Meta Platforms, Inc.
Circuit and method for calculating non-linear functions of floating-point numbers

Abstract:

A circuit and method for calculating a non-linear function of floating-point numbers using hierarchical look-up tables are provided. The look-up tables are programmable to hold non-linear ranges of values for any of a variety of non-linear functions. The circuit includes computation modules in respective stages of a high-throughput computation pipeline. A first computation module in a first stage receives one or more floating-point numbers and, for each floating-point number, selects a first entry from a first look-up table based on the floating-point number. The first computation module then calculates and outputs a table index and a variable based on the first floating-point number and the first entry. The second compute module in a second stage, selects a second entry from a second look-up table based on the table index, and calculates and outputs an approximate value for the non-linear function using the variable and the second entry.