Convert single char Hex input to Binary in assembly code - intel 8086

hex to binary.asm

.model small
.stack 100h
.data
    countOne db ?
    countZero db ?
    nln db 0ah,0dh,'$'
    msg1 db 'Number of Ones: $'
    msg2 db 0ah,0dh,'Number of Twos: $'
.code
     main proc
     
     mov ax,@data
     mov ds,ax
     
     mov countOne,30h
     mov countZero,30h
     
     mov ah,1
     int 21h
     mov bl,al
     
     
     cmp bl,65
     jge hex
     
     sub bl,48
     jmp doit:
     
     hex:
     sub bl,55
     
     doit:
     mov ah,9
     lea dx,nln
     int 21h
     
     mov cl,0
             
     rotate:        
     rol bl,1
     
     jnc zero
     jc one
     
     zero:
     inc countZero
     
     cmp cl,4
     jl do1
     
     mov ah,2
     mov dl,'0'
     int 21h
     
     do1:
     jmp looper
     
     one:
     inc countOne
     
     cmp cl,4
     
     jl do2
     mov ah,2
     mov dl,'1'
     int 21h
     do2:
     jmp looper
     
     
     looper:
     inc cl
     cmp cl,8
     jl rotate
     
     
     finish:
     mov ah,9
     lea dx,nln
     int 21h
     
     mov ah,09
     lea dx,msg1
     int 21h
     
     mov dl,countOne
     mov ah,2
     int 21h
     
     mov ah,09
     lea dx,msg2
     int 21h
     
     mov ah,2
     mov dl,countZero
     int 21h
     

     main endp
end main