Using AND convert lower alphabets into upper ~ Assembly Programs

This Program Use AND operator to Convert lower alphabets into upper
x y x^y
1 0 0
0 0 0
1 1 1
0 1 0

include irvine32.inc
.data

alp byte ?
msg byte "Please Enter an Alphabet to Make it in upper latter: ",0,13h,10h
msg1 byte "In upper Latter: ",0,13h,10h
msg2 byte "Latter is : ",0,13h,10h
msg3 byte "Binary is : ",0,13h,10h
msg4 byte "ASCII is : ",0,13h,10h

.code
main proc
call clrscr
call crlf
mov edx,offset msg
call writestring
call crlf
call crlf
mov edx,offset msg2
call writestring
mov edx,offset alp
call readchar

call writechar
call crlf
mov edx,offset msg3
call writestring
call writebin
call crlf
mov edx,offset msg4
call writestring
call writedec

call crlf
AND al,11011111b
call crlf
mov edx,offset msg1
call writestring
call crlf
mov edx,offset msg3
call writestring

call writebin
call crlf
mov edx,offset msg2
call writestring
call writechar
call crlf
mov edx,offset msg4
call writestring
call writedec

exit
main endp
end main