Chapter 5 Processor fundamentals Flashcards
What are the basic features of the Von Neumann model of a computer?
- There is a processor, a central processing unit.
- The processor has direct access to a memory
- The memory contains a stored program that is being executed.
- The stored program consists of individual instructions
- The processor executes instructions sequentially
Which are the main components of a CPU and what do they do?
- The ALU is the Arithmetic and logic circuit and it is responsible for any arithmetic or logic processing that might be needed when a program is running.
- The control unit that does the following:
- Controls the flow of data through the processor and computer
- Ensures that computer data is handled correctly
Which are the two most important parts of the control unit and why?
The internal clock - controls the cycles inside the processor and its frequency is called clock speed
The system clock - controls the activities outside the processor
What are registers, where are they situated and how much can they store?
The registers are storage components very close to the ALU and can store 16, 32 or 64 bits.
What are the general purpose registers?
A general purpose register or an accumulator can store only a single value at a given time.
What is an accumulator?
An accumulator is a general purpose register that stores a value or instruction before and after the execution of an instruction by the ALU
How does the ALU use accumulators?
The ALU uses accumulators to store instructions in them that can be changed to other instructions.
Which are the special purpose registers and what do they do?
CIR (Current Instruction Register) - store current instruction while executed
PC (Program Counter) - stores the address of where the next instruction is to be read from.
IX (Index register) - Stores a value for indexed addressing
MAR (Memory Address Register) - Stores the address where the CPU is going to read from or write to a value
MDR (Memory Data Register) - stores data that was read from a memory or is about to be written into a memory because it is closer to the processor.
SR (Status Register) - operates as a flag so it will signal certain errors or situations
What is a system bus?
A system bus is a parallel transmission component with each separate wire carrying a single bit.
What is crucial to remember about a system bus?
A system bus isn’t a storage device.
What does a system bus consist of?
Address bus
Data bus
Control bus
What is an address bus do?
The address bus is a component that carries an address to the memory controller from the MAR to identify and address where data is to be read from or written to.
What can identify how many addresses an address bus can carry?
The number of wires is defining how many addresses an address bus can carry.
What kind of bus is an address bus?
An address bus is a one way bus.
What does a data bus do?
Carries data to and from the processor