Advances the blinking selector by writing attribute $46 into cell $5967+offset ($C596 holds the 0-19 offset within this row). While the advanced offset is still < 20 ($14), that is the whole effect for this call: save offset+1 back to $C596 and return via $C19B. Once the offset would wrap past 20, the selector has completed a full pass along this row: additionally nudge the row pointer held at $C597 -- clear its old highlighted cell (attribute $42), move it on by one screen line (+$20) then step it back by 31 (net +1 down and +1 right, i.e. onto the next row's first cell, attribute $02) -- and if that pointer's low byte has itself reached $17 (23), the whole multi-row cycle is complete and control passes to nei_finalise (name entry finished/row exhausted) instead of resetting the offset to 0 and continuing. $C596 and $C597 start at 0 and $590A respectively (from the 13-byte template at $C580, copied by check_high_score). $C597's low byte must climb from $0A to $17, i.e. 13 row-wraps of 20 cells at 12 frames/cell = 3120 frames (~62s at 50Hz) of elapsed time with no player input before this idle path alone forces nei_finalise, independent of RIGHT/LEFT/FIRE.

Redraw the cursor cells one final time ($C23E-$C251), mirroring $C172-$C18D above.