Is x86 RISC or CISC?
cpu, cpu-architecture, x86
Solution
x86 is a CISC architecture. The number of instructions is a big factor as all cisc architectures with all more instructions. Furthermore as instructions are complex in cisc they can take >1 cycle to complete, where as in RISC they should be single cycle. The main differences are found here:
+------------------------------+------------------------------+
| CISC | RISC |
+------------------------------+------------------------------+
| Emphasis on hardware | Emphasis on software |
| . | |
| Includes multi-clock | Single-clock, |
| complex instructions | reduced instruction only |
| . | |
| Memory-to-memory: | Register to register: |
| "LOAD" and "STORE" | "LOAD" and "STORE" |
| incorporated in instruction | are independent instructions |
| . | |
| Small code sizes, | Low cycles per second, |
| high cycles per second | large code sizes |
| . | |
| Transistors used for storing | Spends more transistors |
| complex instructions | on memory registers |
+------------------------------+------------------------------+
For further research consult here: http://www-cs-faculty.stanford.edu/~eroberts/courses/soco/projects/risc/risccisc/
Problem
According to Wikipedia, x86 is a CISC design, but I also have heard/read that it is RISC. What is correct? I'd to also like to know why it is CISC or RISC. What determines if a design is RISC or CISC? Is it just the number of machine language instruction a microprocessors has or are there any other characteristics that determine the architecture?