The Memory Address Register (MAR) is an important register in computer processing that acts as a temporary storage unit for memory addresses. This register is responsible for storing the memory address from which data is fetched into the CPU registers, or to which data is sent and stored via the system bus.
The role of the MAR is to access data and instructions from memory during the execution phase of an instruction. By storing the location of the data that needs to be accessed, the MAR ensures that the correct data is retrieved for the CPU to process.
When reading from memory, the data addressed by MAR is entered into the Memory Data Register (MDR) and then used by the CPU. Similarly, when writing to memory, the CPU writes data from the MDR to the memory location whose address is stored in MAR.
Address registers are designed to enable indexing into an array of constant registers. This means that address registers allow you to enter a signed integer offset into the constant registers. These registers can only be written to with the mov command, and are read-only. Hence, they can only be used for indexing into the array of constant registers and not for any other purpose.
The number of bits in the register determines the size of the addressable memory. A high-speed circuit in a computing device contains the addresses of the data to be processed or the next instruction to be executed. Understanding the function of the MAR is essential for programming, encoding, and debugging.
FAQs
What is the Memory Address Register (MAR)?
The Memory Address Register (MAR) is a CPU register that temporarily stores the memory address from which data is fetched into the CPU registers, or to which data is sent and stored via the system bus.
What is the role of the MAR in computer processing?
The role of the MAR is to access data and instructions from memory during the execution phase of an instruction. By storing the location of the data that needs to be accessed, the MAR ensures that the correct data is retrieved for the CPU to process.
What is the relationship between the MAR and MDR?
When reading from memory, the data addressed by MAR is entered into the Memory Data Register (MDR) and then used by the CPU. Similarly, when writing to memory, the CPU writes data from the MDR to the memory location whose address is stored in MAR.
Conclusion
The Memory Address Register (MAR) plays a crucial role in computer processing by accessing data and instructions from memory during execution. Its function as a storage unit for memory addresses ensures that the CPU retrieves the correct data for processing. Programmers, developers, and computer enthusiasts can benefit from understanding how MAR is used in computer processing.
