From f693a6cd892ea8a4747d5cff60ad2051458ad5f5 Mon Sep 17 00:00:00 2001
From: Peter Dettman <peter.dettman@bouncycastle.org>
Date: Thu, 1 Dec 2022 00:58:27 +0700
Subject: Tnaf perf. opts.

---
 crypto/src/math/raw/Nat.cs | 49 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 47 insertions(+), 2 deletions(-)

(limited to 'crypto/src/math/raw')

diff --git a/crypto/src/math/raw/Nat.cs b/crypto/src/math/raw/Nat.cs
index 4600f247f..fa76f305e 100644
--- a/crypto/src/math/raw/Nat.cs
+++ b/crypto/src/math/raw/Nat.cs
@@ -14,7 +14,7 @@ namespace Org.BouncyCastle.Math.Raw
 
         public static uint Add(int len, uint[] x, uint[] y, uint[] z)
         {
-            ulong c = 0;
+            ulong c = 0UL;
             for (int i = 0; i < len; ++i)
             {
                 c += (ulong)x[i] + y[i];
@@ -27,7 +27,7 @@ namespace Org.BouncyCastle.Math.Raw
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
         public static uint Add(int len, ReadOnlySpan<uint> x, ReadOnlySpan<uint> y, Span<uint> z)
         {
-            ulong c = 0;
+            ulong c = 0UL;
             for (int i = 0; i < len; ++i)
             {
                 c += (ulong)x[i] + y[i];
@@ -1398,6 +1398,32 @@ namespace Org.BouncyCastle.Math.Raw
         }
 #endif
 
+        public static int Negate(int len, uint[] x, uint[] z)
+        {
+            long c = 0L;
+            for (int i = 0; i < len; ++i)
+            {
+                c -= x[i];
+                z[i] = (uint)c;
+                c >>= 32;
+            }
+            return (int)c;
+        }
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        public static int Negate(int len, ReadOnlySpan<uint> x, Span<uint> z)
+        {
+            long c = 0L;
+            for (int i = 0; i < len; ++i)
+            {
+                c -= x[i];
+                z[i] = (uint)c;
+                c >>= 32;
+            }
+            return (int)c;
+        }
+#endif
+
         public static uint ShiftDownBit(int len, uint[] z, uint c)
         {
             int i = len;
@@ -2610,6 +2636,25 @@ namespace Org.BouncyCastle.Math.Raw
         }
 #endif
 
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+        public static int SubInt32From(int len, int x, Span<uint> z)
+        {
+            long c = (long)z[0] - x;
+            z[0] = (uint)c;
+            c >>= 32;
+
+            int i = 1;
+            while (c != 0L && i < len)
+            {
+                c += z[i];
+                z[i++] = (uint)c;
+                c >>= 32;
+            }
+
+            return (int)c;
+        }
+#endif
+
         public static int SubWordAt(int len, uint x, uint[] z, int zPos)
         {
             Debug.Assert(zPos <= (len - 1));
-- 
cgit 1.5.1