Operand

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In mathematics, an operand is one of the inputs (arguments) of an operator. For instance, in

3 + 6 = 9

'+' is the operator and '3' and '6' are the operands.

The number of operands of an operator is called its arity. Based on arity, operators are classified as nullary, unary, binary, ternary etc.

Computer science

In computer programming languages, the definitions of operator and operand are almost the same as in mathematics.

Additionally, in assembly language, an operand is a value (an argument) on which the instruction, named by mnemonic, operates. The operand may be a processor register, a memory address, a literal constant, or a label. A simple example (in the PC architecture) is

MOV   DS, AX

where the value in register operand 'AX' is to be moved into register 'DS'. Depending on the instruction, there may be zero, one, two, or more operands.

See also

• Instruction_set#Number_of_operands