unused instruction是什么意思

用法例句

NIOS II soft-core is suggested as the kernel of embedded system,custom peripheral and custom instruction are defined as interface circuit,and intergrated chips-IME6400 and BT835 are proposed as peripheral circuit.

系统以NIOS II软核作为嵌入式系统核心、自定义用户外设和用户指令为接口电路I、ME 6400及BT835为外围电路,并采用DMA传输视频监控数据以及UART传输摄像头控制指令。