The MIPS64 and microMIPS64 Privileged Resource Architecture (PRA) is a set of environments and capabilities on
which the Instruction Set Architectures operate. The effects of some components of the PRA are user-visible, for
instance, the virtual memory layout. Many other components are visible only to the operating system kernel and
systems programmers. The PRA provides the mechanisms necessary to manage the resources of the CPU: virtual
memory, caches, exceptions and user contexts. This chapter describes these mechanisms.