ISA features to support efficient compiler /code
Regularity: Three components of instruction set : operation, data types and addressing modes - should be orthogonal.
- Two aspects of an architecture are said to be orthogonal if they are independent of each other.
- Example: VAX ‘s arithmetic operations are equally applicable to register or memory operands.
Provide primitives and not solutions: Features that match a particular HLL feature are often not usable by other HLL or other statements. Example: Index register to support arrays. Instead a general purpose register would serve the purpose and other situations well.