3. Types of Processor Flashcards
Define the stored program concept
Machine code instructions are fetched and executed serially by a processor that performs arithmetic and logical operations
Where is the program that needs to be executed held according to the stored program concept?
Main memory
What happens to machine code instructions in the stored program concept?
Fetched 1 at a time, decoded and executed in the processor
What basic components are included in the Von Neumann architecture?
- ALU
- Single CU
- Registers
- Memory units
How are data and instructions stored and transferred in the Von Neumann architecture?
- Stored in the same memory
2. Transferred via the same data bus
Is the word length of all the memory the same or different?
It is the same, regardless of whether it holds data or instructions
What concept is the Von Neumann architecture built on?
The stored program concept
How are data and instructions stored in Harvard architecture?
In physically separate memories, more commonly used with embedded Digital Signal Processing (DSP) systems
When is using separate memories useful?
- When memories have different characteristics. E.g. instructions may be read-only, data may be read-write
- When optimising the size of individual memory cells and their buses. E.g. instruction memory can be designed to be larger so larger word sizes can be used for instructions
Is Von Neumann or Harvard architecture cheaper?
Von Neumann
Is Von Neumann or Harvard architecture faster and why?
Harvard: data and instructions can be fetched in parallel rather than competing for the same bus like in Von Neumann
Name 5 DSP applications
- Audio and speech signal processing
- Sonar and radar signal processing
- Biomedical signal processing
- Seismic data processing
- Digital image processing
Name 4 embedded systems
- Navigation systems
- Traffic lights
- Aircraft flight control systems
- Simulators
Does Von Neumann architecture contain large programs?
No, Harvard architecture does but Von Neumann programs can be optimised in size
Where is Von Neumann architecture used?
Conventional PCs, severs and embedded systems with only control functions
What are contemporary processors?
Processors that use a combination of Von Neumann and Harvard architecture
Describe a design of a contemporary processor
Using Von Neumann architecture when working on data and instructions in main memory
Using Harvard architecture to divide cache into instruction cache and data cache
What does RISC stand for?
Reduced Instruction Set Computer
What does CISC stand for?
Complex Instruction Set Computer
Name the main features of a RISC processor
- Small instruction set
- Each instruction is approximately 1 line of machine code
- Only takes 1 clock cycle for every instruction
Name the main features of a CISC processor
- Large instruction set
- Instructions built on the hardware
- Use as few lines of assembly code as possible
Describe the compilers in RISC and CISC processors
RISC - Compiler needs to do more work to translate high level code into machine code
CISC - Compiler does less work
Describe the RAM in RISC and CISC processors
RISC - More is required to store code
CISC - Less RAM since code is shorter
Which of RISC and CISC allows for pipelining?
RISC - Each instruction takes one clock cycle
Which of RISC and CISC uses specialised instructions?
CISC - Even though only a few of them are used
Which of RISC and CISC is the more popular processor design?
RISC
Where is CISC used?
Micro-controllers and embedded systems
What is a co-processor?
An extra processor used to supplement the functions of the primary processor
Name 3 examples of a function for a co-processor
- Performing floating point arithmetic
- Graphics processing
- Digital Signal Processing
What are multi-core CPUs able to do?
Distribute workload across multiple CPU cores, achieving significantly higher performance
How does a parallel system work?
Distributing workload using a single core by using threading
Is a multi-core or parallel system better for larger projects?
Multi-core systems perform better
