I am at a big question of what in the world this program is useful for. You are polling the port bit
state at intervals that are at least as long as your DELLAY routine but also variable in period by the various path times through your code as you go around the loop. It seems to me that this method does not gather any particularly intellegent data from the port pin!! If you were actually trying to gather some type of intellegent data flow through the port pin would you not be trying to decypher some type of modulation format coming in from the port pin OR maybe use another port pin as a handshaking or CLK pin to indicate when data on the input pin is valid??

Michael Karas