In computer science, register is an important type of memory that stores data and instructions for rapid processing. They are essential to the functioning of CPUs (central processor units) and embedded systems, which are small computer components that can be found in devices like cars or household appliances.
To register something means to place it on an official list of people or things that can be accessed by others. Examples include registers of births and deaths, school enrollment lists, and the names of candidates for office. Registries are also used to track medical procedures and medication. In business, a register can be a database of customers and their contact information that can be accessed by salespeople to follow up with prospects.
The term register can also refer to a specific kind of writing, such as a legal document or an account book. In the case of legal documents, a register may contain details of contracts, invoices, and other financial transactions. In the case of accounts, it may record transactions from bank accounts and credit cards. In the United States, there are several types of registers: the Public Records Act requires that certain kinds of documents be filed with a government agency, such as the county clerk or the state archives. Publicly traded companies are required to file their financial reports with the Securities and Exchange Commission.
A register can also refer to a set of rules for the use of a language, such as a grammar book or style guide. For example, in English, a formal register might encourage speakers to pronounce words with the velar nasal rather than the alveolar nasal, and to avoid using nonstandard words such as y’all or ain’t.
Computer registers are an important component of a CPU because they are the fastest kind of memory available to a processor. They can store the instructions that are currently being processed and they can hold intermediate results from calculations, which allows them to speed up processes by avoiding the delay of retrieving the values from main memory. They are also often the location where a CPU will write its results to screen or to other peripheral devices.
Registers are made up of flip-flops and gates that control when and how new data is added to them. They are usually grouped together into larger structures called register files. A single register can store a large amount of data, but the most common kind of register file is one that contains 64 registers. Most of these registers are user accessible, but a smaller number are internal and cannot be addressed by software. Those internal registers are often referred to as flag registers.