[hbelusca] 68826: [NTVDM] Introduce a function for doing guest-to-guest memory copies (given here in a temporary implementation until a proper one is developed). It will be used in my next commit.

Author: hbelusca
Date: Wed Aug 26 00:37:50 2015
New Revision: 68826

URL: http://svn.reactos.org/svn/reactos?rev=68826&view=rev
Log:
[NTVDM]
Introduce a function for doing guest-to-guest memory copies (given here in a temporary implementation until a proper one is developed). It will be used in my next commit.

Modified:
    trunk/reactos/subsystems/mvdm/ntvdm/memory.c
    trunk/reactos/subsystems/mvdm/ntvdm/memory.h

Modified: trunk/reactos/subsystems/mvdm/ntvdm/memory.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/subsystems/mvdm/ntvdm/memor...
==============================================================================
--- trunk/reactos/subsystems/mvdm/ntvdm/memory.c	[iso-8859-1] (original)
+++ trunk/reactos/subsystems/mvdm/ntvdm/memory.c	[iso-8859-1] Wed Aug 26 00:37:50 2015
@@ -109,9 +109,7 @@
 #endif
 }

-static
-inline
-VOID
+static inline VOID
 ReadPage(PMEM_HOOK Hook, ULONG Address, PVOID Buffer, ULONG Size)
 {
     if (Hook && !Hook->hVdd && Hook->FastReadHandler)
@@ -122,9 +120,7 @@
     MemFastMoveMemory(Buffer, REAL_TO_PHYS(Address), Size);
 }

-static
-inline
-VOID
+static inline VOID
 WritePage(PMEM_HOOK Hook, ULONG Address, PVOID Buffer, ULONG Size)
 {
     if (!Hook
@@ -213,6 +209,62 @@
             Buffer = (PVOID)((ULONG_PTR)Buffer + Length);
         }
     }
+}
+
+VOID FASTCALL EmulatorCopyMemory(PFAST486_STATE State, ULONG DestAddress, ULONG SrcAddress, ULONG Size)
+{
+    /*
+     * Guest-to-guest memory copy
+     */
+
+    // FIXME: This is a temporary implementation of a more useful functionality
+    // which should be a merge of EmulatorReadMemory & EmulatorWriteMemory without
+    // any local external buffer.
+    // NOTE: Process heap is by default serialized (unless one specifies it shouldn't).
+    static BYTE StaticBuffer[8192]; // Smallest static buffer we can use.
+    static PVOID HeapBuffer = NULL; // Always-growing heap buffer. Use it in case StaticBuffer is too small.
+    static ULONG HeapBufferSize = 0;
+    PVOID LocalBuffer;              // Points to either StaticBuffer or HeapBuffer
+
+    if (Size <= sizeof(StaticBuffer))
+    {
+        /* Use the static buffer */
+        LocalBuffer = StaticBuffer;
+    }
+    else if (/* sizeof(StaticBuffer) <= Size && */ Size <= HeapBufferSize)
+    {
+        /* Use the heap buffer */
+        ASSERT(HeapBufferSize > 0 && HeapBuffer != NULL);
+        LocalBuffer = HeapBuffer;
+    }
+    else // if (Size > HeapBufferSize)
+    {
+        /* Enlarge the heap buffer and use it */
+
+        if (HeapBuffer == NULL)
+        {
+            /* First allocation */
+            LocalBuffer = RtlAllocateHeap(RtlGetProcessHeap(), 0, Size);
+        }
+        else
+        {
+            /* Reallocation */
+            LocalBuffer = RtlReAllocateHeap(RtlGetProcessHeap(), 0 /* HEAP_GENERATE_EXCEPTIONS */, HeapBuffer, Size);
+        }
+        ASSERT(LocalBuffer != NULL); // We must succeed! TODO: Handle it more properly.
+        HeapBuffer = LocalBuffer;    // HeapBuffer is now reallocated.
+        HeapBufferSize = Size;
+    }
+
+    /* Perform memory copy */
+    EmulatorReadMemory( State, SrcAddress , LocalBuffer, Size);
+    EmulatorWriteMemory(State, DestAddress, LocalBuffer, Size);
+
+    // if (LocalBuffer != StaticBuffer)
+    //     RtlFreeHeap(RtlGetProcessHeap(), 0, LocalBuffer);
+
+    // Note that we don't free HeapBuffer since it's an always-growing buffer.
+    // It is freed when NTVDM termiantes.
 }

VOID EmulatorSetA20(BOOLEAN Enabled)

Modified: trunk/reactos/subsystems/mvdm/ntvdm/memory.h
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/subsystems/mvdm/ntvdm/memor...
==============================================================================
--- trunk/reactos/subsystems/mvdm/ntvdm/memory.h	[iso-8859-1] (original)
+++ trunk/reactos/subsystems/mvdm/ntvdm/memory.h	[iso-8859-1] Wed Aug 26 00:37:50 2015
@@ -55,6 +55,16 @@
     ULONG Size
 );

+VOID
+FASTCALL
+EmulatorCopyMemory
+(
+    PFAST486_STATE State,
+    ULONG DestAddress,
+    ULONG SrcAddress,
+    ULONG Size
+);
+
 VOID EmulatorSetA20(BOOLEAN Enabled);
 BOOLEAN EmulatorGetA20(VOID);