[BITS 64]

global _start
_start:

sub rsp, 0x100

mov qword [rsp], 16

lea rdx, [rsp]
lea rsi, [rsp+8]
mov rdi, 3
mov rax, 43
syscall
mov rbp, rax

mov rdi, 4
call write_marker

; set_filename
mov rdx, 9
mov rsi, rsp
mov rdi, rbp
mov rax, 0
syscall

call write_marker

; read_file
mov rdx, 5
mov rsi, rsp
mov rax, 0
syscall

call write_marker

; set_xor_key
mov rdx, 5
mov rsi, rsp
mov rax, 0
syscall

mov edx, [rsi+1]
mov rsi, rsp
mov rax, 0
syscall

mov rdi, 4
mov rax, 1
syscall
int3

write_marker:
  lea rsi, [rel marker]
  mov rdx, 4
  mov rax, 1
  syscall
  ret

marker:
  db 0x0a,'OK',0x0a