Code:
testnumber var word
main:
if testnumber = 0 then
    lcdout "Undefined"
    stop
endif
testnumber = testnumber - 1
testnumber = testnumber - 1
if testnumber = 0 then
     lcdout "EVEN"
     stop
endif
if testnumber = $ffff then
     lcdout "ODD"
     stop
endif
if testnumber > 0 and testnumber < $ffff then lcdout "Not done yet"
goto main
end
Should work, haven't tried it...but it's surely a waste of resources!