[aandrejevic] 61797: [NTVDM] Add two general-purpose variables to the interrupt handler stub stack. Fix INT 29h so that it works correctly when the INT 10h, AH = 0Eh call is hooked.

Author: aandrejevic
Date: Sat Jan 25 00:53:10 2014
New Revision: 61797

URL: http://svn.reactos.org/svn/reactos?rev=61797&view=rev
Log:
[NTVDM]
Add two general-purpose variables to the interrupt handler stub stack.
Fix INT 29h so that it works correctly when the INT 10h, AH = 0Eh call is hooked.

Modified:
    branches/ntvdm/subsystems/ntvdm/dos/dos.c
    branches/ntvdm/subsystems/ntvdm/emulator.h
    branches/ntvdm/subsystems/ntvdm/int32.c

Modified: branches/ntvdm/subsystems/ntvdm/dos/dos.c
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/dos/dos.c...
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/dos/dos.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/dos/dos.c	[iso-8859-1] Sat Jan 25 00:53:10 2014
@@ -2675,15 +2675,31 @@
      * See Ralf Brown: http://www.ctyme.com/intr/rb-4124.htm
      * for more information.
      */
-    UNREFERENCED_PARAMETER(Stack);
-
-    /*
-     * The default handler under DOS 2.x and 3.x simply calls INT 10/AH=0Eh.
-     * Do better and call directly VidBiosPrintCharacter: it's what INT 10/AH=0Eh
-     * does. Otherwise we would have to set BL to DOS_CHAR_ATTRIBUTE and
-     * BH to Bda->VideoPage.
-     */
-    VidBiosPrintCharacter(getAL(), DOS_CHAR_ATTRIBUTE, Bda->VideoPage);
+
+    if (Stack[STACK_COUNTER] == 0)
+    {
+        Stack[STACK_COUNTER]++;
+
+        /* Save AX and BX */
+        Stack[STACK_VAR_A] = getAX();
+        Stack[STACK_VAR_B] = getBX();
+
+        /* Rewind the BOP manually, we can't use CF because the interrupt could modify it */
+        EmulatorExecute(getCS(), getIP() - 4);
+
+        /* Call INT 0x10, AH = 0x0E */
+        setAH(0x0E);
+        setBL(DOS_CHAR_ATTRIBUTE);
+        setBH(Bda->VideoPage);
+
+        EmulatorInterrupt(0x10);
+    }
+    else
+    {
+        /* Restore AX and BX */
+        setAX(Stack[STACK_VAR_A]);
+        setBX(Stack[STACK_VAR_B]);
+    }
 }

VOID WINAPI DosInt2Fh(LPWORD Stack)

Modified: branches/ntvdm/subsystems/ntvdm/emulator.h
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/emulator....
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/emulator.h	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/emulator.h	[iso-8859-1] Sat Jan 25 00:53:10 2014
@@ -34,11 +34,13 @@
 #define EMULATOR_FLAG_VIP (1 << 20)
 #define EMULATOR_FLAG_ID (1 << 21)

-#define STACK_COUNTER   0
-#define STACK_INT_NUM   1
-#define STACK_IP        2
-#define STACK_CS        3
-#define STACK_FLAGS     4
+#define STACK_VAR_B     0
+#define STACK_VAR_A     1
+#define STACK_COUNTER   2
+#define STACK_INT_NUM   3
+#define STACK_IP        4
+#define STACK_CS        5
+#define STACK_FLAGS     6

/* Basic Memory Management */

Modified: branches/ntvdm/subsystems/ntvdm/int32.c
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/int32.c?r...
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/int32.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/int32.c	[iso-8859-1] Sat Jan 25 00:53:10 2014
@@ -74,8 +74,14 @@
         BiosCode[Offset++] = 0x6A; // push i
         BiosCode[Offset++] = (UCHAR)i;

+        /* The counter variable (initialized to 0) */
         BiosCode[Offset++] = 0x6A; // push 0
         BiosCode[Offset++] = 0x00;
+
+        /* Stack variables */
+        BiosCode[Offset++] = 0x83; // sub sp, 4
+        BiosCode[Offset++] = 0xEC;
+        BiosCode[Offset++] = 0x04;

BopSeqOffset = COMMON_STUB_OFFSET - (Offset + 3);

@@ -107,9 +113,9 @@
     BiosCode[Offset++] = 0xF5;

// EXIT:
-    BiosCode[Offset++] = 0x83; // add sp, 4
+    BiosCode[Offset++] = 0x83; // add sp, 8
     BiosCode[Offset++] = 0xC4;
-    BiosCode[Offset++] = 0x04;
+    BiosCode[Offset++] = 0x08;

BiosCode[Offset++] = 0xCF; // iret