CPU Flashcards
CPU
Processes data and instructions. The instructions consist of:
- Simple arithmetic
- Logical operations
Controller
Sends and receives signals from all parts of the computer. It ensures that all processes take place at the right time and in the correct order
ALU
The part of the CPU that processes and manipulates data. It performs simple calculations and comparison on the data that is temporarily stored in the registers.
Registers
A storage location found on the CPU where data or control information is temporarily stored. Registers are usually much faster to access than internal memory.
Internal memory
Fast access temporary storage on the CPU. Data is moved from the registers to the internal memory when it is not actively being used.
Buses
Allow data to be transferred to different parts of the computer. There are three main Buses used by the GPU:
- Address bus
- Data bus
- Control bus
Address bus
When data is saved or loaded from memory, the address at which it is to be stored or loaded from must be sent. The storage address of the data always travels along the address bus.
Data bus
Data will then need to be moved between several parts of the computer. The path along which data travels is called the data bus.
Control bus
The controller uses the control bus to send control signals to different parts of the computer
Von Neumann
The program and the data is stored in the same memory space. Easier to re-program. This means an instruction fetch and a data operation cannot occur at the same time as they share a common bus (Von Neumann bottleneck)
Program counter
Stores the memory location of the next instruction that will be needed by the processor.
Current instruction register
Stores the instruction that is currently being executed by the processor
Accumulator
Stores the results of calculations made by the ALU
Memory address register
Stores the memory locations where data is currently being written to or read from
Memory data register
Stores the data that is being transferred from memory to the CPU (or vice versa)
Input Device
Allows data, such as text, images, video or sound, to be entered into a computer system.
Output Device
Allows data, such as text, images, video or sound, to be come out of a computer system.
Fetch
Takes the address required from memory, stores it in the instruction register, and moves the program counter on one so that it points at the next instruction
Decode
The control unit checks the instruction in the instruction register. The instruction is decoded to determine the action that needs to be carried out.
Execute
The actual actions that happen during the execution cycle depend on the instruction itself
Amount of cache memory
Cache memory improves the performance of the CPU as it is able to provide instructions and data to the CPU at a much faster rate than other system memory such as RAM. The more your system has, the better its performance.
Clock Speed
The faster the clock speed, the faster the computer is able to run the fetch-decode-execute cycle and therefore process more instructions
Number of Cores
Multi-core processors have many processing components within the same CPU. In a single-core CPU each instruction is processed one after the other, whereas in a dual core CPU, two instructions may be processes at the same time. In theory, a dual-core CPU should be able to process instructions twice as fast as a single-core CPU.
