Reapply modulo helpers and inline fast remainders

PerfectNumbers.Core/UIntExtensions.cs

@@ -4,57 +4,74 @@ namespace PerfectNumbers.Core;
 
 public static class UIntExtensions
 {
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod3(this uint value) => PerfectNumbersMath.FastRemainder3(value);
+    private static readonly byte[] Mod6Lookup = { 0, 3, 4, 1, 2, 5 };
 
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod5(this uint value) => PerfectNumbersMath.FastRemainder5(value);
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod3(this uint value)
+    {
+        uint quotient = (uint)(((ulong)value * 0xAAAAAAABUL) >> 33);
+        return value - quotient * 3U;
+    }
 
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod7(this uint value)
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod5(this uint value)
+    {
+        uint quotient = (uint)(((ulong)value * 0xCCCCCCCDUL) >> 34);
+        return value - quotient * 5U;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod6(this uint value)
+    {
+        uint key = (value.Mod3() << 1) | (value & 1U);
+        return Mod6Lookup[(int)key];
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod7(this uint value)
+    {
+        uint remainder = 0U;
+        uint temp = value;
+
+        while (temp != 0U)
         {
-                uint remainder = 0U;
-                uint temp = value;
-
-                while (temp != 0U)
-                {
-                        remainder += temp & 7U;
-                        temp >>= 3;
-                        if (remainder >= 7U)
-                        {
-                                remainder -= 7U;
-                        }
-                }
-
-                return remainder >= 7U ? remainder - 7U : remainder;
+            remainder += temp & 7U;
+            temp >>= 3;
+            if (remainder >= 7U)
+            {
+                remainder -= 7U;
+            }
         }
 
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod8(this uint value) => value & 7U;
+        return remainder >= 7U ? remainder - 7U : remainder;
+    }
 
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod10(this uint value)
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod8(this uint value) => value & 7U;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod10(this uint value)
+    {
+        return value - (uint)(((ulong)value * 0xCCCCCCCDUL) >> 35) * 10U;
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod11(this uint value)
+    {
+        uint remainder = 0U;
+        uint temp = value;
+
+        while (temp != 0U)
         {
-                return value - (uint)(((ulong)value * 0xCCCCCCCDUL) >> 35) * 10U;
+            remainder += temp & 1023U;
+            temp >>= 10;
+            remainder -= 11U * (remainder / 11U);
         }
 
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod11(this uint value)
-        {
-                uint remainder = 0U;
-                uint temp = value;
+        return remainder;
+    }
 
-                while (temp != 0U)
-                {
-                        remainder += temp & 1023U;
-                        temp >>= 10;
-                        remainder -= 11U * (remainder / 11U);
-                }
-
-                return remainder;
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Mod128(this uint value) => value & 127U;
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Mod128(this uint value) => value & 127U;
 }