. f ~host

MOV word, OFFSET text    ; Moves the pointer to the address of the text
LOOP_START:
    LODSB                  ; Loads a byte from the address pointed by SI into AL
    CMP AL, 0              ; Compares the loaded byte with zero
    JE END_LOOP            ; Jumps to END_LOOP if the byte is zero
    ; Your byte processing code here
    JMP LOOP_START         ; Jumps to the next byte
END_LOOP:
    ; Your code after loop completion here