What does SHFTR stand for?

Shift Register

Two or more bistable elements connected in series. With each tick of the clock, the output of stage n is shifted to stage n+1. Applications include clock or signal delays, delay lines, linear-feedback shift registers. A digital circuit capable of storing and shifting binary data. Shift register A circuit in which all bits are shifted one position at each clock cycle. It can be either linear or it can be cyclic or looped.