[hbelusca] 61356: [NTVDM] - Simplify EmulatorReadMemory (first MMIO-mapped devices copy their memory image back to the VM' memory area, then data is read via RtlCopyMemory), and EmulatorWriteMemory...

Author: hbelusca
Date: Mon Dec 23 18:09:18 2013
New Revision: 61356

URL: http://svn.reactos.org/svn/reactos?rev=61356&view=rev
Log:
[NTVDM]
- Simplify EmulatorReadMemory (first MMIO-mapped devices copy their memory image back to the VM' memory area, then data is read via RtlCopyMemory), and EmulatorWriteMemory (simplify VgaBuffer computation and rename this variable accordingly, for readability purposes).
- Fix Sim32pGetVDMPointer and MGetVdmPointer prototypes.

Modified:
    branches/ntvdm/subsystems/ntvdm/emulator.c

Modified: branches/ntvdm/subsystems/ntvdm/emulator.c
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/emulator....
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/emulator.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/emulator.c	[iso-8859-1] Mon Dec 23 18:09:18 2013
@@ -43,21 +43,24 @@
     /* Make sure the requested address is valid */
     if ((Address + Size) >= MAX_ADDRESS) return;

-    /* Read the data from the virtual address space and store it in the buffer */
-    RtlCopyMemory(Buffer, (LPVOID)((ULONG_PTR)BaseAddress + Address), Size);
-
-    /* Check if we modified the console video memory */
+    /*
+     * Check if we are going to read the VGA memory and
+     * copy it into the virtual address space if needed.
+     */
     if (((Address + Size) >= VgaGetVideoBaseAddress())
         && (Address < VgaGetVideoLimitAddress()))
     {
         DWORD VgaAddress = max(Address, VgaGetVideoBaseAddress());
         DWORD ActualSize = min(Address + Size - 1, VgaGetVideoLimitAddress())
                            - VgaAddress + 1;
-        LPBYTE VgaBuffer = (LPBYTE)((ULONG_PTR)Buffer + VgaAddress - Address);
+        LPBYTE DestBuffer = (LPBYTE)((ULONG_PTR)BaseAddress + VgaAddress);

/* Read from the VGA memory */
-        VgaReadMemory(VgaAddress, VgaBuffer, ActualSize);
+        VgaReadMemory(VgaAddress, DestBuffer, ActualSize);
     }
+
+    /* Read the data from the virtual address space and store it in the buffer */
+    RtlCopyMemory(Buffer, (LPVOID)((ULONG_PTR)BaseAddress + Address), Size);
 }

VOID WINAPI EmulatorWriteMemory(PFAST486_STATE State, ULONG Address, PVOID Buffer, ULONG Size)
@@ -76,17 +79,19 @@
     /* Read the data from the buffer and store it in the virtual address space */
     RtlCopyMemory((LPVOID)((ULONG_PTR)BaseAddress + Address), Buffer, Size);

-    /* Check if we modified the console video memory */
+    /*
+     * Check if we modified the VGA memory.
+     */
     if (((Address + Size) >= VgaGetVideoBaseAddress())
         && (Address < VgaGetVideoLimitAddress()))
     {
         DWORD VgaAddress = max(Address, VgaGetVideoBaseAddress());
         DWORD ActualSize = min(Address + Size - 1, VgaGetVideoLimitAddress())
                            - VgaAddress + 1;
-        LPBYTE VgaBuffer = (LPBYTE)((ULONG_PTR)Buffer + VgaAddress - Address);
+        LPBYTE SrcBuffer = (LPBYTE)((ULONG_PTR)BaseAddress + VgaAddress);

/* Write to the VGA memory */
-        VgaWriteMemory(VgaAddress, VgaBuffer, ActualSize);
+        VgaWriteMemory(VgaAddress, SrcBuffer, ActualSize);
     }
 }

@@ -178,8 +183,8 @@

PBYTE
 WINAPI
-Sim32pGetVDMPointer(IN ULONG Address,
-                    IN BOOL  ProtectedMode)
+Sim32pGetVDMPointer(IN ULONG   Address,
+                    IN BOOLEAN ProtectedMode)
 {
     // FIXME
     UNREFERENCED_PARAMETER(ProtectedMode);
@@ -189,14 +194,14 @@
      *                 or Selector (if ProtectedMode == TRUE )
      * LOWORD(Address) == Offset
      */
-    return SEG_OFF_TO_PTR(HIWORD(Address), LOWORD(Address));
+    return (PBYTE)FAR_POINTER(Address);
 }

PBYTE
 WINAPI
-MGetVdmPointer(IN ULONG Address,
-               IN ULONG Size,
-               IN BOOL ProtectedMode)
+MGetVdmPointer(IN ULONG   Address,
+               IN ULONG   Size,
+               IN BOOLEAN ProtectedMode)
 {
     UNREFERENCED_PARAMETER(Size);
     return Sim32pGetVDMPointer(Address, ProtectedMode);