O que é Field-programmable gate array, configurable logic block?

A field-programmable gate array (FPGA) is a chip whose logic and wiring are configured after manufacture by loading a configuration file: an array of small programmable logic elements, memories, arithmetic blocks and serial transceivers, joined by programmable routing. A configurable logic block is the array’s repeated logic element: a group of lookup tables, each of which computes any Boolean function of a few inputs by looking it up in a small memory, with flip-flops to register their outputs and a carry chain for arithmetic.