register

n 1: an official written record of names or events or

transactions [syn: {registry}]

2: the timbre characteristic of a certain range and manner of

production of the human voice

3: a book in which names and transactions are listed

4: an arrangement (usually in the floor or a wall of a room)

for admitting or excluding heated air from the room

5: a device (as a sliding plate) for regulating the flow of air

into a furnace or other heating device

6: a cashbox with an adding machine to register transactions;

used in shops to add up the bill [syn: {cash register}]

v 1: record in writing; enter into a register

2: register in a public office or in a court of law; "file for

divorce"; "file a complaint" [syn: {file}]

3: register to vote; "register for an election"

4: be aware of [syn: {record}]

5: indicate a certain reading; of gauges and instruments; "The

thermometer showed thirteen degrees below zero"; "The

gauge read `empty'" [syn: {read}, {show}, {record}]

6: register as a candidate for several parties [syn: {cross-file}]

7: show in one's face; "Her surprise did not register"

8: send by registered mail; "I'd like to register this letter"

9: enter into someone's consciousness

register

1. One of a small number of high-speed memory locations in a

computer's {CPU}. Registers differ from ordinary

{random access memory} in several respects:

There are only a small number of registers (the "register

set"), typically 32 in a modern processor though some,

e.g. {SPARC}, have as many as 144. A register may be directly

addressed with a few bits. In contrast, there are usually

millions of words of main memory (RAM), requiring at least

twenty bits to specify a memory location. Main memory

locations are often specified indirectly, using an {indirect

addressing} mode where the actual memory address is held in a

register.

Registers are fast; typically, two registers can be read and a

third written -- all in a single cycle. Memory is slower; a

single access can require several cycles.

The limited size and high speed of the register set makes it

one of the critical resources in most computer architectures.

{Register allocation}, typically one phase of the {back-end},

controls the use of registers by a compiled program.

See also {accumulator}, {FUBAR}, {orthogonal}, {register

dancing}, {register allocation}, {register spilling}.

2. An addressable location in a {memory-mapped} peripheral

device. E.g. the transmit data register in a {UART}.