org 0x7c00

xor ax, ax
jmp 0:start
start:
mov di, 0x7c00
mov ds, ax
; Setup stack to grow down from our start address
mov ss, ax
mov sp, di

; Store interrupt opcode on stack
mov ax, 0x13CD ; opcode for int 13h
push ax

; QWORD block number
push ss ; 0
push ss ; 0
push ss ; 0
mov ax, 63 ; fill in the starting sector of the FAT partition
push ax

; DWORD target address
push ss ; segment 0
push di ; offset 0x7c00

; WORD block count
mov ax, 1
push ax

; BYTE zero
; BYTE 0x10 bytes for read packet
mov ax, 0x10
push ax

; Setup SI for int13
mov si, sp

; Jump into stack where int 13h invocation is
mov ah, 0x42
jmp 0:0x7bfe

; Interrupt will return into new bootsector

times (446 - ($-$$)) db 0