The IDT7381 and IDT7383 are high-speed cascadable Arithmetic Logic Unit (ALUs). Both three-bus devices have two input registers, ultra-fast 16-bit ALUs and 16-bit output registers. With IDT's high-performance CMOS technology, the IDT7381/7383 can do arithmetic or logic operations in 20ns. The IDT7381 functionally replaces four 54/74S381 fourbit ALUs in a 68-pin package. The two input operands, A and B, can be clocked or fed through for flexible pipelining. The F output can also be set into clocked or flow-through mode. An output enable is provided for three-state control of the output port on a bus. The IDT7381 has three function pins to select 1 of 8 arithmetic or logic operations. The two R and S selection pins determine whether A, B, F or 0 are fed into the ALU. This ALU has carry-out, propagate and generate outputs for cascading using carry look-ahead.