FS: Structure emulation.

Cxbx.dsp

@@ -71,7 +71,7 @@ PostBuild_Cmds=cd PostBuild	upxCxbx.bat
 # PROP Intermediate_Dir "Bin\Debug"
 # PROP Target_Dir ""
 # ADD BASE CPP /nologo /W3 /Gm /GX /ZI /Od /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /D "_MBCS" /YX /FD /GZ /c
-# ADD CPP /nologo /MTd /W3 /Gm /GX /ZI /Od /I "Include" /I "Include/Win32/" /I "Include/Win32/Cxbxkrnl" /I "Include/Win32/Cxbx" /I "Resource" /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /D "_MBCS" /YX /FD /GZ /c
+# ADD CPP /nologo /MTd /W3 /Gm /GX /ZI /Od /I "Include" /I "Include/Win32/" /I "Include/Win32/Cxbxkrnl" /I "Include/Win32/Cxbx" /I "Resource" /D "WIN32" /D "_DEBUG" /D "_WINDOWS" /D "_MBCS" /FR /YX /FD /GZ /c
 # ADD BASE MTL /nologo /D "_DEBUG" /mktyplib203 /win32
 # ADD MTL /nologo /D "_DEBUG" /mktyplib203 /win32
 # ADD BASE RSC /l 0x409 /d "_DEBUG"
@@ -118,6 +118,10 @@ SOURCE=.\Include\Cxbx.h
 # End Source File
 # Begin Source File
 
+SOURCE=.\Include\Win32\CxbxKrnl\CxbxKrnl.h
+# End Source File
+# Begin Source File
+
 SOURCE=.\Include\Win32\Cxbx\EmuExe.h
 # End Source File
 # Begin Source File
@@ -130,10 +134,6 @@ SOURCE=.\Include\Core\Exe.h
 # End Source File
 # Begin Source File
 
-SOURCE=.\Include\Win32\CxbxKrnl\CxbxKrnl.h
-# End Source File
-# Begin Source File
-
 SOURCE=.\Include\Win32\Cxbx\Prolog.h
 # End Source File
 # Begin Source File

Doc/Todo.txt

@@ -2,7 +2,10 @@ Cxbx Todo:
 
   General Code Cleanup [caustik]
 
-  FS: structure construction (EmuXInit)
+  - FS: structure construction (EmuXInit)
+
+      - Initialize necessary components of EmuXFS
+      - SwapFS before *all* Win32/NT calls.
 
   Debug outputs should be configurable to STDOUT (console) or text file.
 

Source/Win32/CxbxKrnl/CxbxKrnl.cpp

@@ -60,6 +60,25 @@ namespace win32
 
 using namespace win32;
 
+// ******************************************************************
+// * func: EmuXSwapFS
+// ******************************************************************
+// *
+// * This function is used to swap between the native Win2k/XP FS:
+// * structure, and the EmuX FS: structure. Before running Windows
+// * code, you *must* swap over to Win2k/XP FS. Similarly, before
+// * running Xbox code, you *must* swap back over to EmuX FS.
+// *
+// ******************************************************************
+inline void EmuXSwapFS()
+{
+    __asm
+    {
+        mov ax, fs:[0x14]
+        mov fs, ax
+    }
+}
+
 // ******************************************************************
 // * func: EmuXGenerateFS
 // ******************************************************************
@@ -74,7 +93,7 @@ void EmuXGenerateFS()
     uint16 NewFS = LDTAllocate(pNewFS, pNewFS + dwSize);
 
     // ******************************************************************
-    // * Save the "old" FS  : [OrgFS = FS]
+    // * Obtain "OrgFS"
     // ******************************************************************
     __asm
     {
@@ -83,15 +102,26 @@ void EmuXGenerateFS()
     }
 
     // ******************************************************************
-    // * Update "new" FS    : [FS = NewFS, FS:[0x025C] = OrgFS]
+    // * Save "NewFS" inside OrgFS.ArbitraryUserPointer
     // ******************************************************************
     __asm
     {
         mov ax, NewFS
-        mov fs, ax
+        mov fs:[0x14], ax
+    }
 
+    // ******************************************************************
+    // * Swap into the "NewFS"
+    // ******************************************************************
+    EmuXSwapFS();
+
+    // ******************************************************************
+    // * Save "OrgFS" inside NewFS.ArbitraryUserPointer
+    // ******************************************************************
+    __asm
+    {
         mov ax, OrgFS
-        mov fs:[0x025C], ax
+        mov fs:[0x14], ax
     }
 }
 
@@ -156,24 +186,17 @@ CXBXKRNL_API void NTAPI EmuXInit(uint32 DebugConsole, uint08 *XBEHeader, uint32
     {
         EmuXGenerateFS();
 
-        // ******************************************************************
+        EmuXSwapFS();
-        // * Restore "old" FS   : [FS = FS:[0x025C]]
-        // ******************************************************************
-        __asm
-        {
-            mov     ax, fs:[0x025C]
-            mov     fs, ax
-        }
 
         NT_TIB *dbgTIB = 0;
 
+        // TODO: Store EmuX FS structure within the user data offset of Win2k/XP FS: struct
         __asm
         {
             mov esi, fs:[18h]
             mov dbgTIB, esi
         }
 
-        // TODO: Allocate new FS: within LDT, copy OriginalTIB to KPCR.NtTib, load new FS
         printf("CxbxKrnl [0x%.08X]: NT_TIB.Self=0x%.08X\n", GetCurrentThreadId(), dbgTIB->Self);
     }
 

Source/Win32/CxbxKrnl/LDT.cpp

@@ -76,8 +76,6 @@ void LDTSystemInit()
 // ******************************************************************
 uint16 LDTAllocate(uint32 dwBaseAddr, uint32 dwLimit)
 {
-    ULONG_PTR uBase = (ULONG_PTR)dwBaseAddr;
-
     xntdll::LDT_ENTRY LDTEntry;
 
     int x=0;
@@ -107,9 +105,9 @@ uint16 LDTAllocate(uint32 dwBaseAddr, uint32 dwLimit)
     // * Set up selector information
     // ******************************************************************
     {
-        LDTEntry.BaseLow                    = (WORD)(uBase & 0xFFFF);
+        LDTEntry.BaseLow                    = (WORD)(dwBaseAddr & 0xFFFF);
-        LDTEntry.HighWord.Bits.BaseMid      = (uBase >> 16) & 0xFF;
+        LDTEntry.HighWord.Bits.BaseMid      = (dwBaseAddr >> 16) & 0xFF;
-        LDTEntry.HighWord.Bits.BaseHi       = (uBase >> 24) & 0xFF;
+        LDTEntry.HighWord.Bits.BaseHi       = (dwBaseAddr >> 24) & 0xFF;
 	    LDTEntry.HighWord.Bits.Type         = 0x13; // RW data segment
 	    LDTEntry.HighWord.Bits.Dpl          = 3;    // user segment
 	    LDTEntry.HighWord.Bits.Pres         = 1;    // present