The 2200 design allowed 8-bit registers H and L (High and Low) to be paired into a 16-bit address register HL. In the 8080, this pairing was added to the BC and DE pairs as well, while HL was generalized to allow use as a 16-bit accumulator, not just an address register. The 8080 also introduced the important 8-bit immediate data mode for accumulator operations, and immediate 16-bit data for HL, BC and DE loads. Furthermore, direct 16-bit copying between HL and memory was now possible, using a direct address.