assembly - How to Slide numbers in an array? -

i trying slide numbers array
example, array 8,7,6,5,4,3,2,1 , when code finishes loop, should 1,8,7,6,5,4,3,2, not sure how that

.model small .data     arr db 8,7,6,5,4,3,2,1   .code .startup    mov cx,8    mov si ,7      lop:    mov al ,arr[si]      mov bl ,arr[si-1]     mov arr[si], bl    mov arr[si-1], al     dec si   loop lop  .exit 

that drag last element thorough whole array:

.model small .data     arr db 8,7,6,5,4,3,2,1   .code .startup   mov cx , 7           ; here: 1 less ( shift size-1 elements)   mov si , 7      lop:    mov  al,arr[si-1]    xchg al, arr[si]    mov  arr[si-1], al    dec si  loop lop  .exit 

can't possibly imagine why need kind of algorithm, still.