From a2eddaeba89be357d74c6758f370374eb75a3247 Mon Sep 17 00:00:00 2001
From: "E. Almqvist" <elalmqvist@gmail.com>
Date: Wed, 13 Jan 2021 11:59:13 +0100
Subject: [PATCH] Updated print sr to work

---
 src/bootloader.asm | 35 +++++++++++------------------------
 src/elib/io.asm    | 43 +++++++++++++++++++++++++------------------
 2 files changed, 36 insertions(+), 42 deletions(-)

diff --git a/src/bootloader.asm b/src/bootloader.asm
index 53ff58a..226de1b 100644
--- a/src/bootloader.asm
+++ b/src/bootloader.asm
@@ -1,32 +1,19 @@
+[org 0x7c00] ; bootsector
+
+jmp $  ; inf loop
+
+;; includes
+; EQU
 %include "equ/BIOS.asm"
 %include "equ/ASCII.asm"
 
 ; eLIB
-;; %include "elib/io.asm"
-
-mov ah, BIOS_MODE_TELETYPE ; enter teletype mode (BIOS)
-
-mov al, ASCII_LINEBREAK ; linebreak
-int BIOS_INT
-
-;; test db "Welcome to eOS", ASCII_CARRIAGE_RETURN, ASCII_LINEBREAK 
-
-; Print "eOS"
-;; mov rcx, test
-;; call print
-
-; ALPHABET PRINT TEST
-mov al, 64 ; one less than A since we are printing in a loop and it increments before sys interupt
-loop:
-	; Print the alphabetic char
-	inc al ; move to next char
-	int BIOS_INT ; bios interupt to print it
-
-	cmp al, 90 ; 26 letters in english alphabet (64 + 26)
-	jl loop ; if al < 64+26: jmp loop
-
+;%include "elib/io.asm"
 
-jmp $ 
+;; Data
+welcomeString:
+	db "Welcome to eOS", ASCII_CARRIAGE_RETURN, ASCII_LINEBREAK
 
+; Magic BIOS number 
 times 510-($-$$) db 0
 db 0x55, 0xaa
diff --git a/src/elib/io.asm b/src/elib/io.asm
index 5607c03..fa9eb6d 100644
--- a/src/elib/io.asm
+++ b/src/elib/io.asm
@@ -1,27 +1,34 @@
 ; eLibrary
 ; Input/Output subroutines
 
-; String structure
-; ASCII Offset = 8 bits
-; Array of the char  bytes, ending with 0 (ASCII_END)
+; Subroutine to print a string
+print:
+	pusha ; save current state of registers
 
-eLIB_STR_OFFSET equ 8 ; 8 bits
+	printLoop:
+		; Char check
+		mov al, [bx] ; load the char
+		cmp al, ASCII_END ; check if end of string
+		je return ; if al == ASCII_END then return end | lua is good psuedo-code
 
-print:	; Subroutine to print strings (from stack)
-	; Input: RCX, takes pointer to string from stack
-	pop rcx
 
-	; rcx now holds the starting point (address)
+		; BIOS Printing
+		mov ah, BIOS_MODE_TELETYPE ; enter tty mode
+		int BIOS_INT ; interupt and print the char (from line 10)
 
-	printLoop:
-		; Print the char
-		mov al, [rcx] ; dereference address to get value
-		cmp al, ASCII_END ; check if ASCII end
-		je printExit ; if reached the end then return
+		; Preperation for next iteration
+		inc bx ; increment the pointer to get next char
+		jmp printLoop ; repeat 
+
+	return:
+		popa ; restore all registers
+		ret ; return to previous location
 
-		int BIOS_INT ; system interupt (print string)
-		add rcx, eLIB_STR_OFFSET ; increase with offset
-		jmp printLoop ; loop for next char
+; Subroutine to print a string on a new line
+newline:
+	db ASCII_CARRIAGE_RETURN, ASCII_LINEBREAK
 
-	printExit:
-		ret
+println:
+	; Print the newline
+	mov bx, newline
+	call print