On the 15th of September at OpenPOWER Summit 2020, IBM announced its A2O POWER core (that’s a capital “o”, not a zero), joining the A2I core it announced on the 30th of June. These are provided as VHDL source files. The GitHub repositories and announcements are here:
The A2O core is an out-of-order, multi-threaded, 64-bit POWER ISA core that has been optimised for single-thread performance.
The A2I core is an in-order multi-threaded 64-bit POWER ISA core that has been optimised for high data throughput.