MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor Glossary-9
Supervisor mode. The privileged operation state of a processor. In supervisor mode,
software, typically the operating system, can access all control registers and can
access the supervisor memory space, among other privileged operations.
Synchronization. A process to ensure that operations occur strictly in order. See Context
synchronization and Execution synchronization.
Synchronous exce ption. An exception that is generated by the execution of a particular
instruction or instruction sequence. There are two types of synchronous
exceptions, precise and imprecise.
System memory. The physical memory available to a processor.
TTime-division multiplex (TDM). A single serial channel used by several channels taking
turns.
TLB (translation lookaside buffer) A cache that holds recently-used page table entries.
Throughput. The measure of the number of instructions that are processed per clock cycle.
UUISA (user instruction set architecture). The level of the architecture to which user-level
software should conform. The UISA defines the base user-level instruction set,
user-level registers, data types, floating-point memory conventions and exception
model as seen by user programs, and the memory and programming models.
User mode. The unprivileged operating state of a processor used typically by application
software. In user mode, software can only access certain control registers and can
access only user memory space. No privileged operations can be performed. Also
referred to as problem state.
VVEA (virtual environment architecture). The level of the architecture that describes the
memory model for an environment in which multiple devices can access memory,
defines aspects of the cache model, defines cache control instructions, and defines
the time-base facility from a user-level perspective. Implementations that conform
to the PowerPC VEA also adhere to the UISA, but may not necessarily adhere to
the OEA.
Virtual address. An intermediate address used in the translation of an effective address to
a physical address.
Virtua l memor y. The address space created using the memory management facilities of
the processor. Program access to virtual memory is possible only when it
coincides with physical memory.
WWatchpoint. An event that is reported, but does not change the timing of the machine.
Word. A 32-bit data element. Note that on other processors a word may be a different size.