; NOF_SECTORS_STAGE2
NOF_SECTORS_STAGE2 equ 5

; IN dx: hex value to print	
print_hex:
	push bx
	push si
	mov si, HEX_TEMPLATE
	mov bx, dx
	shr bx, 12
	mov bx, [HEXABET+bx]
	mov [HEX_TEMPLATE+2], bl
	mov bx, dx
	and bx, 0x0FFF
	shr bx, 8
	mov bx, [HEXABET+bx]
	mov [HEX_TEMPLATE+3], bl
	mov bx, dx
	and bx, 0x00FF
	shr bx, 4
	mov bx, [HEXABET+bx]
	mov [HEX_TEMPLATE+4], bl
	mov bx, dx
	and bx, 0x000F
	mov bx, [HEXABET+bx]
	mov [HEX_TEMPLATE+5], bl
	call print_string
	pop si
	pop bx
	ret

HEX_TEMPLATE:
	db '0x???? ', 0

HEXABET:
	db '0123456789ABCDEF'

print_newline:
	push ax
	mov al, 10
	call print_char
	mov al, 13
	call print_char
	pop ax
	ret

; IN si
print_string:
	push ax
.loop:
	lodsb
	cmp al, 0
	je .fini
	call print_char
	jmp .loop
.fini:
	pop ax
	ret

; IN al: character to print
; MOD ah
print_char:
	mov ah, 0x0e
	int 0x10
	ret

fat_cursor:
	push ax
	push cx
	mov ah, 0x01
	mov cx, 0x0007
	int 0x10
	pop cx
	pop ax
	ret

; OUT: current row
current_row:
	push ax
	push bx
	push cx
	mov ah, 0x03
	mov bh, 0
	int 0x10
	pop cx
	pop bx
	pop ax
	ret

; IN dl: drive to read from
read_stage2_from_disk:
	mov ah, 0x02			; read sectors from drive
	
	mov al, NOF_SECTORS_STAGE2	; read sectors of stage 2
	mov ch, 0			; select first cylinder
	mov dh, 0			; first head
	mov cl, 2			; second sector after boot sector
	
	mov bx, 0			; where to store the data
	mov es, bx
	mov bx, 0x7e00			; 512 bytes after first sector
		
	int 0x13
	
	jc .read_error
	
	cmp al, NOF_SECTORS_STAGE2	; correct number of sectors read?
	jne .short_read			; if not, short read
	
	ret
	
.read_error:
	mov si, DISK_ERROR
	call print_string
	mov dh, 0
	mov dl, ah
	call print_hex
	jmp $

.short_read:
	mov si, SHORT_READ
	call print_string
	jmp $