diff options
| -rw-r--r-- | crypto/src/math/raw/Mod.cs | 79 |
1 files changed, 33 insertions, 46 deletions
diff --git a/crypto/src/math/raw/Mod.cs b/crypto/src/math/raw/Mod.cs index 721134b0c..f1ca2ebf0 100644 --- a/crypto/src/math/raw/Mod.cs +++ b/crypto/src/math/raw/Mod.cs @@ -105,11 +105,6 @@ namespace Org.BouncyCastle.Math.Raw int signF = F[len30 - 1] >> 31; CNegate30(len30, signF, F); - /* - * D is in the range (-2.M, M). First, conditionally add M if D is negative, to bring it - * into the range (-M, M). Then normalize by conditionally negating (according to signF) - * and/or then adding M, to bring it into the range [0, M). - */ CNormalize30(len30, signF, D, M); Decode30(bits, D, 0, z, 0); @@ -160,11 +155,6 @@ namespace Org.BouncyCastle.Math.Raw int signF = F[len30 - 1] >> 31; CNegate30(len30, signF, F); - /* - * D is in the range (-2.M, M). First, conditionally add M if D is negative, to bring it - * into the range (-M, M). Then normalize by conditionally negating (according to signF) - * and/or then adding M, to bring it into the range [0, M). - */ CNormalize30(len30, signF, D, M); Decode30(bits, D, z); @@ -206,7 +196,7 @@ namespace Org.BouncyCastle.Math.Raw int maxDivsteps = GetMaximumDivsteps(bits); int divsteps = 0; - while (!IsZero(lenFG, G)) + while (!EqualToZeroVar_Unlikely(lenFG, G)) { if (divsteps >= maxDivsteps) return false; @@ -251,7 +241,7 @@ namespace Org.BouncyCastle.Math.Raw } Debug.Assert(0 == signF); - if (!IsOne(lenFG, F)) + if (!EqualToOneVar_Expected(lenFG, F)) return false; if (signD < 0) @@ -301,7 +291,7 @@ namespace Org.BouncyCastle.Math.Raw int maxDivsteps = GetMaximumDivsteps(bits); int divsteps = 0; - while (!IsZero(lenFG, G)) + while (!EqualToZeroVar_Unlikely(lenFG, G)) { if (divsteps >= maxDivsteps) return false; @@ -346,7 +336,7 @@ namespace Org.BouncyCastle.Math.Raw } Debug.Assert(0 == signF); - if (!IsOne(lenFG, F)) + if (!EqualToOneVar_Expected(lenFG, F)) return false; if (signD < 0) @@ -466,6 +456,12 @@ namespace Org.BouncyCastle.Math.Raw Debug.Assert(D.Length >= len30); Debug.Assert(M.Length >= len30); + /* + * D is in the range (-2.M, M). First, conditionally add M if D is negative, to bring it + * into the range (-M, M). Then normalize by conditionally negating (according to signF) + * and/or then adding M, to bring it into the range [0, M). + */ + int last = len30 - 1; { @@ -717,6 +713,20 @@ namespace Org.BouncyCastle.Math.Raw } #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + private static bool EqualToOneVar_Expected(int len, ReadOnlySpan<int> x) +#else + private static bool EqualToOneVar_Expected(int len, int[] x) +#endif + { + int d = x[0] ^ 1; + for (int i = 1; i < len; ++i) + { + d |= x[i]; + } + return d == 0; + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER private static int EqualToZero(int len, ReadOnlySpan<int> x) #else private static int EqualToZero(int len, int[] x) @@ -731,49 +741,26 @@ namespace Org.BouncyCastle.Math.Raw return (d - 1) >> 31; } - private static int GetMaximumDivsteps(int bits) - { - return (49 * bits + (bits < 46 ? 80 : 47)) / 17; - } - #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER - private static bool IsOne(int len, ReadOnlySpan<int> x) + private static bool EqualToZeroVar_Unlikely(int len, ReadOnlySpan<int> x) #else - private static bool IsOne(int len, int[] x) + private static bool EqualToZeroVar_Unlikely(int len, int[] x) #endif { - if (x[0] != 1) - { + int d = x[0]; + if (d != 0) return false; - } + for (int i = 1; i < len; ++i) { - if (x[i] != 0) - { - return false; - } + d |= x[i]; } - return true; + return d == 0; } -#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER - private static bool IsZero(int len, ReadOnlySpan<int> x) -#else - private static bool IsZero(int len, int[] x) -#endif + private static int GetMaximumDivsteps(int bits) { - if (x[0] != 0) - { - return false; - } - for (int i = 1; i < len; ++i) - { - if (x[i] != 0) - { - return false; - } - } - return true; + return (49 * bits + (bits < 46 ? 80 : 47)) / 17; } #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER |