From 53801b9baed096e57b40df6147d9ff0f3da0c737 Mon Sep 17 00:00:00 2001
From: Benji Dial <benji3.141@gmail.com>
Date: Sat, 16 May 2020 13:25:46 -0400
Subject: Hello world

---
 src/boot.asm | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 src/boot.asm

(limited to 'src/boot.asm')

diff --git a/src/boot.asm b/src/boot.asm
new file mode 100644
index 0000000..b476581
--- /dev/null
+++ b/src/boot.asm
@@ -0,0 +1,55 @@
+bits 16
+org 0x7c3e
+
+kernel_sectors equ 16
+kernel_segment equ 0x3000
+
+  in al, 0x92
+  or al, 0x02
+  out 0x92, al
+
+  xor ax, ax
+  mov ss, ax
+  mov sp, 0x7ffc
+
+  mov ax, kernel_segment
+  mov es, ax
+  mov ax, 0x0200 + kernel_sectors
+  xor bx, bx
+  mov cx, 0x0002
+  xor dh, dh
+  int 0x13
+
+  cli
+
+  lgdt [gdt]
+
+  mov eax, cr0
+  or al, 0x01
+  mov cr0, eax
+
+  jmp 0x08:pmode
+
+bits 32
+
+pmode:
+  mov ax, 0x10
+  mov ds, ax
+  mov ax, 0x18
+  mov ss, ax
+  mov sp, 0x7ffc
+
+  jmp kernel_segment * 16
+
+gdt:
+  dw .e - .t
+  dd .t
+.t:
+  dq 0x0000_0000_0000_0000
+  dq 0x00c0_9a00_0000_007f
+  dq 0x00c0_9200_0000_007f
+  dq 0x0040_9203_8000_7fff
+.e:
+
+times $$ + 448 - $ db 0
+dw 0xaa55
\ No newline at end of file
-- 
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