---|---|---|
| committer | Peter Dettman <peter.dettman@bouncycastle.org> | 2015-12-28 14:59:52 +0700 |
| commit | 125e93ac90fab535316f55695f14dde8e9c76c97 (patch) | |
| tree | 2dff432202163117d5012448b977c87c6f44a218 /crypto/src/math/raw/Interleave.cs | |
| parent | XML doc for TlsClient.ClientHelloRecordLayerVersion (diff) | |
| download | BouncyCastle.NET-ed25519-125e93ac90fab535316f55695f14dde8e9c76c97.tar.xz | |
Optimized Sqrt and Trace for custom binary curves
Diffstat (limited to 'crypto/src/math/raw/Interleave.cs')
| -rw-r--r-- | crypto/src/math/raw/Interleave.cs | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/crypto/src/math/raw/Interleave.cs b/crypto/src/math/raw/Interleave.cs index a45ee1e08..d21840644 100644 --- a/crypto/src/math/raw/Interleave.cs +++ b/crypto/src/math/raw/Interleave.cs @@ -91,5 +91,17 @@ namespace Org.BouncyCastle.Math.Raw z[zOff ] = (x ) & M64; z[zOff + 1] = (x >> 1) & M64; } + + internal static ulong Unshuffle(ulong x) + { + // "unshuffle" even bits to low half and odd bits to high half + ulong t; + t = (x ^ (x >> 1)) & 0x2222222222222222UL; x ^= (t ^ (t << 1)); + t = (x ^ (x >> 2)) & 0x0C0C0C0C0C0C0C0CUL; x ^= (t ^ (t << 2)); + t = (x ^ (x >> 4)) & 0x00F000F000F000F0UL; x ^= (t ^ (t << 4)); + t = (x ^ (x >> 8)) & 0x0000FF000000FF00UL; x ^= (t ^ (t << 8)); + t = (x ^ (x >> 16)) & 0x00000000FFFF0000UL; x ^= (t ^ (t << 16)); + return x; + } } } |