to find no of ones and zeroz

;title:to find no of ones and zeroz
.model small
.data
a db 05H
num db ? ;stores input no
.code
start:
mov ax,@data
mov ds,ax
mov dx,0000H
mov cx,0000H
mov bx,08H ;storing 8 in bx counter
mov al,num
back:ror ax,1 ;rotate al by 1
jnc abc ;jump if carry
inc dx ;increment dx
abc:inc cx
dec bx
jnz back ;jump if zero
mov ax,4c00h
int 21h
end start

;output
;input nos 0000 0101
no of 0s:Cx:6
no of 1s:Dx:2