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An operand is the data portion of a 6502 assembly instruction. This is to be distinguished from the opcode, which specifies the operation to perform.


In the example below, JMP is the opcode, $1000 is the operand, and the two combined is the instruction.

0001:4C 00 10  JMP $1000      ; Moves the program counter to $1000.

In this example, DEX is the opcode, but there is no operand since it is implied from the opcode.

0001:CA        DEX            ; Decrements the X index register.