From 59364518fd52ccb57de3bf124d82b00473384f4f Mon Sep 17 00:00:00 2001
From: "E. Almqvist" <elalmqvist@gmail.com>
Date: Tue, 12 Jan 2021 16:00:43 +0100
Subject: [PATCH] Little content

---
 BIOS_equ.asm   |  2 ++
 README.md      |  8 ++++++--
 bootloader.asm | 32 ++++++++++++++++++++++++++++++++
 start.sh       |  2 ++
 4 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100644 BIOS_equ.asm
 create mode 100755 start.sh

diff --git a/BIOS_equ.asm b/BIOS_equ.asm
new file mode 100644
index 0000000..0d13992
--- /dev/null
+++ b/BIOS_equ.asm
@@ -0,0 +1,2 @@
+; EQUs (lazy variables) for BIOS stuff
+BIOS_INT equ 0x10
diff --git a/README.md b/README.md
index 13477ee..81f908c 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,8 @@
 # eOS
-A simple and operating system
+A simple x86_64 operating system. (BIOS)
 
-This operating system is in no way original nor do I recommend even taking a look at it. I am going of [this](https://tuhdo.github.io/os01/) book. I highly recommend it! :) 
+This operating system is in no way original nor do I recommend even taking a look at it. I am going of  unfinished book. 
+
+## Books
+[Operating Systems: From 0 to 1](https://tuhdo.github.io/os01/) (Open-Source, unfinished)
+[Writing a Simple Operating System - from Scratch](https://www.cs.bham.ac.uk/~exr/lectures/opsys/10_11/lectures/os-dev.pdf)
diff --git a/bootloader.asm b/bootloader.asm
index d452c43..960ba59 100644
--- a/bootloader.asm
+++ b/bootloader.asm
@@ -1,3 +1,35 @@
+%include "BIOS_equ.asm"
+mov ah, 0x0e ; enter teletype mode (BIOS)
+
+mov al, "e"
+int BIOS_INT 
+
+mov al, "O"
+int BIOS_INT
+
+mov al, "S"
+int BIOS_INT
+
+mov al, 10 ; linebreak
+int BIOS_INT
+
+; ALPHABET PRINT
+
+
+mov al, 64 ; one less than A since we are printing in a loop and it increments before sys interupt
+loop:
+	inc al ; move to next char
+	int BIOS_INT ; bios interupt to print it
+	push al ; push al onto stack
+
+	mov al, 10 ; ASCII linebreak
+	int BIOS_INT 
+
+	pop al ; return to char
+
+	cmp al, 91 ; 26 letters in english alphabet (65 + 26)
+	jl loop ; if al < 65+26: jmp loop
+
 jmp $ 
 
 times 510-($-$$) db 0
diff --git a/start.sh b/start.sh
new file mode 100755
index 0000000..8cb51ad
--- /dev/null
+++ b/start.sh
@@ -0,0 +1,2 @@
+#!/usr/bin/bash
+qemu-system-x86_64 bin/bootloader.bin