MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor Glossary-7
Physical memory. The actual memory that can be accessed through the system’s memory
bus.
Pipelining. A technique that breaks operations, such as instruction processing or bus
transactions, into smaller distinct stages or tenures (respectively) so that a
subsequent operation can begin before the previous one has completed.
Precise exceptions. A category of exception for which the pipeline can be stopped so
instructions that preceded the faulting instruction can complete, and subsequent
instructions can be flushed and redispatched after exception handling has
completed. See Imprecise exceptions.
Primary opcode. The most-significant 6 bits (bits 0–5) of the instruction encoding that
identifies the type of instruction. See Secondary opcode.
Protection boundary. A boundary between protection domains.
Protection domain. A protection domain is a segment, a virtual page, a BAT area, or a
range of unmapped effective addresses. It is defined only when the appropriate
relocate bit in the MSR (IR or DR) is 1.
QQuad word. A group of 16 contiguous locations starting at an address divisible by 16.
RrA. The rA instruction field is used to specify a GPR to be used as a source or destination.
rB. The rB instruction field is used to specify a GPR to be used as a source.
rD. The rD instruction field is used to specify a GPR to be used as a destination.
rS. The rS instruction field is used to specify a GPR to be used as a source.
Real address mode. An MMU mode when no address translation is performed and the
effective address specified is the same as the physical address. The processor’s
MMU is operating in real address mode if its ability to perform address translation
has been disabled through the MSR registers IR and/or DR bits.
Record bit. Bit 31 (or the Rc bit) in the instruction encoding. When it is set, updates the
condition register (CR) to reflect the result of the operation.
Register indirect addressing. A form of addressing that specifies one GPR that contains
the address for the load or store.
Register indirect with immediate index addressing. A form of addressing that specifies
an immediate value to be added to the contents of a specified GPR to form the
target address for the load or store.
Register indirect with index addressing. A form of addressing that specifies that the
contents of two GPRs be added together to yield the target address for the load or
store.