operandsize
Operand size is the bit width of the data that a processor instruction operates on. It specifies how many bits are read from a source operand, how many are written to a destination, and how the result should be interpreted by the arithmetic or logic unit. Common sizes are 8, 16, 32 and 64 bits, corresponding to bytes, words, doublewords, and quadwords; some architectures support additional or nonstandard sizes via special instructions.
Control and variation: In many CPUs, the basic data path is fixed, but the effective operand size
Impact and usage: Operand size affects instruction encoding length, register selection, and how values are extended
See also: data width, word size, byte, register, instruction encoding.