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An Assembly Language Program that will prompt the user to enter a hex digit character ( “0”…”9″ or “A”…”F” ), display it on the next line in decimal, and ask the user if he or she wants to do it again. If the user types “y” or “Y”, the program repeats; if the user types anything else, the program terminates, If the user enters an illegal character, prompt the user to try again
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.MODEL SMALL .STACK 100H .DATA PROMPT DB 'Enter a HEX digit : $' DECIMAL DB 'The equivalent Decimal digit is : $' CONTINUE DB 'Do you want to do it again : $' ILLEGAL DB 'Illegal Character - Enter 0..9 or A..F : $' NEXT_LINE DB 0DH,0AH,"$" .CODE MAIN PROC MOV AX, @DATA ; initialize DS MOV DS, AX @START_1: ; jump label MOV AH, 9 ; set string output function LEA DX, PROMPT ; load and display the string PROMPT INT 21H @START_2: ; jump label MOV AH, 1 ; read a character INT 21H MOV BL, AL ; save the character into BL CMP BL, "A" ; compare BL with "A" JB @SINGAL_DIGIT ; jump to label @SINGAL_DIGIT if BL<A CMP BL, "F" ; compare BL with "F" JA @ILLEGAL_CHARACTER ; jump to label @ILLEGAL_CHARACTER if BL>F JMP @GREATER_THAN_NINE ; jump to label @GREATER_THAN_NINE @SINGAL_DIGIT: ; jump label CMP BL, "0" ; comapre BL with "0" JB @ILLEGAL_CHARACTER ; jump to label @ILLEGAL_CHARACTER if BL<0 CMP BL, "9" ; compare BL with "9" JA @ILLEGAL_CHARACTER ; jump to label #ILLEGAL_CHARACTER if BL>9 JMP @LESS_THAN_TEN ; jump to label @LESS_THAN_TEN @ILLEGAL_CHARACTER: ; jump label MOV AH, 9 ; set string output function LEA DX, NEXT_LINE ; load and display the string NEXT_LINE INT 21H LEA DX, ILLEGAL ; load and display the string ILLEGAL INT 21H JMP @START_2 ; jump to label @START_2 @LESS_THAN_TEN: ; jump label MOV AH, 9 ; set string output function LEA DX, NEXT_LINE ; load and display the string NEXT_LINE INT 21H LEA DX, DECIMAL ; load and display the string DECIMAL INT 21H MOV AH, 2 ; print the contents of BL MOV DL, BL INT 21H JMP @CONTINUE ; jump to label @CONTINUE @GREATER_THAN_NINE: ; jump label MOV AH, 9 ; set string output function LEA DX, NEXT_LINE ; load and display the string NEXT_LINE INT 21H LEA DX, DECIMAL ; load and display the string DECIMAL INT 21H MOV AH, 2 ; display the digit 1 MOV DL, 31H INT 21H SUB BL, 11H ; subtract 11H from BL to find 2nd digit MOV DL, BL ; display the 2nd digit INT 21H @CONTINUE: ; jump label MOV AH, 9 ; set string output function LEA DX, NEXT_LINE ; load and display the string NEXT_LINE INT 21H INT 21H LEA DX, CONTINUE ; load and display the string CONTINUE INT 21H MOV AH, 1 ; read a character INT 21H CMP AL, "y" ; compare AL with "y" JE @JUMP ; jump to label @JUMP if AL=y CMP AL, "Y" ; compare AL with "Y" JE @JUMP ; jump to label @JUMP if AL=Y JMP @END ; jump to label @END @JUMP: ; jump label LEA DX, NEXT_LINE ; load and display the string NEXT_LINE MOV AH, 9 INT 21H INT 21H JMP @START_1 ; jump to label @START_1 @END: ; jump label MOV AH, 4CH ; return control to DOS INT 21H MAIN ENDP END MAIN |