asm {
start:
	; xor ax, ax
	du8 0h31
	du8 0hC0

	; mov es, ax
	du8 0h8E
	du8 0hC0

	; mov ss, ax
	du8 0h8E
	du8 0hD0

	; mov ds, ax
	du8 0h8E
	du8 0hD8

	; mov sp, 0h7c00
	du8 0hBC
	du16 0h7c00

	; mov [boot_drive], dl
	du8 0h88
	du8 0h16
	du16 boot_drive

	mov ah, 0h41

	; mov bx, 0h55aa
	du8 0hBB
	du16 0h55aa
	int 0h13

	; jc ldns
	du8 0h0F
	du8 0h82
	du16 &ldns

	; call ldb2
	du8 0hE8
	du16 &ldb2

	; mov dl, [boot_drive]
	du8 0h8A
	du8 0h16
	du16 boot_drive

	; jmp 0h8000
	du8 0hEA
	du32 0h8000
}

asm {
ldb2:
	; mov si, b2dap
	du8 0hBE
	du16 b2dap

	; mov dl, [boot_drive]
	du8 0h8A
	du8 0h16
	du16 boot_drive

	mov ah, 0h42
	int 0h13

	; jc ldfail
	du8 0h0F
	du8 0h82
	du16 &ldfail 

	ret
}

asm {
ldfail:
	; mov si, ldfailmsg
	du8 0hBE
	du16 ldfailmsg

	; call print
	du8 0hE8
	du16 &print

	; jmp busyloop
	du8 0hE9
	du16 &busyloop
}

asm {
ldns:
	; mov si, ldfailmsg
	du8 0hBE
	du16 ldnsmsg

	; call print
	du8 0hE8
	du16 &print

	; jmp busyloop
	du8 0hE9
	du16 &busyloop
}

asm {
print:
	mov ah, 0h0e
print_loop:
	du8 0h8A ; mov al, [si]
	du8 0h04

	cmp al, 0h00

	; jz print_done
	du8 0h0F
	du8 0h84
	du16 &print_done

	int 0h10

	; inc si
	du8 0hFF
	du8 0hC6

	; jmp print_loop
	du8 0hE9
	du16 &print_loop
print_done:
	ret
}

asm {
busyloop:
	; jmp busyloop
	du8 0hE9
	du16 &busyloop
}
	
asm {
b2dap:
	du8 0h10
	du8 0
	du16 1
	du16 0h8000
	du16 0
	du64 1
}

asm {
boot_drive: du8 0

ldfailmsg: du8 "Boot failed! Can't load b2dap.", 13, 10, 0

ldnsmsg: du8 "Boot failed! LBA not supported.", 13, 10, 0
}