Merge pull request #1 from E-Almqvist/dev

Pull dev branch

src/bootloader.asm

@@ -1,50 +1,21 @@
-%include "equ/BIOS.asm"
-%include "equ/ASCII.asm"
-
-mov ah, BIOS_MODE_TELETYPE ; enter teletype mode (BIOS)
-
-mov al, ASCII_LINEBREAK ; linebreak
-int BIOS_INT
-
-; Print "eOS"
-mov al, "e"
-int BIOS_INT 
-
-mov al, "O"
-int BIOS_INT
-
-mov al, "S"
-int BIOS_INT
+[org 0x7c00] ; bootsector
 
-mov al, ASCII_CARRIAGE_RETURN
-int BIOS_INT
+mov bx, welcomeString ; Print the welcome string
+call println
 
-mov al, ASCII_LINEBREAK ; linebreak
-int BIOS_INT
+jmp $  ; inf loop
 
-; ALPHABET PRINT
-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
-	
-	push ax ; push ax onto stack
-
-	; newline
-	mov al, ASCII_CARRIAGE_RETURN
-	int BIOS_INT
-	mov al, ASCII_LINEBREAK 
-	int BIOS_INT 
-
-	; Prepair for next iteration
-	pop ax ; restore
-
-	cmp al, 90 ; 26 letters in english alphabet (64 + 26)
-	jl loop ; if al < 64+26: jmp loop
+;; includes
+; EQU
+%include "equ/BIOS.asm"
+%include "equ/ASCII.asm"
 
+; eLIB
+%include "elib/io.asm"
 
-jmp $ 
+;; Data
+welcomeString: db "Welcome to eOS", ASCII_END
 
+; Magic BIOS number 
 times 510-($-$$) db 0
 db 0x55, 0xaa

src/elib/io.asm

@@ -1,2 +1,42 @@
 ; eLibrary
-; Input/Output sr
+; Input/Output subroutines
+
+; Subroutine to print a string
+print:
+	pusha ; save current state of registers
+
+	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
+
+
+		; BIOS Printing
+		mov ah, BIOS_MODE_TELETYPE ; enter tty mode
+		int BIOS_INT ; interupt and print the char (from line 10)
+
+		; 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
+
+
+newline: db ASCII_CARRIAGE_RETURN, ASCII_LINEBREAK, ASCII_END ; used for printing newlines
+
+; Subroutine to print a string on a new line
+println:
+	pusha
+
+	; Print the input string
+	call print ; this will print whatever is in [bx], so clear it if you dont want to print anything
+
+	; Print the newline
+	mov bx, newline
+	call print
+
+	popa
+	ret