[aandrejevic] 75643: [NTVDM]: Fix linear 4-bpp mode. Return the status of the AC palette when the index register is read.

Author: aandrejevic
Date: Wed Aug 23 04:44:55 2017
New Revision: 75643

URL: http://svn.reactos.org/svn/reactos?rev=75643&view=rev
Log:
[NTVDM]: Fix linear 4-bpp mode. Return the status of the AC palette when the index
register is read.


Modified:
    trunk/reactos/subsystems/mvdm/ntvdm/hardware/video/svga.c

Modified: trunk/reactos/subsystems/mvdm/ntvdm/hardware/video/svga.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/subsystems/mvdm/ntvdm/hard…
==============================================================================
--- trunk/reactos/subsystems/mvdm/ntvdm/hardware/video/svga.c	[iso-8859-1] (original)
+++ trunk/reactos/subsystems/mvdm/ntvdm/hardware/video/svga.c	[iso-8859-1] Wed Aug 23
04:44:55 2017
@@ -847,10 +847,10 @@
                             /* 4-bits per pixel */
 
                             PixelData = VgaMemory[WRAP_OFFSET((Address + (X /
(VGA_NUM_BANKS * 2))) * AddressSize)
-                                                  * VGA_NUM_BANKS + (X %
VGA_NUM_BANKS)];
+                                                  * VGA_NUM_BANKS + ((X / 2) %
VGA_NUM_BANKS)];
 
                             /* Check if we should use the highest 4 bits or lowest 4 */
-                            if (((X / VGA_NUM_BANKS) % 2) == 0)
+                            if ((X % 2) == 0)
                             {
                                 /* Highest 4 */
                                 PixelData >>= 4;
@@ -1176,7 +1176,7 @@
             return VgaFeatureRegister;
 
         case VGA_AC_INDEX:
-            return VgaAcIndex;
+            return VgaAcIndex | (VgaAcPalDisable ? 0x20 : 0x00);
 
         case VGA_AC_READ:
             return VgaAcRegisters[VgaAcIndex];