A register is a computer memory built directly into the processor or CPU (Central Processing Unit). It is used to store and manipulate data during the execution of instructions. Registers may hold an instruction, a storage address or any kind of data. The information stored in a register can be retrieved quickly and easily. It improves computer performance by speeding up processes. It is also used in embedded systems, which are self-contained computer systems found in devices such as cars and household appliances.
A register consists of a group of flip-flops and gates that control how the bits within it are saved and processed. Each flip-flop is capable of saving one bit of binary information – either a 0 or a 1. Registers are designed to be economical in size and operation, so they typically contain fewer flip-flops than the number of bits that they are expected to process.
There are a variety of types of registers in modern computers. Some are user accessible, which means that running software can specify what values to put in them, while others are not user accessible and cannot be changed by software. The program counter and instruction register are examples of special purpose registers.
The instruction register contains the machine instructions that have been fetched from main memory. It is decoded by the CPU to determine what operation it will perform on the data in the register, and it is the location where the results of the arithmetic and logical operations are stored. The accumulator register is another general-purpose register, which stores initial data that will be used as well as the intermediate and final results of each operation.
Besides the storage capacity of a register, it can also contain control logic circuitry that facilitates its functions like data transfer and manipulation. This makes it a highly efficient and powerful part of the CPU.
Registers are commonly used in financial transactions. A register of shareholders, for example, keeps a record of each person who owns shares in a public company. It also includes their names, addresses and the number of shares they own. The list is updated regularly as new shareholders purchase or sell their stock. Companies must keep such records to meet regulatory requirements and to comply with laws and regulations, including filing a report with the Securities and Exchange Commission.
There is also a register of debts, which is a database of outstanding loans by a bank or other financial institution. The system combines a database with an internal register to track when the loan will become due for repayment. A similar database is a maturity ticker, which shows the current date that a loan will expire and lists the maturities in chronological order.
A register can be a useful tool in the development of software. It can help developers test programs without having to load them into the actual hardware. It can also be used to document changes in the source code of an application so that other developers can see what has been changed and how it was done.