Write a procedure labeled flatten which should expect the address of the head node stored in register X$0$ and a memory location in register X$1($another address$).$ It should first write the length of the list to the provided memory location $($as a $64-$bit int$),$ and then copy the list as an array to the subsequent memory locations, storing each successive value in adjacent $8-$byte slots.

You may assume the existence of the procedure labeled count: as described above.

count:

mov x$7,0$

cbz x$0,$ end

loop:

add x$7,$ x$7,1$

ldr x$0,[$x$0,8]$

cbnz x$0,$ loop

end:

ret