Processor Flashcards
What is Reduced Instruction Set Computer (RISC)?
RISC has a small number of essential instructions built-in that are completed in one clock cycle. It puts an emphasis on software/compiler, giving it efficient register usage. Transistors used for CPU registers. Far less focus on decoding/executing.
What is Complex Instruction Set Computer (CISC)?
CISC has a large instruction set built into it. It puts an emphasis on hardware, making it easier to program. It uses several clocks per instruction. Transistors used for executing complex instructions, so fewer registers. Focuses decoding/executing.
Compare CISC and RISC
RISC processors have a library of simple and efficient instructions, whereas CISC processors have a large library of complex instructions made up of simpler ones. A RISC processor has few addressing modes, whereas a CISC processor has many addressing modes. CISC processors are more expensive.
What are ‘Addressing Modes’?
The Addressing Mode specifies a rule for interpreting or modifying the address field of an instruction before an operand is referenced.
What is the Processor?
The Processor is the part of a computer that handles instructions. It must be able to fetch, decode and execute instructions from RAM, perform arithmetic calculations, perform logical operations and control read, write, clock, interrupt and reset lines.
What does a Processor consist of?
The Arithmetic and Logic Unit, Registers, the Control Unit and RAM
What are Registers?
Temporary storage locations within the processor. It stores addresses, data or instructions.
What is the Control Unit?
The Control Unit manages the clock, read, write, reset and interrupt lines. It has a clock line that sends out a signal to synchronise the fetch/execute cycle. Measured in Hertz (Hz), Clock speed is a good indication of how quickly the processor can complete tasks.
What is the Arithmetic and Logic Unit? (ALU)
The Arithmetic and Logic Unit (ALU) handles all calculations and logical decisions. Does calculations, comparisons on numeric values, and makes decisions based on Logic (AND, OR, NOT).
What is an Interrupt Service Routine (ISR)?
This is code that handles what to do when an interrupt of a code/type is received by the CPU. It is a small program that deals with the request.
What is pipelining?
It is the process of storing and prioritising instructions that the processor executes.
