PM511V16 3BSE011181R1 ABB 处理器模块

描述

执行指令阶段（EX，execute），具体实现指令的功能。CPU的不同部分被连接起来，以执行所需的操作。
访存取数阶段（MEM，memory），根据指令需要访问主存、读取操作数，CPU得到操作数在主存中的地址，并从主存中读取该操作数用于运算。部分指令不需要访问主存，则可以跳过该阶段。
结果写回阶段（WB，write back），作为最后一个阶段，结果写回阶段把执行指令阶段的运行结果数据“写回”到某种存储形式。结果数据一般会被写到CPU的内部寄存器中，以便被后续的指令快速地存取；许多指令还会改变程序状态字寄存器中标志位的状态，这些标志位标识着不同的操作结果，可被用来影响程序的动作。
在指令执行完毕、结果数据写回之后，若无意外事件（如结果溢出等）发生，计算机就从程序计数器中取得下一条指令地址，开始新一轮的循环，下一个指令周期将顺序取出下一条指令。 [1] 许多复杂的CPU可以一次提取多个指令、解码，并且同时执行。

PM511V16 3BSE011181R1

Execute instruction stage (EX, execute), specifically implementing the function of the instruction. The different parts of the CPU are connected to perform the required operations.
In the MEM (Access Memory) stage, the CPU accesses main memory and reads operands based on instructions. The CPU obtains the address of the operand in main memory and reads the operand from main memory for computation. If some instructions do not require access to main memory, this stage can be skipped.
The result write back stage (WB, write back) is the final stage where the result data from the execution instruction stage is “written back” to some storage form. The resulting data is generally written to the internal registers of the CPU for quick access by subsequent instructions; Many instructions also change the state of the flag bits in the program status word register, which identify different operation results and can be used to affect program actions.
After the instruction is executed and the result data is written back, if there are no unexpected events (such as result overflow), the computer obtains the address of the next instruction from the program counter and starts a new cycle. The next instruction cycle will sequentially fetch the next instruction. [1] Many complex CPUs can extract multiple instructions at once, decode them, and execute them simultaneously.