opcode

Each EVM opcode performs a specific operation and costs a defined amount of gas to execute.每个 EVM 操作码执行一个特定的操作，并在执行时消耗定量的 gas。

Gas optimisation often involves replacing expensive opcodes with cheaper equivalents.Gas 优化通常涉及用更便宜的同类操作码替换昂贵的操作码。