9618 · 4.1
Central Processing Unit (CPU) Architecture flashcards
Revision flashcards for Cambridge 9618 Central Processing Unit (CPU) Architecture (syllabus 4.1). Flip, recall, then mark a real past-paper question.
Card
What is the Von Neumann architecture?
A computer architecture where program instructions and data are stored in the same memory and share the same data bus for transfer.
Card
What is the 'stored program concept'?
The principle that program instructions can be stored in main memory, just like data. This allows programs to be loaded, run, and even modified by the computer itself.
Card
What is the role of the Arithmetic and Logic Unit (ALU)?
The part of the CPU that performs all arithmetic calculations (e.g., addition, subtraction) and logical operations (e.g., AND, OR, NOT).
Card
What is the role of the Control Unit (CU)?
The CU manages and coordinates the activities of the CPU. It decodes instructions and sends control signals to other components to execute them.
Card
What is a register?
A small, extremely fast, temporary storage location located directly within the CPU.
Card
What does the Program Counter (PC) hold?
The memory address of the *next* instruction to be fetched from main memory. It is automatically incremented after each fetch.
Card
What is the purpose of the Memory Address Register (MAR)?
To hold the address in main memory that is currently being read from or written to. It receives an address from the PC or the instruction itself.
Card
What is the purpose of the Memory Data Register (MDR)?
A bidirectional register that temporarily holds data or instructions being transferred between the CPU and main memory.
Card
What does the Current Instruction Register (CIR) hold?
The instruction that has just been fetched from memory and is currently being decoded and executed.
Card
What is the Accumulator (ACC)?
A general-purpose register used to temporarily store the results of calculations from the ALU.
Card
What are the three buses in the system bus?
1. Address Bus (carries memory addresses from CPU to memory). 2. Data Bus (carries data/instructions between CPU and memory). 3. Control Bus (carries control signals and clock pulses).
Card
How does clock speed affect CPU performance?
Clock speed determines the rate at which a CPU can execute instructions (cycles per second). A higher clock speed means more Fetch-Decode-Execute cycles can be completed per second, leading to faster processing.