From e7339745af58e1b21da2fc20e9551cac4857a7b5 Mon Sep 17 00:00:00 2001
From: Aleksandar Andrejevic <aandrejevic@reactos.org>
Date: Thu, 25 Aug 2016 03:01:18 +0000
Subject: [PATCH] [NTVDM:BIOS] Implement VBE function AH = 0x05, "CPU Video
 Memory Control".

svn path=/trunk/; revision=72451
---
 .../subsystems/mvdm/ntvdm/bios/bios32/vbe.c   | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/reactos/subsystems/mvdm/ntvdm/bios/bios32/vbe.c b/reactos/subsystems/mvdm/ntvdm/bios/bios32/vbe.c
index 574c8e6775d..a006850b47e 100644
--- a/reactos/subsystems/mvdm/ntvdm/bios/bios32/vbe.c
+++ b/reactos/subsystems/mvdm/ntvdm/bios/bios32/vbe.c
@@ -525,6 +525,53 @@ VOID WINAPI VbeService(LPWORD Stack)
             break;
         }
 
+        /* CPU Video Memory Control */
+        case 0x05:
+        {
+            BYTE Window = getBL();
+            BYTE OldGcIndex = IOReadB(VGA_GC_INDEX);
+
+            switch (getBH())
+            {
+                /* Select Memory Window */
+                case 0:
+                {
+                    setAL(0x4F);
+
+                    if (getDH() != 0)
+                    {
+                        /* Offset too high */
+                        setAH(1);
+                        break;
+                    }
+
+                    IOWriteB(VGA_GC_INDEX, (Window == 0) ? SVGA_GC_OFFSET_0_REG : SVGA_GC_OFFSET_1_REG);
+                    IOWriteB(VGA_GC_DATA, getDL());
+
+                    setAH(0);
+                    break;
+                }
+
+                /* Return Memory Window */
+                case 1:
+                {
+                    IOWriteB(VGA_GC_INDEX, (Window == 0) ? SVGA_GC_OFFSET_0_REG : SVGA_GC_OFFSET_1_REG);
+                    setDX(IOReadB(VGA_GC_DATA));
+
+                    setAX(0x004F);
+                    break;
+                }
+
+                default:
+                {
+                    DPRINT("VESA INT 0x10, AH = 0x05, Unknown subfunction: %02X", getBH());
+                }
+            }
+
+            IOWriteB(VGA_GC_INDEX, OldGcIndex);
+            break;
+        }
+
         default:
         {
             DPRINT1("VESA BIOS Extensions function %02Xh NOT IMPLEMENTED!\n", getAL());