Glossary
A-3
Glossary
L
latency:
The delay between when a condition occurs and when the device
reacts to the condition. Also, in a pipeline, the necessary delay between
the execution of two instructions to ensure that the values used by the
second instruction are correct.
LSB:
least significant bit. The lowest-order bit in a word.
M
maskable interrupt:
A hardware interrupt that can be enabled or disabled
through software.
memory stall:
When the CPU is waiting for a memory load or store to finish.
MSB:
most significant bit. The highest-order bit in a word.
N
nested interrupt:
A higher-priority interrupt that must be serviced before
completion of the current interrupt service routine.
nonmaskable interrupt:
An interrupt that can be neither masked nor manu-
ally disabled.
O
overflow:
A condition in which the result of an arithmetic operation exceeds
the capacity of the register used to hold that result.
P
pipeline:
A method of executing instructions in an assembly-line fashion.
program memory:
A memory region used for storing and executing programs.
R
register:
A group of bits used for holding data or for controlling or specifying
the status of a device.
reset:
A means of bringing the CPU to a known state by setting the registers
and control bits to predetermined values and signaling execution to start
at a specified address.
Glossary