diff options
Diffstat (limited to 'crypto/src/math/ec/Nat.cs')
| -rw-r--r-- | crypto/src/math/ec/Nat.cs | 68 |
1 files changed, 35 insertions, 33 deletions
diff --git a/crypto/src/math/ec/Nat.cs b/crypto/src/math/ec/Nat.cs index 599d929c2..1ddcb1609 100644 --- a/crypto/src/math/ec/Nat.cs +++ b/crypto/src/math/ec/Nat.cs @@ -32,18 +32,19 @@ namespace Org.BouncyCastle.Math.EC return (uint)c; } - //public static uint AddDWord(int len, ulong x, uint[] z, int zOff) - //{ - // Debug.Assert(zOff < (len - 2)); - // ulong c = x; - // c += (ulong)z[zOff + 0]; - // z[zOff + 0] = (uint)c; - // c >>= 32; - // c += (ulong)z[zOff + 1]; - // z[zOff + 1] = (uint)c; - // c >>= 32; - // return c == 0 ? 0 : Inc(len, z, zOff + 2); - //} + // TODO Re-write to allow full range for x? + public static uint AddDWord(int len, ulong x, uint[] z, int zOff) + { + Debug.Assert(zOff <= (len - 2)); + ulong c = x; + c += (ulong)z[zOff + 0]; + z[zOff + 0] = (uint)c; + c >>= 32; + c += (ulong)z[zOff + 1]; + z[zOff + 1] = (uint)c; + c >>= 32; + return c == 0 ? 0 : Inc(len, z, zOff + 2); + } public static uint AddExt(int len, uint[] xx, uint[] yy, uint[] zz) { @@ -73,7 +74,8 @@ namespace Org.BouncyCastle.Math.EC public static uint AddWordExt(int len, uint x, uint[] zz, int zzOff) { - Debug.Assert(zzOff < ((len << 1) - 1)); + int extLen = len << 1; + Debug.Assert(zzOff <= (extLen - 1)); ulong c = (ulong)x + zz[zzOff]; zz[zzOff] = (uint)c; c >>= 32; @@ -100,16 +102,14 @@ namespace Org.BouncyCastle.Math.EC public static int Dec(int len, uint[] z, int zOff) { - Debug.Assert(zOff < len); - int i = zOff; - do + Debug.Assert(zOff <= len); + for (int i = zOff; i < len; ++i) { if (--z[i] != uint.MaxValue) { return 0; } } - while (++i < len); return -1; } @@ -172,10 +172,10 @@ namespace Org.BouncyCastle.Math.EC public static uint Inc(int len, uint[] z, int zOff) { - Debug.Assert(zOff < len); + Debug.Assert(zOff <= len); for (int i = zOff; i < len; ++i) { - if (++z[i] != 0) + if (++z[i] != uint.MinValue) { return 0; } @@ -186,10 +186,10 @@ namespace Org.BouncyCastle.Math.EC public static uint IncExt(int len, uint[] zz, int zzOff) { int extLen = len; - Debug.Assert(zzOff < extLen); + Debug.Assert(zzOff <= extLen); for (int i = zzOff; i < extLen; ++i) { - if (++zz[i] != 0) + if (++zz[i] != uint.MinValue) { return 0; } @@ -274,7 +274,7 @@ namespace Org.BouncyCastle.Math.EC public static uint MulWordDwordAdd(int len, uint x, ulong y, uint[] z, int zOff) { - Debug.Assert(zOff < (len - 3)); + Debug.Assert(zOff <= (len - 3)); ulong c = 0, xVal = (ulong)x; c += xVal * (uint)y + z[zOff + 0]; z[zOff + 0] = (uint)c; @@ -437,17 +437,19 @@ namespace Org.BouncyCastle.Math.EC return (int)c; } - //public static int SubDWord(int len, ulong x, uint[] z) - //{ - // long c = -(long)x; - // c += (long)z[0]; - // z[0] = (uint)c; - // c >>= 32; - // c += (long)z[1]; - // z[1] = (uint)c; - // c >>= 32; - // return c == 0 ? 0 : Dec(len, z, 2); - //} + // TODO Re-write to allow full range for x? + public static int SubDWord(int len, ulong x, uint[] z) + { + Debug.Assert(len >= 2); + long c = -(long)x; + c += (long)z[0]; + z[0] = (uint)c; + c >>= 32; + c += (long)z[1]; + z[1] = (uint)c; + c >>= 32; + return c == 0 ? 0 : Dec(len, z, 2); + } public static int SubExt(int len, uint[] xx, uint[] yy, uint[] zz) { |