Question

Write an Assembler Program to input a string from the keyboard, store the string in

memory. Your program should check and display if the string contains vowel letters (A, E, I, O, U),

Hint: your program should check both lower and upper case

Answer 1

Program:

.MODEL SMALL

.STACK 64

.DATA

MAXCHAR DB 60;

ACTCHAR DB ?;

STR DB 60 DUP (?);

VOWEL_NO DB 0;

NEWLN DB 0DH,0AH,”$”;

CHECK STR DB 65, 69, 73, 79, 85, 97, 101, 105, 111, 117; {A, B, …. Z = 65, 66 …. 90 : a, b, … z = 97, 98, …122}

.CODE

MAIN PROC

MOV AX, @DATA;                            initialize data segment

MOV DS, AX;                                      register

LEA DX, MAXCHAR;                         compute address of value

MOV AH, 0AH;                                   Getline function

INT 21H;                                               Get input

CALL NEXT LINE;                               New Line

MOV CL, ACTCHAR;

MOV CH, 0;

MOV, 0;

L1:          PUSH CX;                                             Save Register

MOV DL, STR[BX];

MOV CX, 10;

MOV SI, 0;

L3:          CMP DL, CHECK STR[SI];                compare DL and str[si]

JZ L2;                                                     jump to label L2 if CF = 1

INC SI;                                                   Add 1 to contents of SI register

LOOP L3;                                              Repeat until all elements adjusted

JMP L4;                                                 Jump to L4 without any condition

L2:          INC VOWEL_NO;                              Add 1 to content of Vowel no

MOV AH, 02H;                                   Put the immediate number

INT 21H;                                               Get input

L4:          INC BX;                                                 Add 1 to contents of BX register

POP CX;                                                Copy a word from the top of stack to CX

;                                               Increment SP by 2

LOOP L1;                                              Repeat until all elements adjusted

CALL VOWEL COUNT DISP

MOV AX, 4000H;                               Put the immediate number

INT 21H;                                               Get input

MAIN ENDP

NEXT LINE PROC NEAR;

LEA DX, NEWLN;                               compute address of value

MOV AH, 09H;                                   Put the immediate number

INT 21H;

RET;                                                       Return to main line

NEXTLINE ENDP

VOWEL COUNT DISP PROC NEW

MOV CX, 10;                                       Put the immediate number

MOV AL, VOWEL_NO;                    Copy word from Vowel no to AL Register

MOV AH, 0;                                         Put the immediate number

MOV BX, 0;                                         Put the immediate number

LABEL1: MOV DX, 0;                                        Put the immediate number

DIV CX;                                                 Divide doubleword in DX and AX by word in CX.

;                                     Quotient in AX, reminder in DX

ADD DX, 30H;                                     Add immediate number 30H to content of DX.

;                                     Result in AL

PUSH DX;                                             Decrement SP by 2, copy DX to stack

INC BX;                                                 Add 1 to contents of BX register

CMP AX, 0;                                          Compare by subtracting 0 from AX

JA LABEL1;                                           Jump to level LABEL1 if AX above 0

MOV AH, A2H;                                   Put the immediate number

MOV CX, BX;                                       Copy word from BX to CX Register

DISP:     POP DX;                                                Copy a word from the top of stack to DX

;                                               Increment SP by 2

INT 21H;                                               Get Input

LOOP DISP;                                         Repeat until all elements adjusted

RET;                                                       return to main program

VOWEL COUNT DISP ENDP

END MAIN;                                         End of main program