Abstract: A millicode method for packing the hexadecimal digits from a plurality of bytes in each of two millicode registers (R1,R1) into one of the two millicode registers extracts the rightmost hexadecimal digit from each of a plurality of bytes stored in millicode register R1 and the rightmost hexadecimal digit from each of a plurality of bytes stored in millicode register R2 and stores hexadecimal digits from said extracting step in millicode register R1 with each hexadecimal digit extracted from a byte in register R1 and from a byte in register R2 stored in millicode register R1 in register R1 positions occupied by said plurality of bytes stored in register R1 prior to said extraction step.