| characteristics | RISC | CISC |
|---|---|---|
| Instruction Set | simple, basic | complex, comprehensive |
| command format | unified, fixed length | variable length |
| assembly line | use | early not used |
| register | more | less |
| memory access | few | many |
| command function | single | complex, multifunctional |
| code | longer | shorter |
| hardware | simpler | more complex |
| execution speed | quick | slow |
| programming difficulty | Disaster | easy |
RISC:
- Pipeline, fixed-length instructions, and a large number of registers are used to improve execution speed.
- The hardware design is simple, but the programming is difficult.
- Pursue high execution efficiency.
CISC:
- Pipelining was not used in the early stage, the instruction format was complicated, the registers were few, and the execution speed was slow.
- Supports complex instructions, simple software design, and easy-to-use programming.
- Pursue high code density and programming flexibility.
In summary, RISC focuses on hardware and processing speed, while CISC focuses more on software and programming. The RISC concept has a great influence on the later CPU design. Modern CPUs have adopted a hybrid design of RISC and CISC, taking into account performance and ease of use.