Learn Assembly Programming - Instructions, Mnemonics, Operands, and Opcodes
The term opcode is short for operation code and it tells the processor what operation should be performed. They are generally followed by an argument(s) that further instructs the processor what to do. For all intensive purposes, opcodes are the things in machine language that make the program actually do stuff.
The term mnemonic goes hand-in-hand with opcode, and is simply a friendly term used to describe an opcode. So the mnemonic used to describe the opcode CD is INT, which is an interrupt call. We can say something like "Is INT the mnemonic for the opcode CD?", or conversely "Is CD the opcode for the mnemonic INT?".
Operands are the "arguments" or "parameters" that directly follow a mnemonic. Generally speaking, depending upon the mnemonic used, there can be 0-3 operands following the mnemonic.
Instructions are comprised of both the mnemonic and any operands. Instructions are the executable lines of code in the .text section of your code.
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