Convert Character to binary assembly language

Question

Hi i m using dosbox and masm compilor. I want to prompts the user to enter a character, and prints the ASCII code of the character in hex and in binary on the next line. Rep

Answer 1

Ok, Sarah, I made the changes to your code, now it displays binary, I added two variables, all the changes are pointed by little ◄■ arrows :

 .MODEL SMALL
 .STACK 100H

  .DATA
   PROMPT_1  DB  0DH,0AH,'Enter the character : $'
   PROMPT_2  DB  0DH,0AH,'The ASCII code of the given number in HEX       form     is : $'
   PROMPT_3  DB  0DH,0AH,'The ASCII code of the given number in BIN       form     is : $'
   MY_CHAR   DB  ?          ; ◄■ char entered by user.
   BINARY    DB  9 DUP('$') ; ◄■ zeroes and ones.

 .CODE
  MAIN PROC
 MOV AX, @DATA                ; initialize DS  
 MOV DS, AX

 @START:                      ; jump label 
   LEA DX, PROMPT_1           ; load and display the string PROMPT_1
   MOV AH, 9
   INT 21H

   MOV AH, 1                  ; read a character
   INT 21H                                      

   MOV MY_CHAR, AL ; ◄■ save char to use in binary conversion.
   MOV BL, AL                 ; move AL to BL

   CMP BL, 0DH                ; compare BL with CR
   JE @END                    ; jump to label @END if BL=CR

   LEA DX, PROMPT_2           ; load and display the string PROMPT_2
   MOV AH, 9
   INT 21H

   XOR DX, DX                 ; clear DX
   MOV CX, 4                  ; move 4 to CX

   @LOOP_1:                   ; loop label
     SHL BL, 1                ; shift BL towards left by 1 position
     RCL DL, 1                ; rotate DL towards left by 1 position
                              ; through carry
   LOOP @LOOP_1               ; jump to label @LOOP_1 if CX!=0

   MOV CX, 4                  ; move 4 to CX

   @LOOP_2:                   ; loop label
     SHL BL, 1                ; shift BL towards left by 1 position
     RCL DH, 1                ; rotate DH towards left by 1 position
                              ; through carry
   LOOP @LOOP_2               ; jump to label @LOOP_2 if CX!=0

   MOV BX, DX                 ; move DX to BX
   MOV CX, 2                  ; initialize loop counter

   @LOOP_3:                   ; loop label
     CMP CX, 1                ; compare CX wiht 1
     JE @SECOND_DIGIT         ; jump to label @SECOND_DIGIT if CX=1
     MOV DL, BL               ; move BL to DL
     JMP @NEXT                ; jump to label @NEXT

     @SECOND_DIGIT:           ; jump label
       MOV DL, BH             ; move BH to DL

     @NEXT:                   ; jump label

     MOV AH, 2                ; set output function

     CMP DL, 9                ; compare DL with 9
     JBE @NUMERIC_DIGIT       ; jump to label @NUMERIC_DIGIT if DL<=9
     SUB DL, 9                ; convert it to number i.e. 1,2,3,4,5,6
     OR DL, 40H               ; convert number to letter i.e. A,B...F
     JMP @DISPLAY             ; jump to label @DISPLAY

     @NUMERIC_DIGIT:          ; jump label
       OR DL, 30H             ; convert decimal to ascii code

     @DISPLAY:                ; jump label
       INT 21H                ; print the character
   LOOP @LOOP_3               ; jump to label @LOOP_3 if CX!=0


;▼ FROM CHAR TO BINARY ▼
     LEA SI, BINARY+7 ; ◄■ point to string in data segment.
     MOV CX, 8        ; ◄■ maximum number of binary digits.
   @BIN_CONVERSION:
     SHR MY_CHAR,1    ; ◄■ get rightmost bit.
     JC  @BIT1
     MOV [BYTE PTR SI], '0'
     JMP @BIN_SKIP
   @BIT1:
     MOV [BYTE PTR SI], '1'
   @BIN_SKIP:
     DEC SI
     LOOP @BIN_CONVERSION

     LEA DX, PROMPT_3 ; ◄■ display message.
     MOV AH, 9
     INT 21H         
     LEA DX, BINARY   ; ◄■ display binary.
     MOV AH, 9
     INT 21H         

   JMP @START                 ; jump to label @START

 @END:                        ; jump label

 MOV AH, 4CH                  ; return control to DOS
 INT 21H
 MAIN ENDP
 END MAIN