Q. Determine the use of LOOP instruction?

Program:This program prints the alphabets (A-Z)

; Register used: AX, CX, DX

CODE SEGMENT

ASSUME: CS: CODE.    

MAINP:          MOV   CX, 1AH                    ; 26 in decimal = 1A in hexadecimal Counter.

                        MOV   DL, 41H                     ; Loading DL with ASCII hexadecimal of A.

NEXTC:          MOV   AH, 02H                     ; display result character in DL

            INT      21H                            ; DOS interrupt 

            INC      DL                             ; Increment DL for next char

            LOOP NEXTC                       ; Repeat until CX=0. (Loop automatically decrements

                                                                        ; CS and checks whether it is zero or not)

                        MOV   AX, 4C00H                ; Exit DOS

                        INT      21H                            ; DOS Call

CODE ENDS

END MAINP