Add Cls Instruction. (#67)

* Update AInstEmitAlu.cs

* Update ASoftFallback.cs

* Update AOpCodeTable.cs

2 files changed, 28 insertions, 2 deletions

diff --git a/ChocolArm64/Instruction/AInstEmitAlu.cs b/ChocolArm64/Instruction/AInstEmitAlu.cs
index 57020364..bacbfc9e 100644
--- a/ChocolArm64/Instruction/AInstEmitAlu.cs
+++ b/ChocolArm64/Instruction/AInstEmitAlu.cs
@@ -100,6 +100,24 @@ namespace ChocolArm64.Instruction
             EmitDataStore(Context, SetFlags);
         }
 
+        public static void Cls(AILEmitterCtx Context)
+        {
+            AOpCodeAlu Op = (AOpCodeAlu)Context.CurrOp;
+
+            Context.EmitLdintzr(Op.Rn);
+
+            if (Op.RegisterSize == ARegisterSize.Int32)
+            {
+                ASoftFallback.EmitCall(Context, nameof(ASoftFallback.CountLeadingSigns32));
+            }
+            else
+            {
+                ASoftFallback.EmitCall(Context, nameof(ASoftFallback.CountLeadingSigns64));
+            }
+
+            Context.EmitStintzr(Op.Rd);
+        }
+
         public static void Clz(AILEmitterCtx Context)
         {
             AOpCodeAlu Op = (AOpCodeAlu)Context.CurrOp;
@@ -383,4 +401,4 @@ namespace ChocolArm64.Instruction
             Context.EmitStflg((int)APState.CBit);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/ChocolArm64/Instruction/ASoftFallback.cs b/ChocolArm64/Instruction/ASoftFallback.cs
index 705ca4a2..c0594413 100644
--- a/ChocolArm64/Instruction/ASoftFallback.cs
+++ b/ChocolArm64/Instruction/ASoftFallback.cs
@@ -20,6 +20,14 @@ namespace ChocolArm64.Instruction
             Context.EmitCall(typeof(ASoftFallback), MthdName);
         }
 
+        public static uint  CountLeadingSigns32(uint Value)  => (uint)CountLeadingSigns(Value, 32);
+        public static ulong CountLeadingSigns64(ulong Value) => (ulong)CountLeadingSigns(Value, 64);
+
+        private static ulong CountLeadingSigns(ulong Value, int Size)
+        {
+            return CountLeadingZeros((Value >> 1) ^ Value, Size - 1);
+        }
+
         public static uint  CountLeadingZeros32(uint Value)  => (uint)CountLeadingZeros(Value, 32);
         public static ulong CountLeadingZeros64(ulong Value) => (ulong)CountLeadingZeros(Value, 64);
 
@@ -398,4 +406,4 @@ namespace ChocolArm64.Instruction
             throw new ArgumentOutOfRangeException(nameof(Size));
         }
     }
-}
\ No newline at end of file
+}