From 9c16e8695b07574a08cdae40e832122eb7f7a685 Mon Sep 17 00:00:00 2001
From: merry <git@mary.rs>
Date: Fri, 11 Feb 2022 21:23:08 +0000
Subject: [PATCH] T16: Implement LDM, STM

---
 ARMeilleure/Decoders/OpCodeT16MemMult.cs | 41 ++++++++++++++++++++++++
 ARMeilleure/Decoders/OpCodeTable.cs      |  2 ++
 2 files changed, 43 insertions(+)
 create mode 100644 ARMeilleure/Decoders/OpCodeT16MemMult.cs

diff --git a/ARMeilleure/Decoders/OpCodeT16MemMult.cs b/ARMeilleure/Decoders/OpCodeT16MemMult.cs
new file mode 100644
index 000000000..b0fd11c0a
--- /dev/null
+++ b/ARMeilleure/Decoders/OpCodeT16MemMult.cs
@@ -0,0 +1,41 @@
+using ARMeilleure.Instructions;
+using System;
+using System.Numerics;
+
+namespace ARMeilleure.Decoders
+{
+    class OpCodeT16MemMult : OpCodeT16, IOpCode32MemMult
+    {
+        public int Rn { get; }
+        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, bool inITBlock) => new OpCodeT16MemMult(inst, address, opCode, inITBlock);
+
+        public OpCodeT16MemMult(InstDescriptor inst, ulong address, int opCode, bool inITBlock) : base(inst, address, opCode, inITBlock)
+        {
+            RegisterMask = opCode & 0xff;
+            Rn = (opCode >> 8) & 7;
+            
+            int regCount = BitOperations.PopCount((uint)RegisterMask);
+            
+            switch (inst.Name)
+            {
+                case InstName.Stm:
+                    IsLoad = false;
+                    Offset = 0;
+                    PostOffset = 4 * regCount;
+                    break;
+                case InstName.Ldm:
+                    IsLoad = true;
+                    Offset = 0;
+                    PostOffset = 4 * regCount;
+                    break;
+                default:
+                    throw new InvalidOperationException();
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/ARMeilleure/Decoders/OpCodeTable.cs b/ARMeilleure/Decoders/OpCodeTable.cs
index 4f99e26ce..c62147422 100644
--- a/ARMeilleure/Decoders/OpCodeTable.cs
+++ b/ARMeilleure/Decoders/OpCodeTable.cs
@@ -1037,6 +1037,8 @@ namespace ARMeilleure.Decoders
             SetT16("101110x1xxxxxxxx", InstName.Cbnz,   InstEmit32.Cbnz,    OpCodeT16BImmCmp.Create);
             SetT16("1011110xxxxxxxxx", InstName.Pop,    InstEmit32.Ldm,     OpCodeT16MemStack.Create);
             SetT16("10111111xxxx0000", InstName.Nop,    InstEmit32.Nop,     OpCodeT16.Create);
+            SetT16("11000xxxxxxxxxxx", InstName.Stm,    InstEmit32.Stm,     OpCodeT16MemMult.Create);
+            SetT16("11001xxxxxxxxxxx", InstName.Ldm,    InstEmit32.Ldm,     OpCodeT16MemMult.Create);
             #endregion
 
             FillFastLookupTable(InstA32FastLookup, AllInstA32, ToFastLookupIndexA);