Characteristics of a RISC architecture:
- Emphasis on software;
- Single-clock, reduced instruction only;
- Uniform instruction format, using a single Word with the opcode in the same bit positions in every instruction, demanding less decoding;
- Identical general purpose registers, allowing any register to be used in any context, simplifying compiler design;
- Simple addressing modes. Complex addressing performed via sequences of arithmetic and/or load-store operations;
- Typically larger code sizes;
- Few data types in hardware;
Characteristics of a CISC architecture:
- Emphasis on hardware;
- Includes multi-clock complex instructions;
- Small code sizes;
- Complex data types in hardware; some CISCs have byte string instructions, or support complex numbers
