High-precision division and square root
Alan H. Karp, Peter W. Markstein · ACM Transactions on Mathematical Software · 1997
We present division and square root algorithm for calculations with more bits than are handled by the floating-point hardware. These algorithms avoid the need to multiply two high-precision numbers, speeding up the last iteration by as much as a factor of 10. We also show how to produce the floating-point number closest to the exact result with relatively few additional operations.