Separate GPU engines (part 2/2) (#2440)

* 3D engine now uses DeviceState too, plus new state modification tracking

* Remove old methods code

* Remove GpuState and friends

* Optimize DeviceState, force inline some functions

* This change was not supposed to go in

* Proper channel initialization

* Optimize state read/write methods even more

* Fix debug build

* Do not dirty state if the write is redundant

* The YControl register should dirty either the viewport or front face state too, to update the host origin

* Avoid redundant vertex buffer updates

* Move state and get rid of the Ryujinx.Graphics.Gpu.State namespace

* Comments and nits

* Fix rebase

* PR feedback

* Move changed = false to improve codegen

* PR feedback

* Carry RyuJIT a bit more

4 files changed, 73 insertions, 78 deletions

diff --git a/Ryujinx.Graphics.Device/AccessControl.cs b/Ryujinx.Graphics.Device/AccessControl.cs
deleted file mode 100644
index 02203783..00000000
--- a/Ryujinx.Graphics.Device/AccessControl.cs
+++ /dev/null
@@ -1,10 +0,0 @@
-namespace Ryujinx.Graphics.Device
-{
-    public enum AccessControl
-    {
-        None      = 0,
-        ReadOnly  = 1 << 0,
-        WriteOnly = 1 << 1,
-        ReadWrite = ReadOnly | WriteOnly
-    }
-}
diff --git a/Ryujinx.Graphics.Device/DeviceState.cs b/Ryujinx.Graphics.Device/DeviceState.cs
index 1001d295..18100571 100644
--- a/Ryujinx.Graphics.Device/DeviceState.cs
+++ b/Ryujinx.Graphics.Device/DeviceState.cs
@@ -1,10 +1,8 @@
 using System;
-using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
-using System.Reflection;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace Ryujinx.Graphics.Device
 {
@@ -14,28 +12,22 @@ namespace Ryujinx.Graphics.Device
 
         public TState State;
 
-        private readonly BitArray _readableRegisters;
-        private readonly BitArray _writableRegisters;
+        private uint Size => (uint)(Unsafe.SizeOf<TState>() + RegisterSize - 1) / RegisterSize;
 
-        private readonly Dictionary<int, Func<int>> _readCallbacks;
-        private readonly Dictionary<int, Action<int>> _writeCallbacks;
+        private readonly Func<int>[] _readCallbacks;
+        private readonly Action<int>[] _writeCallbacks;
 
-        private readonly Dictionary<int, string> _fieldNamesForDebug;
+        private readonly Dictionary<uint, string> _fieldNamesForDebug;
         private readonly Action<string> _debugLogCallback;
 
         public DeviceState(IReadOnlyDictionary<string, RwCallback> callbacks = null, Action<string> debugLogCallback = null)
         {
-            int size = (Unsafe.SizeOf<TState>() + RegisterSize - 1) / RegisterSize;
-
-            _readableRegisters = new BitArray(size);
-            _writableRegisters = new BitArray(size);
-
-            _readCallbacks = new Dictionary<int, Func<int>>();
-            _writeCallbacks = new Dictionary<int, Action<int>>();
+            _readCallbacks = new Func<int>[Size];
+            _writeCallbacks = new Action<int>[Size];
 
             if (debugLogCallback != null)
             {
-                _fieldNamesForDebug = new Dictionary<int, string>();
+                _fieldNamesForDebug = new Dictionary<uint, string>();
                 _debugLogCallback = debugLogCallback;
             }
 
@@ -45,32 +37,30 @@ namespace Ryujinx.Graphics.Device
             for (int fieldIndex = 0; fieldIndex < fields.Length; fieldIndex++)
             {
                 var field = fields[fieldIndex];
-                var regAttr = field.GetCustomAttributes<RegisterAttribute>(false).FirstOrDefault();
 
                 int sizeOfField = SizeCalculator.SizeOf(field.FieldType);
 
                 for (int i = 0; i < ((sizeOfField + 3) & ~3); i += 4)
                 {
-                    _readableRegisters[(offset + i) / RegisterSize] = regAttr?.AccessControl.HasFlag(AccessControl.ReadOnly)  ?? true;
-                    _writableRegisters[(offset + i) / RegisterSize] = regAttr?.AccessControl.HasFlag(AccessControl.WriteOnly) ?? true;
-                }
-
-                if (callbacks != null && callbacks.TryGetValue(field.Name, out var cb))
-                {
-                    if (cb.Read != null)
-                    {
-                        _readCallbacks.Add(offset, cb.Read);
-                    }
+                    int index = (offset + i) / RegisterSize;
 
-                    if (cb.Write != null)
+                    if (callbacks != null && callbacks.TryGetValue(field.Name, out var cb))
                     {
-                        _writeCallbacks.Add(offset, cb.Write);
+                        if (cb.Read != null)
+                        {
+                            _readCallbacks[index] = cb.Read;
+                        }
+
+                        if (cb.Write != null)
+                        {
+                            _writeCallbacks[index] = cb.Write;
+                        }
                     }
                 }
 
                 if (debugLogCallback != null)
                 {
-                    _fieldNamesForDebug.Add(offset, field.Name);
+                    _fieldNamesForDebug.Add((uint)offset, field.Name);
                 }
 
                 offset += sizeOfField;
@@ -79,48 +69,71 @@ namespace Ryujinx.Graphics.Device
             Debug.Assert(offset == Unsafe.SizeOf<TState>());
         }
 
-        public virtual int Read(int offset)
+        public int Read(int offset)
         {
-            if (Check(offset) && _readableRegisters[offset / RegisterSize])
+            uint index = (uint)offset / RegisterSize;
+
+            if (index < Size)
             {
-                int alignedOffset = Align(offset);
+                uint alignedOffset = index * RegisterSize;
 
-                if (_readCallbacks.TryGetValue(alignedOffset, out Func<int> read))
+                var readCallback = Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(_readCallbacks), (IntPtr)index);
+                if (readCallback != null)
                 {
-                    return read();
+                    return readCallback();
                 }
                 else
                 {
-                    return GetRef<int>(alignedOffset);
+                    return GetRefUnchecked<int>(alignedOffset);
                 }
             }
 
             return 0;
         }
 
-        public virtual void Write(int offset, int data)
+        public void Write(int offset, int data)
         {
-            if (Check(offset) && _writableRegisters[offset / RegisterSize])
+            uint index = (uint)offset / RegisterSize;
+
+            if (index < Size)
             {
-                int alignedOffset = Align(offset);
+                uint alignedOffset = index * RegisterSize;
+                DebugWrite(alignedOffset, data);
 
-                if (_fieldNamesForDebug != null && _fieldNamesForDebug.TryGetValue(alignedOffset, out string fieldName))
-                {
-                    _debugLogCallback($"{typeof(TState).Name}.{fieldName} = 0x{data:X}");
-                }
+                GetRefIntAlignedUncheck(index) = data;
 
-                GetRef<int>(alignedOffset) = data;
+                Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(_writeCallbacks), (IntPtr)index)?.Invoke(data);
+            }
+        }
 
-                if (_writeCallbacks.TryGetValue(alignedOffset, out Action<int> write))
-                {
-                    write(data);
-                }
+        public void WriteWithRedundancyCheck(int offset, int data, out bool changed)
+        {
+            uint index = (uint)offset / RegisterSize;
+
+            if (index < Size)
+            {
+                uint alignedOffset = index * RegisterSize;
+                DebugWrite(alignedOffset, data);
+
+                ref var storage = ref GetRefIntAlignedUncheck(index);
+                changed = storage != data;
+                storage = data;
+
+                Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(_writeCallbacks), (IntPtr)index)?.Invoke(data);
+            }
+            else
+            {
+                changed = false;
             }
         }
 
-        private bool Check(int offset)
+        [Conditional("DEBUG")]
+        private void DebugWrite(uint alignedOffset, int data)
         {
-            return (uint)Align(offset) < Unsafe.SizeOf<TState>();
+            if (_fieldNamesForDebug != null && _fieldNamesForDebug.TryGetValue(alignedOffset, out string fieldName))
+            {
+                _debugLogCallback($"{typeof(TState).Name}.{fieldName} = 0x{data:X}");
+            }
         }
 
         public ref T GetRef<T>(int offset) where T : unmanaged
@@ -130,12 +143,19 @@ namespace Ryujinx.Graphics.Device
                 throw new ArgumentOutOfRangeException(nameof(offset));
             }
 
+            return ref GetRefUnchecked<T>((uint)offset);
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private ref T GetRefUnchecked<T>(uint offset) where T : unmanaged
+        {
             return ref Unsafe.As<TState, T>(ref Unsafe.AddByteOffset(ref State, (IntPtr)offset));
         }
 
-        private static int Align(int offset)
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private ref int GetRefIntAlignedUncheck(ulong index)
         {
-            return offset & ~(RegisterSize - 1);
+            return ref Unsafe.Add(ref Unsafe.As<TState, int>(ref State), (IntPtr)index);
         }
     }
 }
diff --git a/Ryujinx.Graphics.Device/RegisterAttribute.cs b/Ryujinx.Graphics.Device/RegisterAttribute.cs
deleted file mode 100644
index 6e198963..00000000
--- a/Ryujinx.Graphics.Device/RegisterAttribute.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using System;
-
-namespace Ryujinx.Graphics.Device
-{
-    [AttributeUsage(AttributeTargets.Field, AllowMultiple = false)]
-    public sealed class RegisterAttribute : Attribute
-    {
-        public AccessControl AccessControl { get; }
-
-        public RegisterAttribute(AccessControl ac)
-        {
-            AccessControl = ac;
-        }
-    }
-}
diff --git a/Ryujinx.Graphics.Device/SizeCalculator.cs b/Ryujinx.Graphics.Device/SizeCalculator.cs
index 7cc48915..7409c041 100644
--- a/Ryujinx.Graphics.Device/SizeCalculator.cs
+++ b/Ryujinx.Graphics.Device/SizeCalculator.cs
@@ -3,7 +3,7 @@ using System.Reflection;
 
 namespace Ryujinx.Graphics.Device
 {
-    static class SizeCalculator
+    public static class SizeCalculator
     {
         public static int SizeOf(Type type)
         {