An important issue in computer architecture and compiler design is the way that memory is addressed, that is, the way that locations in memory are specified and interpreted in the instruction set. As memory writes and reads are fundamental to a CPU's operation, this matter is fundamental to computer architecture. During the program execution, the addressing hardware converts the instruction's address specifications into effective addresses. This process of converting address is called address resolution. When operands are taken from register(s), it is called register addressing. These operands are called register operands. If operands are from memory locations, they are called memory operands.

Nearly all instruction sets are byte addressed and provide access for bytes (8 bits), half-words (16 bits) and words (32 bits). Newer machines commonly provide access for double words (64 bits) as well. Within a word, bytes may be ordered in two ways--the "Little Endian" order puts the byte...