CPU registers

Start with the register names

The CPU registers mind map is a starting point for this topic. It brings together the Memory Address Register (MAR), Memory Data Register (MDR), Current Instruction Register (CIR), Program Counter (PC) and Accumulator (ACC). Use it to get familiar with the names and abbreviations before moving on to their roles.

The Registers mind map also brings together register abbreviations with the control unit and arithmetic logic unit. Comparing the two maps can help you see which terms you recognize and which you need to look at again.

Practice with flashcards and quizzes

After looking at a map, move to the flashcard deck titled Registers. Its cards cover the program counter, MAR, MDR and accumulator, as well as the sequence of events in the CPU. The deck titled registers asks what several abbreviations stand for and what those registers do.

For another way to practice, try the flashcards on CPU registers and buses. They ask about the buses in the CPU and the jobs of the program counter and accumulator. The Registers and busses deck also includes register terms and types of bus.

Registers Quiz is another option for checking your knowledge after using the maps and cards. Return to a mind map when a term needs another look, then use the flashcards to practice recalling it without the map in front of you.

Explore the wider unit

CPU registers is one section of Computer Architecture and the CPU, within Computing and ICT (programming, computer science, digital skills, educational technology). On this page, the Inside the processor mind map places registers within the CPU and includes the program counter. Hardware & Data transmission covers central computer components and includes fetch, execute and decode.

Use these broader maps after the register-focused resources to see the terms in a wider processor context. Choose a resource and follow the terms that you want to practice.