feature: .NET 10 (ryubing/ryujinx!214)

See merge request ryubing/ryujinx!214

src/ARMeilleure/Instructions/SoftFallback/SoftFallback.Count.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace ARMeilleure.Instructions
+{
+    static partial class SoftFallback
+    {
+        [UnmanagedCallersOnly]
+        public static ulong CountLeadingSigns(ulong value, int size) // size is 8, 16, 32 or 64 (SIMD&FP or Base Inst.).
+        {
+            value ^= value >> 1;
+
+            int highBit = size - 2;
+
+            for (int bit = highBit; bit >= 0; bit--)
+            {
+                if (((int)(value >> bit) & 0b1) != 0)
+                {
+                    return (ulong)(highBit - bit);
+                }
+            }
+
+            return (ulong)(size - 1);
+        }
+
+        private static ReadOnlySpan<byte> ClzNibbleTbl => [4, 3, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0];
+
+        [UnmanagedCallersOnly]
+        public static ulong CountLeadingZeros(ulong value, int size) // size is 8, 16, 32 or 64 (SIMD&FP or Base Inst.).
+        {
+            if (value == 0ul)
+            {
+                return (ulong)size;
+            }
+
+            int nibbleIdx = size;
+            int preCount, count = 0;
+
+            do
+            {
+                nibbleIdx -= 4;
+                preCount = ClzNibbleTbl[(int)(value >> nibbleIdx) & 0b1111];
+                count += preCount;
+            }
+            while (preCount == 4);
+
+            return (ulong)count;
+        }
+    }
+}