Bit Position Indicator

The Bit Position Indicator is the period. This generally appears in "Flag Affected" fields of bit-breakdown diagrams, meaning that that specific bit is unaffected. It is a placeholder meant to take up space, and is distinct from a question mark or space character, which in reverse engineering indicate "don't know what happens to this bit."

The official SPC700 documentation is missing some periods to indicate the carry flag is not affected.

Reference

• Appendix C-1 of Book I of the official Super Nintendo development manual