[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.

svn path=/trunk/; revision=48745

diff --git a/reactos/ntoskrnl/ke/i386/v86vdm.c b/reactos/ntoskrnl/ke/i386/v86vdm.c
index 4903d3e..bcb4b16 100644 (file)
--- a/reactos/ntoskrnl/ke/i386/v86vdm.c
+++ b/reactos/ntoskrnl/ke/i386/v86vdm.c
@@ -70,17 +70,17 @@ KiVdmOpcodePUSHF(IN PKTRAP_FRAME TrapFrame,
     
     /* Build flat ESP */
     Esp = (TrapFrame->HardwareSegSs << 4) + (USHORT)TrapFrame->HardwareEsp;
-    Esp -= 2;
     
     /* Check for OPER32 */
     if (KiVdmGetPrefixFlags(Flags) & PFX_FLAG_OPER32)
     {
         /* Save EFlags */
-        Esp -= 2;
+        Esp -= 4;
         *(PULONG)(Esp - 2) = V86EFlags;
     }
     else
     {
+        Esp -= 2;
         /* Save EFLags */
         *(PUSHORT)Esp = (USHORT)V86EFlags;
     }
@@ -103,20 +103,24 @@ KiVdmOpcodePOPF(IN PKTRAP_FRAME TrapFrame,
     /* 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 @@ KiVdmOpcodePOPF(IN PKTRAP_FRAME TrapFrame,
     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 @@ KiVdmOpcodeIRET(IN PKTRAP_FRAME TrapFrame,
     else
     {
         /* FIXME: Check for VDM interrupts */
+       DPRINT("FIXME: Check for VDM interrupts\n");
     }
     
     /* We're done */