1 files changed, 42 insertions, 0 deletions
diff --git a/ARMeilleure/Decoders/OpCodeT16MemStack.cs b/ARMeilleure/Decoders/OpCodeT16MemStack.cs
new file mode 100644
index 00000000..9d7b0d20
--- /dev/null
+++ b/ARMeilleure/Decoders/OpCodeT16MemStack.cs
@@ -0,0 +1,42 @@
+using ARMeilleure.Instructions;
+using ARMeilleure.State;
+using System;
+using System.Numerics;
+
+namespace ARMeilleure.Decoders
+{
+    class OpCodeT16MemStack : OpCodeT16, IOpCode32MemMult
+    {
+        public int Rn => RegisterAlias.Aarch32Sp;
+        public int RegisterMask { get; }
+        public int PostOffset { get; }
+        public bool IsLoad { get; }
+        public int Offset { get; }
+
+        public new static OpCode Create(InstDescriptor inst, ulong address, int opCode) => new OpCodeT16MemStack(inst, address, opCode);
+
+        public OpCodeT16MemStack(InstDescriptor inst, ulong address, int opCode) : base(inst, address, opCode)
+        {
+            int extra = (opCode >> 8) & 1;
+            int regCount = BitOperations.PopCount((uint)opCode & 0x1ff);
+
+            switch (inst.Name)
+            {
+                case InstName.Push:
+                    RegisterMask = (opCode & 0xff) | (extra << 14);
+                    IsLoad = false;
+                    Offset = -4 * regCount;
+                    PostOffset = -4 * regCount;
+                    break;
+                case InstName.Pop:
+                    RegisterMask = (opCode & 0xff) | (extra << 15);
+                    IsLoad = true;
+                    Offset = 0;
+                    PostOffset = 4 * regCount;
+                    break;
+                default:
+                    throw new InvalidOperationException();
+            }
+        }
+    }
+}