Understanding CISC (Complex Instruction Set Computer) Architecture and Features – Advantages and Disadvantages
CISC (Complex Instruction Set Computer) Architecture and Features
A complex instruction set computer (CISC) is a type of computer architecture where single instructions can accomplish more than one task. CISC architectures typically have an extensive set of instructions that are varied in length, encoding and execution time, making them more complicated to design and harder to program. However, the increased complexity of such architectures allows for increased code density, meaning more code can be written in fewer instructions, resulting in greater efficiency.
Features of CISC Architecture
- Instructions can take multiple cycles to complete
- Instructions vary in length, encoding and execution time
- Most CISC architectures are stack-based, meaning that memory references are handled automatically
- More efficient code density
- Enhanced features include virtual memory management and support for high-level programming languages
Advantages of CISC Architecture
- Increased code density resulting in greater efficiency.
- Facilitates higher level programming languages.
- Virtual memory management and other enhanced features.
Disadvantages of CISC Architecture
- Increased complexity resulting in higher design and programming costs.
- Reduced performance due to long instruction execution cycles.
- Large amount of memory needed for instruction decoding.