From 5348a94a6e7a16a070c502c29db30a08253a99a3 Mon Sep 17 00:00:00 2001
From: Michal Idziorek <m.i@gmx.at>
Date: Tue, 2 Sep 2014 14:53:09 +0200
Subject: Debugging paging problem on VirtualBox (VT-x)

---
 boot/mbr.asm | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

(limited to 'boot/mbr.asm')

diff --git a/boot/mbr.asm b/boot/mbr.asm
index 4ece914..ca851c3 100644
--- a/boot/mbr.asm
+++ b/boot/mbr.asm
@@ -61,7 +61,7 @@ jmp $ ;entry for other processors ;)
 BOOT_DRIVE:
     db 0xff
 STR_VERSION:
-    db "v0.4",0
+    db "v0.5",0
 VESA_CHECK1:
     db "1",0
 VESA_CHECK2:
@@ -145,17 +145,30 @@ boot_32_pm:
 ;    ;http://www.brokenthorn.com/Resources/OSDev9.html
 ;    ;Method 3.1: Enables A20 through keyboard controller
 ;    ;Not all keyboard controllers support this
-;    ;todo: check if this has any effect at all !?!?
-     mov al, 0xdd  ; command 0xdd: enable a20
-;   ;mov al, 0xdf  ; command 0xdf: disable a20
-     out 0x64, al  ; send command to controller
+;    ; does not work in virtual box (with VT-x accerleration?) 
 
-     mov eax,0
-;
+;     mov al, 0xdd  ; command 0xdd: enable a20
+;     mov al, 0xdf  ; command 0xdf: disable a20
+;     out 0x64, al  ; send command to controller
+
+    ;Fast A20 Gate:
+    ;http://wiki.osdev.org/A20_Line
+    
+    in al, 0x92
+    or al, 2
+    out 0x92, al
+
+    ; call kernel!
+    mov eax,0					;booting processor
     call KERNEL_OFFSET			        ;jump into our Kernel!
 ;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;
+
+;fill partition table (4x16byte) with zeroes. 
+;(otherwise my Acer Aspire will not boot)
+times 64 db 0x0
+
 ;so we get identified as MBR
 times 510-($-$$) db 0x0
 ;dw 0x0
-- 
cgit v1.2.3