Character conversion (A=a)&&(a=A)

.MODEL SMALL
.stack 500h
.CODE

MAIN PROC

call indec
push ax
mov ah,2
mov dl,0dh
int 21h
mov dl,0ah
int 21h
pop ax
call outdec
mov ah,4ch
int 21h

MAIN ENDP
indec proc
push bx
push cx
push dx

begin:
mov ah,2
mov dl,'?'
int 21h

xor bx,bx
xor cx,cx

mov ah,1
int 21h
cmp al,'-'
je minus
cmp al,'+'
je plus
jmp repeat2

minus:
mov cx,1

plus:
int 21h


repeat2:
cmp al,'0'
jnge n_digit
cmp al,'9'
jnle n_digit

and ax,000fh
push ax
mov ax,10
mul bx
pop bx
add bx,ax


mov ah,1
int 21h
cmp al,0dh
jne repeat2


mov ax,bx
or cx,cx
je exit

neg ax

exit:
pop dx
pop cx
pop bx
ret

n_digit:
mov ah,2
mov dl,0dh
int 21h
mov dl,0ah
int 21h
jmp begin



indec endp

outdec proc
push ax
push bx
push cx
push dx
or ax,ax
jge @end_if1
push ax
mov dl,'-'
mov ah,2
int 21h
pop ax
neg ax
@end_if1:
xor cx,cx
mov bx,10d
@repeat1:
xor dx,dx
div bx
push dx
inc cx

or ax,ax
jne @repeat1

mov ah,2

@print_loop:
pop dx
or dl,30h
int 21h

loop @print_loop

pop dx
pop cx
pop bx
pop ax



outdec endp


END MAIN

indec and outdec proc

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