Soft core (synthesis)

A soft core (also called softcore) is a digital circuit that can be wholly implemented using logic synthesis. It can be implemented via different semiconductor devices containing programmable logic (e.g., ASIC, FPGA, CPLD), including both high-end and commodity variations. Many soft cores may be implemented in one FPGA.
In those multi-core systems, rarely used resources can be shared between all the cores.
Examples of soft core implementations are soft microprocessors, graphics chips like AGA or Open Graphics Project, harddisc controllers etc.