Refactor CPU interface to allow the implementation of other CPU emulators (#3362)

* Refactor CPU interface

* Use IExecutionContext interface on SVC handler, change how CPU interrupts invokes the handlers

* Make CpuEngine take a ITickSource rather than returning one

The previous implementation had the scenario where the CPU engine had to implement the tick source in mind, like for example, when we have a hypervisor and the game can read CNTPCT on the host directly. However given that we need to do conversion due to different frequencies anyway, it's not worth it. It's better to just let the user pass the tick source and redirect any reads to CNTPCT to the user tick source

* XML docs for the public interfaces

* PPTC invalidation due to NativeInterface function name changes

* Fix build of the CPU tests

* PR feedback

10 files changed, 72 insertions, 95 deletions

diff --git a/ARMeilleure/Instructions/InstEmitSystem.cs b/ARMeilleure/Instructions/InstEmitSystem.cs
index 499f1648..50dab07d 100644
--- a/ARMeilleure/Instructions/InstEmitSystem.cs
+++ b/ARMeilleure/Instructions/InstEmitSystem.cs
@@ -33,13 +33,13 @@ namespace ARMeilleure.Instructions
 
             switch (GetPackedId(op))
             {
-                case 0b11_011_0000_0000_001: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetCtrEl0));    break;
-                case 0b11_011_0000_0000_111: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetDczidEl0));  break;
-                case 0b11_011_0100_0010_000: EmitGetNzcv(context);                                                           return;
-                case 0b11_011_0100_0100_000: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFpcr));      break;
-                case 0b11_011_0100_0100_001: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFpsr));      break;
-                case 0b11_011_1101_0000_010: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidrEl0));  break;
-                case 0b11_011_1101_0000_011: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidr));     break;
+                case 0b11_011_0000_0000_001: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetCtrEl0)); break;
+                case 0b11_011_0000_0000_111: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetDczidEl0)); break;
+                case 0b11_011_0100_0010_000: EmitGetNzcv(context); return;
+                case 0b11_011_0100_0100_000: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFpcr)); break;
+                case 0b11_011_0100_0100_001: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFpsr)); break;
+                case 0b11_011_1101_0000_010: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidrEl0)); break;
+                case 0b11_011_1101_0000_011: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidrroEl0)); break;
                 case 0b11_011_1110_0000_000: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetCntfrqEl0)); break;
                 case 0b11_011_1110_0000_001: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetCntpctEl0)); break;
                 case 0b11_011_1110_0000_010: info = typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetCntvctEl0)); break;
diff --git a/ARMeilleure/Instructions/NativeInterface.cs b/ARMeilleure/Instructions/NativeInterface.cs
index 0b76f681..eebb824e 100644
--- a/ARMeilleure/Instructions/NativeInterface.cs
+++ b/ARMeilleure/Instructions/NativeInterface.cs
@@ -107,14 +107,14 @@ namespace ARMeilleure.Instructions
             return (uint)GetContext().TpidrEl0;
         }
 
-        public static ulong GetTpidr()
+        public static ulong GetTpidrroEl0()
         {
-            return (ulong)GetContext().Tpidr;
+            return (ulong)GetContext().TpidrroEl0;
         }
 
         public static uint GetTpidr32()
         {
-            return (uint)GetContext().Tpidr;
+            return (uint)GetContext().TpidrroEl0;
         }
 
         public static ulong GetCntfrqEl0()
diff --git a/ARMeilleure/State/ExceptionCallback.cs b/ARMeilleure/State/ExceptionCallback.cs
new file mode 100644
index 00000000..38d6eef7
--- /dev/null
+++ b/ARMeilleure/State/ExceptionCallback.cs
@@ -0,0 +1,5 @@
+namespace ARMeilleure.State
+{
+    public delegate void ExceptionCallbackNoArgs(ExecutionContext context);
+    public delegate void ExceptionCallback(ExecutionContext context, ulong address, int id);
+}
\ No newline at end of file
diff --git a/ARMeilleure/State/ExecutionContext.cs b/ARMeilleure/State/ExecutionContext.cs
index 8309864f..c73ca197 100644
--- a/ARMeilleure/State/ExecutionContext.cs
+++ b/ARMeilleure/State/ExecutionContext.cs
@@ -1,6 +1,5 @@
 using ARMeilleure.Memory;
 using System;
-using System.Diagnostics;
 
 namespace ARMeilleure.State
 {
@@ -14,34 +13,22 @@ namespace ARMeilleure.State
 
         private bool _interrupted;
 
-        private static Stopwatch _tickCounter;
+        private readonly ICounter _counter;
 
-        private static double _hostTickFreq;
+        public ulong Pc => _nativeContext.GetPc();
 
-        public uint CtrEl0   => 0x8444c004;
+        public uint CtrEl0 => 0x8444c004;
         public uint DczidEl0 => 0x00000004;
 
-        public ulong CntfrqEl0 { get; set; }
-        public ulong CntpctEl0
-        {
-            get
-            {
-                double ticks = _tickCounter.ElapsedTicks * _hostTickFreq;
-
-                return (ulong)(ticks * CntfrqEl0);
-            }
-        }
+        public ulong CntfrqEl0 => _counter.Frequency;
+        public ulong CntpctEl0 => _counter.Counter;
 
         // CNTVCT_EL0 = CNTPCT_EL0 - CNTVOFF_EL2
         // Since EL2 isn't implemented, CNTVOFF_EL2 = 0
         public ulong CntvctEl0 => CntpctEl0;
 
-        public static TimeSpan ElapsedTime => _tickCounter.Elapsed;
-        public static long ElapsedTicks => _tickCounter.ElapsedTicks;
-        public static double TickFrequency => _hostTickFreq;
-
         public long TpidrEl0 { get; set; }
-        public long Tpidr    { get; set; }
+        public long TpidrroEl0 { get; set; }
 
         public uint Pstate
         {
@@ -78,35 +65,38 @@ namespace ARMeilleure.State
             private set => _nativeContext.SetRunning(value);
         }
 
-        public event EventHandler<EventArgs>              Interrupt;
-        public event EventHandler<InstExceptionEventArgs> Break;
-        public event EventHandler<InstExceptionEventArgs> SupervisorCall;
-        public event EventHandler<InstUndefinedEventArgs> Undefined;
-
-        static ExecutionContext()
-        {
-            _hostTickFreq = 1.0 / Stopwatch.Frequency;
-
-            _tickCounter = new Stopwatch();
-            _tickCounter.Start();
-        }
-
-        public ExecutionContext(IJitMemoryAllocator allocator)
+        private readonly ExceptionCallbackNoArgs _interruptCallback;
+        private readonly ExceptionCallback _breakCallback;
+        private readonly ExceptionCallback _supervisorCallback;
+        private readonly ExceptionCallback _undefinedCallback;
+
+        public ExecutionContext(
+            IJitMemoryAllocator allocator,
+            ICounter counter,
+            ExceptionCallbackNoArgs interruptCallback = null,
+            ExceptionCallback breakCallback = null,
+            ExceptionCallback supervisorCallback = null,
+            ExceptionCallback undefinedCallback = null)
         {
             _nativeContext = new NativeContext(allocator);
+            _counter = counter;
+            _interruptCallback = interruptCallback;
+            _breakCallback = breakCallback;
+            _supervisorCallback = supervisorCallback;
+            _undefinedCallback = undefinedCallback;
 
             Running = true;
 
             _nativeContext.SetCounter(MinCountForCheck);
         }
 
-        public ulong GetX(int index)              => _nativeContext.GetX(index);
-        public void  SetX(int index, ulong value) => _nativeContext.SetX(index, value);
+        public ulong GetX(int index) => _nativeContext.GetX(index);
+        public void SetX(int index, ulong value) => _nativeContext.SetX(index, value);
 
-        public V128 GetV(int index)             => _nativeContext.GetV(index);
+        public V128 GetV(int index) => _nativeContext.GetV(index);
         public void SetV(int index, V128 value) => _nativeContext.SetV(index, value);
 
-        public bool GetPstateFlag(PState flag)             => _nativeContext.GetPstateFlag(flag);
+        public bool GetPstateFlag(PState flag) => _nativeContext.GetPstateFlag(flag);
         public void SetPstateFlag(PState flag, bool value) => _nativeContext.SetPstateFlag(flag, value);
 
         public bool GetFPstateFlag(FPState flag) => _nativeContext.GetFPStateFlag(flag);
@@ -118,7 +108,7 @@ namespace ARMeilleure.State
             {
                 _interrupted = false;
 
-                Interrupt?.Invoke(this, EventArgs.Empty);
+                _interruptCallback?.Invoke(this);
             }
 
             _nativeContext.SetCounter(MinCountForCheck);
@@ -131,17 +121,17 @@ namespace ARMeilleure.State
 
         internal void OnBreak(ulong address, int imm)
         {
-            Break?.Invoke(this, new InstExceptionEventArgs(address, imm));
+            _breakCallback?.Invoke(this, address, imm);
         }
 
         internal void OnSupervisorCall(ulong address, int imm)
         {
-            SupervisorCall?.Invoke(this, new InstExceptionEventArgs(address, imm));
+            _supervisorCallback?.Invoke(this, address, imm);
         }
 
         internal void OnUndefined(ulong address, int opCode)
         {
-            Undefined?.Invoke(this, new InstUndefinedEventArgs(address, opCode));
+            _undefinedCallback?.Invoke(this, address, opCode);
         }
 
         public void StopRunning()
@@ -151,16 +141,6 @@ namespace ARMeilleure.State
             _nativeContext.SetCounter(0);
         }
 
-        public static void SuspendCounter()
-        {
-            _tickCounter.Stop();
-        }
-
-        public static void ResumeCounter()
-        {
-            _tickCounter.Start();
-        }
-
         public void Dispose()
         {
             _nativeContext.Dispose();
diff --git a/ARMeilleure/State/ICounter.cs b/ARMeilleure/State/ICounter.cs
new file mode 100644
index 00000000..93e721ea
--- /dev/null
+++ b/ARMeilleure/State/ICounter.cs
@@ -0,0 +1,18 @@
+namespace ARMeilleure.State
+{
+    /// <summary>
+    /// CPU Counter interface.
+    /// </summary>
+    public interface ICounter
+    {
+        /// <summary>
+        /// Counter frequency in Hertz.
+        /// </summary>
+        ulong Frequency { get; }
+
+        /// <summary>
+        /// Current counter value.
+        /// </summary>
+        ulong Counter { get; }
+    }
+}
\ No newline at end of file
diff --git a/ARMeilleure/State/InstExceptionEventArgs.cs b/ARMeilleure/State/InstExceptionEventArgs.cs
deleted file mode 100644
index c2460e4b..00000000
--- a/ARMeilleure/State/InstExceptionEventArgs.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-using System;
-
-namespace ARMeilleure.State
-{
-    public class InstExceptionEventArgs : EventArgs
-    {
-        public ulong Address { get; }
-        public int   Id      { get; }
-
-        public InstExceptionEventArgs(ulong address, int id)
-        {
-            Address = address;
-            Id      = id;
-        }
-    }
-}
\ No newline at end of file
diff --git a/ARMeilleure/State/InstUndefinedEventArgs.cs b/ARMeilleure/State/InstUndefinedEventArgs.cs
deleted file mode 100644
index c02b648e..00000000
--- a/ARMeilleure/State/InstUndefinedEventArgs.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-using System;
-
-namespace ARMeilleure.State
-{
-    public class InstUndefinedEventArgs : EventArgs
-    {
-        public ulong Address { get; }
-        public int   OpCode  { get; }
-
-        public InstUndefinedEventArgs(ulong address, int opCode)
-        {
-            Address = address;
-            OpCode  = opCode;
-        }
-    }
-}
\ No newline at end of file
diff --git a/ARMeilleure/State/NativeContext.cs b/ARMeilleure/State/NativeContext.cs
index f911f762..11ab5ca3 100644
--- a/ARMeilleure/State/NativeContext.cs
+++ b/ARMeilleure/State/NativeContext.cs
@@ -34,6 +34,12 @@ namespace ARMeilleure.State
             GetStorage().ExclusiveAddress = ulong.MaxValue;
         }
 
+        public ulong GetPc()
+        {
+            // TODO: More precise tracking of PC value.
+            return GetStorage().DispatchAddress;
+        }
+
         public unsafe ulong GetX(int index)
         {
             if ((uint)index >= RegisterConsts.IntRegsCount)
diff --git a/ARMeilleure/Translation/Delegates.cs b/ARMeilleure/Translation/Delegates.cs
index 3cfe34b6..6d40dc96 100644
--- a/ARMeilleure/Translation/Delegates.cs
+++ b/ARMeilleure/Translation/Delegates.cs
@@ -115,7 +115,7 @@ namespace ARMeilleure.Translation
             SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFpsr)));
             SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetFunctionAddress)));
             SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.InvalidateCacheLine)));
-            SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidr)));
+            SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidrroEl0)));
             SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidr32))); // A32 only.
             SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidrEl0)));
             SetDelegateInfo(typeof(NativeInterface).GetMethod(nameof(NativeInterface.GetTpidrEl032))); // A32 only.
diff --git a/ARMeilleure/Translation/PTC/Ptc.cs b/ARMeilleure/Translation/PTC/Ptc.cs
index 43f3b08b..9671a871 100644
--- a/ARMeilleure/Translation/PTC/Ptc.cs
+++ b/ARMeilleure/Translation/PTC/Ptc.cs
@@ -27,7 +27,7 @@ namespace ARMeilleure.Translation.PTC
         private const string OuterHeaderMagicString = "PTCohd\0\0";
         private const string InnerHeaderMagicString = "PTCihd\0\0";
 
-        private const uint InternalVersion = 3267; //! To be incremented manually for each change to the ARMeilleure project.
+        private const uint InternalVersion = 3362; //! To be incremented manually for each change to the ARMeilleure project.
 
         private const string ActualDir = "0";
         private const string BackupDir = "1";