CPU Registers
CPU Registers
» Registers are high-speed storage areas within the CPU, but have the least storage capacity. Registers are not referenced by their address, but are directly accessed and manipulated by the CPU during instruction execution.
» Registers store data, instructions, addresses and intermediate results of processing. Registers are often referred to as the CPU’s working memory.
» The data and instructions that require processing must be brought in the registers of CPU before they can be processed. For example, if two numbers are to be added, both numbers are brought in the registers, added and the result is also placed in a register.
» Registers are used for different purposes, with each register serving a specific purpose.
Some of the important registers in CPU are as follows —
• Accumulator (ACC) stores the result of arithmetic and logic operations.
• Instruction Register (IR) contains the current instruction most recently fetched.
• Program Counter (PC) contains the address of next instruction to be processed.
• Memory Address Register (MAR) contains the address of next location in the memory to be accessed.
• Memory Buffer Register (MBR) temporarily stores data from memory or the data to be sent to memory.
• Data Register (DR) stores the operands and any other data.