positive or negative

.model small
.stack 100h
.data
   num1 db -128 ; The number to check
   positive db "The number is positive $"
   negative db "The number is negative $"
   zero db "The number is zero $"
.code
main:
   mov ax, @data
   mov ds, ax
   mov al, num1
   cmp al, 0
   jg greater
   jl lower
   je zeros

greater:
   mov ah, 09h
   lea dx, positive
   int 21h
   jmp end

lower:
   mov ah, 09h
   lea dx, negative
   int 21h 
   jmp end

zeros:
   mov ah, 09h
   lea dx, zero
   int 21h

end:
   mov ah, 4Ch
   int 21h
end main