小端法与大端法

For ordering the bytes representing an object, there are two common conventions. Consider a w-bit integer having a bit representation [x_w-1, x_w-2, ... , x₁, x₀ ], where x_w-1 is the most significant bit, and x₀ is the least. Assuming w is a multiple of eight, these bits can be grouped as bytes, with the most significant byte having bits [x_w-1, x_w-2, ... , x_w-8], the least significant byte having bits [x₇,x₆,...,x₀], and the other bytes having bits from the middle. Some machines choose to store object in memory ordered from least significant byte comes first-is referred to as little endian. This convention is followed by most Intel-compatible machines. The latter convention-where the most significant byte comes first-is referred to as big endian. This convention is followed by most machines from IBM and Sun Microsystems. Note that we said "most." The conventions do not split precisely along corporate boundaries. For example, both IBM and Sun manufacture machines that use Intel-compatible processors and hence are little endian. Many recent microprocessors are bi-endian, meaning that they can be configured to operate as either little or big-endian machines.