Shared Recurrence Floating-Point Divide/Sqrt and Integer Divide/Remainder With Early Termination

Kevin Kim, Katherine Parry, David M. Harris, Cedar Turek, Alessandro Maiuolo, Rose Thompson, James E. Stine

Abstract: Division, square root, and remainder are fundamental operations required by most computer systems. Floating-point and integer operations are commonly performed on separate datapaths. This paper presents the first detailed implementation of a shared recurrence unit that supports floating-point division/square root and integer division/remainder. It supports early termination and shares the normalization shifter needed for integer and subnormal inputs. Synthesis results show that shared double-precision dividers producing at least 4 bits per cycle are 9 - 18% smaller and 3 - 16% faster than separate integer and floating-point units.