AMD Generic Encapsulated Software Architecture (AGESA), is a bootstrap protocol by which system devices on AMD64-architecture mainboards are initialized. The AGESA software in the BIOS of such mainboards is responsible for the initialization of the processor cores, memory, and the HyperTransport controller.
AGESA documentation was previously available only to AMD partners that had signed a non-disclosure agreement (NDA). AGESA source code was open-sourced in early 2011 to gain track in coreboot.
AGESA is linked to AMD PowerTune.
References
AGESA Wikipedia(Text) CC BY-SA