From d9199842084865b0d9f33b31289d92bc0c3fbbb0 Mon Sep 17 00:00:00 2001
From: Michal Idziorek <m.i@gmx.at>
Date: Sun, 31 Aug 2014 15:49:25 +0200
Subject: Moved enable_a20 back to bootloader

---
 boot/mbr.asm | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'boot/mbr.asm')

diff --git a/boot/mbr.asm b/boot/mbr.asm
index bb74d23..4a75e3e 100644
--- a/boot/mbr.asm
+++ b/boot/mbr.asm
@@ -141,6 +141,14 @@ boot_16:
 boot_32_pm:
 ;
 
+;    ;enable A20
+;    ;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
 ;
     call KERNEL_OFFSET			        ;jump into our Kernel!
 ;
-- 
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