An encoder that supports multiple code rates and code lengths is disclosed. A shift register utilized by the encoder may be scaled in size based on a selected code rate or code length. The shift register shifts a bit series for the matrix without requiring fixed feedback points within the register. The sizes of the matrix and bit series are based on the selected code rate or code length, and the encoder loads the bit series into a first portion of the shift register, and a division of the bit series into a second portion of the shift register located adjacent to the first portion. The encoder periodically repopulates the shift register from memory to simulate circular shifting of the bit series without feedback points. Accordingly, complexity of the encoder is reduced.