Because most devices are separated from the CPU by a bus, which is much slower to send data across than it is to write to CPU registers or (cached) memory.

因为大多数设备是分开的CPU总线，慢得多的发送数据跨比写信给CPU寄存器或内存(缓存)。

youdao

Because most devices are separated from the CPU by a bus, which is much slower to send data across than it is to write to CPU registers or (cached) memory.

因为大多数设备是分开的CPU总线，慢得多的发送数据跨比写信给CPU寄存器或内存(缓存)。

youdao