Learn: What Registers Do (Big Picture)

Welcome!You've already learned about why the CPU is essential and how the Fetch-Decode-Execute Cycle works. Now, let's explore Registers, which play a key role in helping the CPU process instructions efficiently.

What Are Registers?Registers are small, fast storage locations inside the CPU. They temporarily hold data and instructions that the CPU is actively working on. They help the CPU process tasks quickly by reducing the need to access slower memory like RAM.

Why Are Registers Important?Registers are critical for the CPU's efficiency because they store data that is needed immediately. By keeping frequently used data close to the CPU, registers help minimise delays and improve the speed of processing during the Fetch-Decode-Execute Cycle.

Types of RegistersThere are several key types of registers in the CPU, each with a specific role:Program Counter (PC): Stores the memory address of the next instruction to execute.Memory Address Register (MAR): Holds the address of the memory location to be read or written.Memory Data Register (MDR): Stores the data being transferred to or from memory.Accumulator (ACC): Stores the results of calculations performed by the CPU.

Memory Address Register (MAR) and Memory Data Register (MDR)The Memory Address Register (MAR) stores the address of the memory location being accessed. The Memory Data Register (MDR) temporarily holds the data being read from or written to memory.These two registers work together during the Fetch-Decode-Execute Cycle to ensure instructions and data are moved between the CPU and memory efficiently.

Accumulator (ACC)The Accumulator is another important register in the CPU. It stores the results of calculations and operations performed by the Arithmetic Logic Unit (ALU). For example, if the CPU adds two numbers, the result is stored in the Accumulator.

Review Time!Great work! You've learned about the key registers in the CPU and their roles. Let's test your understanding with a few questions.