Implement some ARM32 memory instructions and CMP (#565)

* Implement ARM32 memory instructions: LDM, LDR, LDRB, LDRD, LDRH, LDRSB, LDRSH, STM, STR, STRB, STRD, STRH (immediate and register + immediate variants), implement CMP (immediate and register shifted by immediate variants)

* Rename some opcode classes and flag masks for consistency

* Fix a few suboptimal ARM32 codegen issues, only loads should be considered on decoder when checking if Rt == PC, and only NZCV flags should be considered for comparison optimizations

* Take into account Rt2 for LDRD instructions aswell when checking if the instruction changes PC

* Re-align arm32 instructions on the opcode table

1 files changed, 37 insertions, 0 deletions

diff --git a/ChocolArm64/Decoders/OpCode32Mem.cs b/ChocolArm64/Decoders/OpCode32Mem.cs
new file mode 100644
index 00000000..ed648a5f
--- /dev/null
+++ b/ChocolArm64/Decoders/OpCode32Mem.cs
@@ -0,0 +1,37 @@
+using ChocolArm64.Instructions;
+
+namespace ChocolArm64.Decoders
+{
+    class OpCode32Mem : OpCode32, IOpCode32Mem
+    {
+        public int  Rt { get; private set; }
+        public int  Rn { get; private set; }
+
+        public int Imm { get; protected set; }
+
+        public bool Index        { get; private set; }
+        public bool Add          { get; private set; }
+        public bool WBack        { get; private set; }
+        public bool Unprivileged { get; private set; }
+
+        public bool IsLoad { get; private set; }
+
+        public OpCode32Mem(Inst inst, long position, int opCode) : base(inst, position, opCode)
+        {
+            Rt = (opCode >> 12) & 0xf;
+            Rn = (opCode >> 16) & 0xf;
+
+            bool isLoad = (opCode & (1 << 20)) != 0;
+            bool w      = (opCode & (1 << 21)) != 0;
+            bool u      = (opCode & (1 << 23)) != 0;
+            bool p      = (opCode & (1 << 24)) != 0;
+
+            Index        = p;
+            Add          = u;
+            WBack        = !p || w;
+            Unprivileged = !p && w;
+
+            IsLoad = isLoad || inst.Emitter == InstEmit32.Ldrd;
+        }
+    }
+}
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