Registers are part of the central processing unit (CPU) of a computer. Registers are memory locations that can be accessed quickly for rapid retrieval of data.
Most processors have multiple registers, called a register array, that hold data and instructions that must be accessed rapidly during the execution of an application.
One of the registers located in the computer's processor is the memory address register or MAR. The MAR stores the physical memory address where the next piece of data will be written or the next instruction is located.
The MAR is also known as a Memory Address Translator or Decoder. This is because it translates the data to the read from memory or written to memory into an actual location on the memory, assigning the space on RAM to be used by the CPU.
During the process of fetching data and executing applications, the CPU uses the MAR to store the address to which these data will be placed on the system RAM, or where they will be accessed from.