.model small
.data
m1 db 0ah,0dh,'type a character :','$'
m2 db 0ah,0dh,'the ascii code of '
c1 db ?,' in hexa is ','$'
.code
main proc
mov ax,@data
;intialize ds
mov ds,ax
;------------
begin: mov ah,9
;prompt user
lea dx,m1
int 21h
mov ah,1
;read char.
int 21h
cmp al,0dh
;if cr exit

je out_
mov c1,al
;store char
.
mov bl,al
;take a copy of char
mov ah,9
;display 2

lea dx,m2


int 21h

mov cl,4
shr c1,cl
;prapare for display 1


;* note below
add c1,30h
;convert to char.

mov dl,c1
jmp exe1
continue: and bl,0fh
;convert 2


cmp bl,9
;if >9 mean a,b,c…..hex ch.
jg error_
add bl,30h
;convert to char
.
mov dl,bl
jmp exe2
exe1: mov ah,2
;1


int 21h
jmp continue
exe2: mov ah,2
int 21h


jmp begin
;ask if you want to do it again

;------------
error_: add bl,37h
;convert to a,b,c…. hexa ch
.
mov dl,bl
mov ah,2
;display it

int 21h

jmp begin
;ask if you want to do it again

out_: mov ah,4ch
;return to dos
int 21h
main endp
end main