[hbelusca] 64794: [NTVDM]: simplify code and add a reference link concerning the CrtColorPaletteMask mask.

Author: hbelusca
Date: Fri Oct 17 22:27:34 2014
New Revision: 64794

URL: http://svn.reactos.org/svn/reactos?rev=64794&view=rev
Log:
[NTVDM]: simplify code and add a reference link concerning the CrtColorPaletteMask mask.

Modified:
    trunk/reactos/subsystems/ntvdm/bios/vidbios.c

Modified: trunk/reactos/subsystems/ntvdm/bios/vidbios.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/subsystems/ntvdm/bios/vidb…
==============================================================================
--- trunk/reactos/subsystems/ntvdm/bios/vidbios.c	[iso-8859-1] (original)
+++ trunk/reactos/subsystems/ntvdm/bios/vidbios.c	[iso-8859-1] Fri Oct 17 22:27:34 2014
@@ -2652,9 +2652,9 @@
                 {
 #ifdef DOSBOX
                     BYTE Index = getBL();
-                    BYTE CrtColorPaletteMask = Bda->CrtColorPaletteMask;
-                    CrtColorPaletteMask = (CrtColorPaletteMask & 0xE0) | (Index &
0x1F);
-                    Bda->CrtColorPaletteMask = CrtColorPaletteMask;
+
+                    /* See: http://www.bioscentral.com/misc/bda.htm */
+                    Bda->CrtColorPaletteMask = (Bda->CrtColorPaletteMask &
0xE0) | (Index & 0x1F);
 
                     Index = ((Index << 1) & 0x10) | (Index & 0x7);
 
@@ -2666,7 +2666,7 @@
 
                     VgaSetSinglePaletteRegister(0x00, Index);
 
-                    Index = (CrtColorPaletteMask & 0x10) | 0x02 |
((CrtColorPaletteMask & 0x20) >> 5);
+                    Index = (Bda->CrtColorPaletteMask & 0x10) | 0x02 |
((Bda->CrtColorPaletteMask & 0x20) >> 5);
 
                     VgaSetSinglePaletteRegister(0x01, Index);
                     Index += 2;
@@ -2687,14 +2687,15 @@
                 case 0x01: /* Set Palette */
                 {
                     BYTE Index = getBL();
-                    BYTE CrtColorPaletteMask = Bda->CrtColorPaletteMask;
-                    CrtColorPaletteMask = (CrtColorPaletteMask & 0xDF) | ((Index
& 1) ? 0x20 : 0x0);
-                    Bda->CrtColorPaletteMask = CrtColorPaletteMask;
+
+                    /* See: http://www.bioscentral.com/misc/bda.htm */
+                    /* Reset bit 5: foreground colors index (0: green/red/yellow; 1:
cyan/magenta/white) */
+                    Bda->CrtColorPaletteMask = (Bda->CrtColorPaletteMask &
0xDF) | ((Index & 1) ? 0x20 : 0x00);
 
                     /* Don't set any extra colors when in text mode */
                     if (Bda->VideoMode <= 3) break;
 
-                    Index = (CrtColorPaletteMask & 0x10) | 0x02 | Index;
+                    Index = (Bda->CrtColorPaletteMask & 0x10) | 0x02 | Index;
 
                     VgaSetSinglePaletteRegister(0x01, Index);
                     Index += 2;