Please Correct My Code ( Small Model )

[Lamya]

Hello Programmers

This Is My Question & the answer
But .. The out put not exist
i don't know what is the wrong with it

Write a program that will take as an input 5 Capital Letters and then display on next line in small letters and in reverse order.

• Use Logical operator to convert the capital letters to small letters.
• Save the input capital letters in an array named LETTERS.
• Use only indexed addressing mode.


My Answer :





.MODEL SMALL
.STACK 100H

.DATA

CR EQU 0DH ;Carriage Return
LF EQU 0AH ;Line Feed

MSG1 DB CR,LF,'Please Enter Capital letters: $'
MSG2 DB CR,LF,'Small Letters in reverse order: $'
LETTERS DB ?

.CODE

MAIN PROC

MOV AX,@DATA ;get data segment
MOV DS,AX ;initialize DS


;Display MSG1

LEA DX,MSG1 ;load address of MSG1 message
MOV AH,9 ;select string output
INT 21H ;output MSG

;Read the input from the user

;AND LETTERS,0H
MOV AH,1
MOV CL,5

WHILE_:

INT 21H
MOV LETTERS,AL
DEC CL
JCXZ PRO_
CMP AL,0DH
JNE WHILE_

PRO_:
XOR SI,SI
ARR:
CMP LETTERS[SI],' '
JE NEXT
XOR LETTERS[SI],0DFH

NEXT:
DEC SI
LOOP ARR

;Display MSG2

LEA DX,MSG2 ;load address of MSG2 message
MOV AH,9 ;select string output
INT 21H ;output MSG


MOV AH,9
LEA SI,LETTERS

READ:

INT 21H
ADD SI,2 ; IN CASE IT IS 2
LOOP READ


EXIT:
MOV AH,4CH ;DOS exit
INT 21H

MAIN ENDP ;ENDP ends a procedure
END MAIN ;END ends the source program

[Lamya]

The OutPut Should Be :

Please Enter Capital letters: ABCDE
Small Letters in reverse order: edcba

[Trep]

Going from capital to lowercase and back to capital is as easy as subtracting or adding the difference in ascii values. Check an ascii table

[TheDevilsFather]

I am tired .. i might come back and do it all complete ..but here is a test so you can see ..how to get it done ..

mov   AL , ARRAY_OF_CHAR   
sub    AH, AH 

LOOP:

cmp  BYTE [AL+AH] , 0 
je      REVERSE_STRING

add  [AL+AH] , 20H
add  AH, 4 
inc    CL 
jmp   LOOP

REVERSE_STRING:

dec  CL 
sub  AH, 4 

PUTCHAR [AL+AH]

cmp BYTE CL , 0
je     DONE 

jmp  REVERSE_STRING

Hope it helps




[/code]