题目

英语翻译
The simplest layout is accomplished by locating the application in ROM at address 0 in
the memory map.The application can then branch to the real entry point when it executes
its first instruction at the reset vector at address 0x0.But,there are disadvantages
with this layout.ROM is typically narrow (8 or 16 bits) and slow compared to RAM,
requiring more wait states to access it.This slows down the handling of processor
exceptions,especially interrupts,through the vector table.Moreover,if the vector table
is in ROM,it cannot be modified by the code.
Since RAM is normally faster and wider than ROM,it is better for the vector table and
interrupt handlers if the memory at 0x0 is RAM.Although It is necessary that RAM be
located at 0x0 during normal execution,if RAM is located at address 0x0 on power-up,
there is not a valid instruction in the reset vector entry.Therefore,ROM must be located
at 0x0 at power-up to assure that there is a va

提问时间：2020-10-31

答案

最简单的布局是通过定位在ROM中的应用在地址0内存映射.应用程序可以分支到实际执行时的入口点它的第一条指令在地址0x0复位向量.但是,也有缺点这个布局. ROM是典型的窄（8或16位）和RAM的比较慢,需要更多的等待状态进...