/ Shows a dumb but simple way of getting input
/ via the Switch Register (SR). This program
/ saves the initial value of the SR, then halts
/ to wait for the user to enter a new value in
/ the SR, then adds the new SR value to the old
/ SR and leaves the result in the AC.
*0200
START,  CLA OSR
        DCA SAVE
        HLT
        CLA OSR
        TAD SAVE
        HLT

SAVE,   0000