Learn: Data vs Address - Telling Them Apart in Registers

Welcome!Welcome back! So far, you've explored how the CPU works, including the roles of registers like the MAR (Memory Address Register) and MDR (Memory Data Register). Today, we'll focus on understanding the difference between data and addresses in registers. This is key to grasping how instructions and memory work together in the CPU!

What Is the Difference Between Data and Address?In computing, data refers to the actual information or values being processed, such as a number or text. An address is a specific location in memory where data or instructions are stored. These two are closely linked but serve very different purposes in the CPU.

Memory Address Register (MAR)The MAR holds the address of the memory location that the CPU needs to access. This could be the address of data to be read or written, or the address of the next instruction to execute.

Memory Data Register (MDR)The MDR holds the data that is being transferred to or from memory. For example, if the CPU reads a value from memory, it temporarily stores that value in the MDR before processing it.

How Do MAR and MDR Work Together?These two registers work closely during the fetch-decode-execute cycle. The MAR identifies where the CPU should look in memory, while the MDR temporarily holds the data being read or written. This ensures the CPU always knows what data to process and where to find it.

Data vs Address: Key DifferencesTo summarise:Data is the information or values being processed, such as numbers or text.Addresses are memory locations where data or instructions are stored.The MAR stores addresses, while the MDR stores data.

Review Time!Great job! You've learned about how data and addresses are handled in registers. Let's test your understanding with a few questions.

Well Done!You've mastered the difference between data and addresses in registers. This understanding is essential for working with CPU memory systems. Keep practising, and great work today!