From eafe47fee003c421e122089027a405dab41df81f Mon Sep 17 00:00:00 2001
From: gdkchan <gab.dark.100@gmail.com>
Date: Fri, 8 Jun 2018 21:15:56 -0300
Subject: [PATCH] Texture/Vertex/Index data cache (#132)

* Initial implementation of the texture cache

* Cache vertex and index data aswell, some cleanup

* Improve handling of the cache by storing cached ranges on a list for each page

* Delete old data from the caches automatically, ensure that the cache is cleaned when the mapping/size changes, and some general cleanup
---
 Memory/AMemory.cs      | 63 ++++++++++++++++++++++++++++++++++--
 Memory/AMemoryWin32.cs | 73 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+), 2 deletions(-)
 create mode 100644 Memory/AMemoryWin32.cs

diff --git a/Memory/AMemory.cs b/Memory/AMemory.cs
index e7d4656..7e9a358 100644
--- a/Memory/AMemory.cs
+++ b/Memory/AMemory.cs
@@ -54,7 +54,14 @@ namespace ChocolArm64.Memory
 
             ExAddrs = new HashSet<long>();
 
-            Ram = Marshal.AllocHGlobal((IntPtr)AMemoryMgr.RamSize + AMemoryMgr.PageSize);
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                Ram = AMemoryWin32.Allocate((IntPtr)AMemoryMgr.RamSize + AMemoryMgr.PageSize);
+            }
+            else
+            {
+                Ram = Marshal.AllocHGlobal((IntPtr)AMemoryMgr.RamSize + AMemoryMgr.PageSize);
+            }
 
             RamPtr = (byte*)Ram;
         }
@@ -141,6 +148,51 @@ namespace ChocolArm64.Memory
             }
         }
 
+        public long GetHostPageSize()
+        {
+            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return AMemoryMgr.PageSize;
+            }
+
+            IntPtr MemAddress = new IntPtr(RamPtr);
+            IntPtr MemSize    = new IntPtr(AMemoryMgr.RamSize);
+
+            long PageSize = AMemoryWin32.IsRegionModified(MemAddress, MemSize, Reset: false);
+
+            if (PageSize < 1)
+            {
+                throw new InvalidOperationException();
+            }
+
+            return PageSize;
+        }
+
+        public bool IsRegionModified(long Position, long Size)
+        {
+            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return true;
+            }
+
+            long EndPos = Position + Size;
+
+            if ((ulong)EndPos < (ulong)Position)
+            {
+                return false;
+            }
+
+            if ((ulong)EndPos > AMemoryMgr.RamSize)
+            {
+                return false;
+            }
+
+            IntPtr MemAddress = new IntPtr(RamPtr + Position);
+            IntPtr MemSize    = new IntPtr(Size);
+
+            return AMemoryWin32.IsRegionModified(MemAddress, MemSize, Reset: true) != 0;
+        }
+
         public sbyte ReadSByte(long Position)
         {
             return (sbyte)ReadByte(Position);
@@ -640,7 +692,14 @@ namespace ChocolArm64.Memory
         {
             if (Ram != IntPtr.Zero)
             {
-                Marshal.FreeHGlobal(Ram);
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                {
+                    AMemoryWin32.Free(Ram);
+                }
+                else
+                {
+                    Marshal.FreeHGlobal(Ram);
+                }
 
                 Ram = IntPtr.Zero;
             }
diff --git a/Memory/AMemoryWin32.cs b/Memory/AMemoryWin32.cs
new file mode 100644
index 0000000..d097dc8
--- /dev/null
+++ b/Memory/AMemoryWin32.cs
@@ -0,0 +1,73 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace ChocolArm64.Memory
+{
+    static class AMemoryWin32
+    {
+        private const int MEM_COMMIT      = 0x00001000;
+        private const int MEM_RESERVE     = 0x00002000;
+        private const int MEM_WRITE_WATCH = 0x00200000;
+
+        private const int PAGE_READWRITE = 0x04;
+
+        private const int MEM_RELEASE = 0x8000;
+
+        private const int WRITE_WATCH_FLAG_RESET = 1;
+
+        [DllImport("kernel32.dll")]
+        private static extern IntPtr VirtualAlloc(IntPtr lpAddress, IntPtr dwSize, int flAllocationType, int flProtect);
+
+        [DllImport("kernel32.dll")]
+        private static extern bool VirtualFree(IntPtr lpAddress, IntPtr dwSize, int dwFreeType);
+
+        [DllImport("kernel32.dll")]
+        private unsafe static extern int GetWriteWatch(
+            int      dwFlags,
+            IntPtr   lpBaseAddress,
+            IntPtr   dwRegionSize,
+            IntPtr[] lpAddresses,
+            long*    lpdwCount,
+            long*    lpdwGranularity);
+
+        public static IntPtr Allocate(IntPtr Size)
+        {
+            const int Flags = MEM_COMMIT | MEM_RESERVE | MEM_WRITE_WATCH;
+
+            IntPtr Address = VirtualAlloc(IntPtr.Zero, Size, Flags, PAGE_READWRITE);
+
+            if (Address == IntPtr.Zero)
+            {
+                throw new InvalidOperationException();
+            }
+
+            return Address;
+        }
+
+        public static void Free(IntPtr Address)
+        {
+            VirtualFree(Address, IntPtr.Zero, MEM_RELEASE);
+        }
+
+        public unsafe static long IsRegionModified(IntPtr Address, IntPtr Size, bool Reset)
+        {
+            IntPtr[] Addresses = new IntPtr[1];
+
+            long Count = Addresses.Length;
+
+            long Granularity;
+
+            int Flags = Reset ? WRITE_WATCH_FLAG_RESET : 0;
+
+            GetWriteWatch(
+                Flags,
+                Address,
+                Size,
+                Addresses,
+                &Count,
+                &Granularity);
+
+            return Count != 0 ? Granularity : 0;
+        }
+    }
+}
\ No newline at end of file