From ed0f5cc05b8e4c9b6d2c4ab22a9556aa9be37a97 Mon Sep 17 00:00:00 2001
From: "E. Almqvist" <elalmqvist@gmail.com>
Date: Fri, 6 Aug 2021 22:26:57 +0200
Subject: [PATCH] GDT

---
 src/pm/gdt.asm | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 src/pm/gdt.asm

diff --git a/src/pm/gdt.asm b/src/pm/gdt.asm
new file mode 100644
index 0000000..cfe2a75
--- /dev/null
+++ b/src/pm/gdt.asm
@@ -0,0 +1,20 @@
+; GDT
+
+gdt_start:
+
+gdt_null:		; NULL descriptor
+	dd 0x0		; 4-bytes of 
+	dd 0x0		; 0x0 (0) = NULL
+
+gdt_code: 		; Code SD
+	; Range: 	0x0 - 0xfffff
+	; Flags1: 	1001b (present:2 privilege:descriptor type)
+	; Type:		1010b (code:conforming:readable:accessed)
+	; Flags2:	1100b (granularity:32bit default:64bit seg:AVL)
+
+	dw 0xffff		; Limit (bits 0-15)
+	dw 0x0			; Base (bits 0-15)
+	dw 0x0			; Base (bits 16-23)
+	db 10011010b 	; Flags1 : Type
+	db 11001111b	; Flags2 : Limit (16-19)
+	db 0x0			; Base (bits 24-31)