[hbelusca] 67549: [NTVDM]: Add a debug feature to detect which apps erroneously call by themselves the BIOS initialization routine (POST). For whatever reason it is what MSD version 2 and above does.

Author: hbelusca
Date: Tue May  5 00:11:43 2015
New Revision: 67549

URL: http://svn.reactos.org/svn/reactos?rev=67549&view=rev
Log:
[NTVDM]: Add a debug feature to detect which apps erroneously call by themselves the BIOS
initialization routine (POST). For whatever reason it is what MSD version 2 and above
does.

Modified:
    trunk/reactos/subsystems/mvdm/ntvdm/bios/bios32/bios32.c

Modified: trunk/reactos/subsystems/mvdm/ntvdm/bios/bios32/bios32.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/subsystems/mvdm/ntvdm/bios…
==============================================================================
--- trunk/reactos/subsystems/mvdm/ntvdm/bios/bios32/bios32.c	[iso-8859-1] (original)
+++ trunk/reactos/subsystems/mvdm/ntvdm/bios/bios32/bios32.c	[iso-8859-1] Tue May  5
00:11:43 2015
@@ -619,6 +619,30 @@
     /* Set data segment */
     setDS(BDA_SEGMENT);
 
+    /*
+     * Check the word at 0040h:0072h (Bda->SoftReset) and do one of the
+     * following actions:
+     * - if the word is 0000h, perform a cold reboot (aka. Reset). Everything gets
initialized.
+     * - if the word is 1234h, perform a warm reboot (aka. Ctrl-Alt-Del). Some stuff is
skipped.
+     * In case we do a warm reboot, we need to check for the CMOS shutdown flag
+     * and take a suitable action.
+     */
+
+    // FIXME: This is a debug temporary check:
+    // Since NTVDM memory is by default initialized with 0xCC, it is also
+    // the case for the BDA. So at first boot we get SoftReset == 0xCCCC.
+    // After we zero out the BDA and put valid values in it.
+    // If for some reason an app calls the BIOS initialization code,
+    // SoftReset is normally zero (unless the app puts a non-null value in SoftReset)
+    // and we can detect that. With the current state of NTVDM, apps calling
+    // by hand the BIOS init code is a sign of a bug, e.g. see MSD.EXE version 2+.
+    if (Bda->SoftReset != 0xCCCC)
+    {
+        DisplayMessage(L"NTVDM is performing a COLD reboot! The program you are
currently testing seems to not behave correctly! The VDM is stopping...");
+        EmulatorTerminate();
+        return;
+    }
+
     /* Initialize the BDA and the BIOS ROM Information */
     InitializeBiosData();
     InitializeBiosInfo();
@@ -677,11 +701,6 @@
     /* Disable interrupts */
     setIF(0);
 
-    // FIXME: Check the word at 0040h:0072h (Bda->SoftReset) and do one of the
-    // following actions:
-    // - if the word is 1234h, perform a warm reboot (aka. Ctrl-Alt-Del);
-    // - if the word is 0000h, perform a cold reboot (aka. Reset).
-
     /* Do the POST */
     Bios32Post();