1.1.2 Types of Processor

1.1.2 Types of Processor

1. CISC (Complex Instruction Set Computer)

   • More complicated processor design
   • Uses complex instructions
   • Each instruction may take multiple machine cycles
   • Does not allow pipelining
   • Longer instruction set
   • Very little work to translate a high-level language into machine code
   • Many specialised instructions have to be built into the hardware even thoguh only about 20% of them are used in the average program
   • Integrated circuitry is more expensive
   • Requires less RAM

2. RISC (Reduced Instruction Set Computer)

   • Simpler processor design
   • Uses simpler instructions
   • Each instruction takes one machine cycle
   • Allows pipelining
   • Smaller instruction set
   • Simple circuitry is cheaper
   • Requires more RAM
   • Compiler has to do more work to translate high-level code into machine code
   • Multiple simple instructions can be executed as fast as a complex one by CISC

3. GPU (Graphics Processing Unit)

   • Designed specifically for graphics so have built-in circuitry and instruction sets for calculations required in common graphics operations
   • Tend to have a large number of cores
   • Able to perform the same instruction on multiple pieces of data at one time (SIMD) so are suited to processing graphics (e.g. transforming points in a polygon or shading pixels)
   • Can be used for: Engineering problems, modelling physical systems, DATA MINING, audio processing, BREAKING PASSWORDS, MACHINE LEARNING

4. Multicore and Parallel Systems

   • Multicore processors have more than one processor incorporated into a single chip
   • SIMD (Single Instruction Multiple Data) - The same instruction operates simultaneously on multiple data locations
   • MIMD (Multiple Instructions Multiple Data) - Different instructions operate concurrently on different data locations