Using AIS allows native access to the Centaur Technology-designed RISC core inside the processor.
[5] In 2007 a patent named some microcode instructions as load and store to/from main RAM, and loadPRAM and storePRAM to/from private-RAM inside the processor.
[7] A 2002 programming reference for the Alternate Instruction set[8] and an accompanying appnote[1] were added to the Bitsavers archive in May 2021.
[9] The Microsoft Windows NT kernel KiGetFeatureBits() initialisation function proactively disables Alternate Instruction mode on boot up.
[5] Domas had partially reverse engineered the AIS instruction set using automated fuzzing against a cluster of seven thin clients.