diff --git a/messages.asm b/messages.asm
index 529b262..7eb7a7b 100644
--- a/messages.asm
+++ b/messages.asm
@@ -6,7 +6,7 @@ HEIGHT equ 0x18			; 24
 VIDEO_MODE equ 0x3		; 80x25 screen, text mode
 
 PIT_MODECOMMAND_PORT equ 0x43	; programmable interval timer mode/command port (used for speaker)
-PIT_CH2_DATA_PORT equ 0x42		; PIT channel 2 data port
+PIT_CH2_DATA_PORT equ 0x42	; PIT channel 2 data port
 
 ;; see http://www.ctyme.com/intr/int-10.htm for interrupts
 
@@ -36,9 +36,9 @@ mov sp, 0x2000	; initialise stack pointer
 ;;	1 1	8
 
 ;; initialise serial port
-mov ah, 0x0				; initialise UART
+mov ah, 0x0		; initialise UART
 mov al, 0b111_00_0_11	; baud 9600, no parity, 1 stop bit, 8 data bits
-mov dx, 0x0				; COM1
+mov dx, 0x0		; COM1
 int 0x14
 
 ;; Use color mode
@@ -119,7 +119,7 @@ int 0x10
 ;; - ax
 ;; - bl
 change_color_mode:
-	call readbyte			; get byte from keyboard (in al)
+	call readbyte		; get byte from keyboard (in al)
 	mov [color_mode], al	; store byte in color_mode variable
 
 	jmp compare_virtual_and_jump
@@ -159,7 +159,7 @@ newline:
 beep:
 	call    read_duration	; get duration from keyboard (in al)
 	mov     ah, 0
-	push    ax				; store on stack
+	push    ax		; store on stack
 
 	;; move 182 (0b10 11 011 0) into al
 	;; bit 7-6 = channel select (2, PC speaker)
@@ -175,15 +175,15 @@ beep:
 	sal     ax, 5		; multiply by 32
 	add     ax, 1140
 
-	out     PIT_CH2_DATA_PORT, al		; Output low byte.
+	out     PIT_CH2_DATA_PORT, al	; Output low byte.
 	mov     al, ah
-	out     PIT_CH2_DATA_PORT, al		; Output high byte
+	out     PIT_CH2_DATA_PORT, al	; Output high byte
 
 	;; Port 0x61 does a whole lot but only the bottom 2 bits are relevant here
 	;; (speaker enable and speaker input select)
-	in      al, 0x61		; Preserve previous value
+	in      al, 0x61	; Preserve previous value
 	or      al, 00000011b	; Set bits 1 and 0 (enable speaker, input = channel 2)
-	out     0x61, al		; Send new value
+	out     0x61, al	; Send new value
 
 	;; mov     bx, 50000	; Pause for duration of note.
 
@@ -199,13 +199,13 @@ beep:
 .pause1:
 	mov     ecx, 65535
 .pause2:
-	dec     cx		; count down
+	dec     cx	; count down
 	jne     .pause2	; if not zero keep counting down
 
-	dec     bx		; decrement duration counter
+	dec     bx	; decrement duration counter
 	jne     .pause1	; keep doing that until it is 0
 
-	in      al, 0x61		; Preserve previous value
+	in      al, 0x61	; Preserve previous value
 	and     al, 11111100b	; Clear bits 1 and 0 (disable speaker, clear channel select)
 	out     0x61, al        ; Send new value
 
@@ -220,10 +220,10 @@ beep:
 ;; - dx
 nonewline:
 	;; Write character
-	mov ah, 0x09			; write character with attribute
-	mov bh, 0x00			; page number
+	mov ah, 0x09		; write character with attribute
+	mov bh, 0x00		; page number
 	mov bl, [color_mode]	; BIOS colour code
-	mov cx, 0x01			; amount of times to print character
+	mov cx, 0x01		; amount of times to print character
 	int 0x10
 
 	;; Get current cursor position
@@ -277,7 +277,7 @@ readbyte:
 	int 0x16
 
 	;; Read character is in al
-	sub al, 'a'		; Normalise
+	sub al, 'a'	; Normalise
 	mov bl, al
 	shl bl, 0x04	; First character is upper 4 bits