From cffa8905ab9c5e006d21b658188b110941d00c43 Mon Sep 17 00:00:00 2001
From: merry <git@mary.rs>
Date: Tue, 8 Feb 2022 19:00:47 +0000
Subject: [PATCH] ARMeilleure: Add debuggable CPU loop

---
 ARMeilleure/Optimizations.cs                 |  1 +
 ARMeilleure/Translation/ArmEmitterContext.cs |  2 +-
 ARMeilleure/Translation/Translator.cs        | 33 +++++++++++++++++---
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/ARMeilleure/Optimizations.cs b/ARMeilleure/Optimizations.cs
index 986b0c9ec..73c150dc8 100644
--- a/ARMeilleure/Optimizations.cs
+++ b/ARMeilleure/Optimizations.cs
@@ -8,6 +8,7 @@ namespace ARMeilleure
 
         public static bool AllowLcqInFunctionTable  { get; set; } = true;
         public static bool UseUnmanagedDispatchLoop { get; set; } = true;
+        public static bool EnableDebugging          { get; set; } = false;
 
         public static bool UseSseIfAvailable       { get; set; } = true;
         public static bool UseSse2IfAvailable      { get; set; } = true;
diff --git a/ARMeilleure/Translation/ArmEmitterContext.cs b/ARMeilleure/Translation/ArmEmitterContext.cs
index 33355daec..e0ede2054 100644
--- a/ARMeilleure/Translation/ArmEmitterContext.cs
+++ b/ARMeilleure/Translation/ArmEmitterContext.cs
@@ -68,7 +68,7 @@ namespace ARMeilleure.Translation
             bool highCq,
             Aarch32Mode mode)
         {
-            HasPtc = Ptc.State != PtcState.Disabled;
+            HasPtc = Ptc.State != PtcState.Disabled && !Optimizations.EnableDebugging;
             Memory = memory;
             CountTable = countTable;
             FunctionTable = funcTable;
diff --git a/ARMeilleure/Translation/Translator.cs b/ARMeilleure/Translation/Translator.cs
index 389adf292..2ddebefa2 100644
--- a/ARMeilleure/Translation/Translator.cs
+++ b/ARMeilleure/Translation/Translator.cs
@@ -169,7 +169,33 @@ namespace ARMeilleure.Translation
 
             NativeInterface.RegisterThread(context, Memory, this);
 
-            if (Optimizations.UseUnmanagedDispatchLoop)
+            if (Optimizations.EnableDebugging)
+            {
+                context.DebugPc = address;
+                do
+                {
+                    context.DebugPc = ExecuteSingle(context, context.DebugPc);
+
+                    while (context._debugState != (int)DebugState.Running)
+                    {
+                        Interlocked.CompareExchange(ref context._debugState, (int)DebugState.Stopped, (int)DebugState.Stopping);
+                        context._debugHalt.WaitOne();
+                        if (Interlocked.CompareExchange(ref context._shouldStep, 0, 1) == 1)
+                        {
+                            context.DebugPc = Step(context, context.DebugPc);
+
+                            context._stepBarrier.SignalAndWait();
+                            context._stepBarrier.SignalAndWait();
+                        }
+                        else
+                        {
+                            Interlocked.CompareExchange(ref context._debugState, (int)DebugState.Running, (int)DebugState.Stopped);
+                        }
+                    }
+                }
+                while (context.Running && context.DebugPc != 0);
+            }
+            else if (Optimizations.UseUnmanagedDispatchLoop)
             {
                 Stubs.DispatchLoop(context.NativeContextPtr, address);
             }
@@ -368,9 +394,8 @@ namespace ARMeilleure.Translation
 
                 if (block.Exit)
                 {
-                    // Left option here as it may be useful if we need to return to managed rather than tail call in
-                    // future. (eg. for debug)
-                    bool useReturns = false;
+                    // Return to managed rather than tail call.
+                    bool useReturns = Optimizations.EnableDebugging;
 
                     InstEmitFlowHelper.EmitVirtualJump(context, Const(block.Address), isReturn: useReturns);
                 }