[org 0x0]       ; Offset zero is desired

jmp START       ; jump to executable code 

; definition of boot sector data for a diskette
        
BS_OEMName      db "MSWIN4.1"    ; 8 characters 
BPB_BytsPerSec  dw 0x0200        ; 512 bytes per sector
BPB_SecPerClus  db 0x01          ; one sector per cluster
BPB_RsvdSecCnt  dw 0x0001        ; one reserved sector
BPB_NumFATs     db 0x02          ; two FATs
BPB_RootEntCnt  dw 0x00E0        ; 224 entries 
BPB_TotSec16    dw 0x0B40        ; 2880 sectors on disk
BPB_Media       db 0xF0          ; media type code
BPB_FATSz16     dw 0x0009        ; 9 sectors in one FAT
BPB_SecPerTrk   dw 0x0012        ; 18 sectors per track
BPB_NumHeads    dw 0x0002        ; 2 heads
BPB_HiddSec     dd 0x00000000    ; no hidden sectors
BPB_TotSec32    dd 0x00000000    ; no FAT32 sectors
BS_DrvNum       db 0x00          ; drive number 0
BS_Reserved1    db 0x00          ; reserved
BS_BootSig      db 0x29          ; extended boot signature
BS_VolID        dd 0x12345678    ; serial number 
BS_VolLab       db "a_nice_disc" ; volume label 
BS_FilSysType   db "FAT12   "    ; file system 


%define MD_Get_MD_Status 0xf9	
%define MD_Write_Port	 0x70
%define MD_Read_Port	 0x71
%define MD_Bit_To_Test   0x08

	
START:				; start of CODE
	cli                     ; disable interrupts 

;; Enable 320x200 graphics mode
	mov 	eax,0x13	
	int 	0x10

;; Check if the button is pressed
	mov 	al,MD_Get_MD_Status
	out 	MD_Write_Port,al
	in 	al,MD_Read_Port
	test 	al,MD_Bit_To_Test
	mov	al,0x0
	out 	MD_Write_Port,al 
	jz 	set_red
	

;; Set green in first palette position
set_green:	
	mov	ax,0
        mov	dx,0x3c8	; Set first palette value
        out	dx,al
        inc	dx		; Palette is at 0x3c9
        mov	al,0x00		; Set red value
        out	dx,al		
        mov	al,0xff		; Set green value
        out	dx,al		
        mov	ax,0x0		; Set blue value
        out	dx,al		
	jmp	hang_here	


;; Set red in first palette position	
set_red:	
	mov	ax,0
        mov	dx,0x3c8	; Set first palette value
        out	dx,al
        inc	dx		; Palette is at 0x3c9
        mov	al,0xff		
        out	dx,al		; Set red value
        mov	al,0x0
        out	dx,al		; Set green value
        mov	ax,0x0
        out	dx,al		; Set blue value
	
	
hang_here:
	jmp hang_here
;; ----------------------
;; Finish up
;; ----------------------
	
times 512-($-$$)-2 db 0 ; make the code exactly 512 bytes
dw 0xAA55               ; the required final two bytes for a boot sector