MPC885 PowerQUICC Family Reference Manual, Rev. 2
Glossary-6
Freescale Semiconductor
Most-significant byte (MSB). The highest-order byte in an address, registers, data
element, or instruction encoding.
N
No-op. No-operation. A single-cycle operation that does not affect registers or generate
bus activity.
O
OEA (operating environment architecture). The level of the architecture that describes
the memory management model, supervisor-level registers, synchronization
requirements, and the exception model. It also defines the time-base feature from
a supervisor-level perspective. Implementations that conform to the PowerPC
OEA also conform to the PowerPC UISA and VEA.
Optional. A feature, such as an instruction, a register, or an exception, that is defined by
the PowerPC architecture but not required to be implemented.
Out-of-order. An aspect of an operation that allows it to be performed ahead of one that
may have preceded it in the sequential model, for example, speculative operations.
An operation is said to be performed out-of-order if, at the time that it is
performed, it is not known to be required by the sequential execution model. See
In-order.
Out-of-order execution. A technique that allows instructions to be issued and completed
in an order that differs from their sequence in the instruction stream.
Overflow. An error condition that occurs during arithmetic operations when the result
cannot be stored accurately in the destination register(s). For example, if two
32-bit numbers are multiplied, the result may not be representable in 32 bits.
P
Pace control. Controls the rate of the data flow between a master and slave.
Page. A region in memory. The OEA defines a page as a 4-Kbyte area of memory, aligned
on a 4-Kbyte boundary.
Page fault. A page fault is a condition that occurs when the processor attempts to access a
memory location that does not reside within a page not currently resident in
physical memory. On MPC8xx processors, a page fault exception condition occurs
when a matching, valid page table entry (PTE[V] = 1) cannot be located.
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.
Summary of Contents for PowerQUICC MPC870
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Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
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Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...