lc3 assembly language program to read 3 chars and dispaly in upper case chars

lc3 assembly language program to read 3 chars and dispaly in upper case chars
.orig x3050
lea r0,msg
puts
ld r0,num1
add r0,r1,r2
is this the way i am not able to understand how to write this in assembly language any one please help me
[269 byte] By [lucky123] at [2007-11-19 19:57:00]