[fireball] 48745: [NTOS] - Daniel Zimmermann: Fix POPF bugs in VDM mode, namely truncation of the stackpointer to 16 bit and setting proper flags in the trapframe eflags register. This fixes proble...

Author: fireball
Date: Sat Sep 11 09:20:26 2010
New Revision: 48745

URL: http://svn.reactos.org/svn/reactos?rev=48745&view=rev
Log:
[NTOS]
- Daniel Zimmermann: Fix POPF bugs in VDM mode, namely truncation of the stackpointer to 16 bit and setting proper flags in the trapframe eflags register. This fixes problems with videocards calling int 0x10 VESA BIOS extension.
See issue #5608 for more details.

Modified:
    trunk/reactos/ntoskrnl/ke/i386/v86vdm.c

Modified: trunk/reactos/ntoskrnl/ke/i386/v86vdm.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/v86vdm.c?r...
==============================================================================
--- trunk/reactos/ntoskrnl/ke/i386/v86vdm.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/ke/i386/v86vdm.c [iso-8859-1] Sat Sep 11 09:20:26 2010
@@ -70,17 +70,17 @@

/* Build flat ESP */
     Esp = (TrapFrame->HardwareSegSs << 4) + (USHORT)TrapFrame->HardwareEsp;
-    Esp -= 2;

/* Check for OPER32 */
     if (KiVdmGetPrefixFlags(Flags) & PFX_FLAG_OPER32)
     {
         /* Save EFlags */
+        Esp -= 4;
+        *(PULONG)(Esp - 2) = V86EFlags;
+    }
+    else
+    {
         Esp -= 2;
-        *(PULONG)(Esp - 2) = V86EFlags;
-    }
-    else
-    {
         /* Save EFLags */
         *(PUSHORT)Esp = (USHORT)V86EFlags;
     }
@@ -103,20 +103,24 @@
     /* Build flat ESP */
     Esp = (TrapFrame->HardwareSegSs << 4) + (USHORT)TrapFrame->HardwareEsp;

-    /* Read EFlags */
-    EFlags = *(PULONG)Esp;
-    Esp += 4;
-    
     /* Check for OPER32 */
-    if (!(KiVdmGetPrefixFlags(Flags) & PFX_FLAG_OPER32))
-    {
+    if (KiVdmGetPrefixFlags(Flags) & PFX_FLAG_OPER32)
+    {
+        /* Read EFlags */
+        EFlags = *(PULONG)Esp;
+        Esp += 4;
+    }
+    else
+    {
+        /* Read EFlags */
+        EFlags = *(PUSHORT)Esp;
+        Esp += 2;
         /* Read correct flags and use correct stack address */
-        Esp -= 2;
         EFlags &= 0xFFFF;
     }

/* Set new ESP */
-    TrapFrame->HardwareEsp = Esp;
+    TrapFrame->HardwareEsp = (USHORT)Esp;

/* Mask out IOPL from the flags */
     EFlags &= ~EFLAGS_IOPL;
@@ -137,7 +141,7 @@
     V86EFlags |= EFLAGS_V86_MASK | EFLAGS_INTERRUPT_MASK;

/* Update EFlags in trap frame */
-    TrapFrame->EFlags |= V86EFlags;
+    TrapFrame->EFlags = V86EFlags;

/* Check if ESP0 needs to be fixed up */
     if (TrapEFlags & EFLAGS_V86_MASK) Ki386AdjustEsp0(TrapFrame);
@@ -311,6 +315,7 @@
     else
     {
         /* FIXME: Check for VDM interrupts */
+       DPRINT("FIXME: Check for VDM interrupts\n");
     }

/* We're done */