Unified Digit Selection for Radix-4 Recurrence Division and Square Root

Division and square root are fundamental operations required by most computer systems. They are commonly implemented in hardware using radix-4 recurrence, which produces a 2-bit result digit on each step. Unified digit selection logic chooses the next quotient or square root digit based on a residual and divisor or square root approximation. This paper presents the first derivation of digit selection constants for unified radix-4 recurrence division and square root.