单周期和多周期数据路径之间的差异

1. 单周期数据路径：
Single Datapaths 相当于原来的单周期 datapath 数据存储器只有一个地址输入。实际的内存操作可以通过 MemRead 和 MemWrite 控制信号来确定。指令和数据有单独的存储器。有 2 个用于基于 PC 的计算的加法器和一个 ALU。控制信号相同。

2. 多周期数据路径：
多周期数据路径将指令分解为单独的步骤。每一步都需要一个时钟周期 每个功能单元在一条指令中可以多次使用，只要在不同的时钟周期中使用即可。它减少了所需的硬件数量。它减少了平均指令时间。

单周期和多周期数据路径之间的差异：

S.No.	Single Cycle Datapath	Multiple Cycle Datapath
1	Instructions are not subdivided.	Instructions are divided into artitoray number of steps.
2	Clock cycles are long enough for the lowest instruction.	Clock cycles are short but long enough for the lowest instruction.
3	There are only 1 instruction that can be executed at the same time.	There are only 1 instruction that can be executed at the same time.
4	There is 1 cycle per instruction, i, e., CPI = 1.	There is a variable number of clock cycles per instructions.
5	Control unit generates signals for the entire instruction.	Control unit generates signals for the instruction’s current step and keeps track of the current step.
6	There is duplicate hardware, because we can use a functional unit for at most one subtask per instruction.	There is no duplicate hardware, because the instructions generally are broken into single FU steps.
7	Extra registers are not required.	Extra registers are required to hold the result of one step for use in the next step.
8	Performance is baseline.	Performance is slightly slower to mederaletly faster than single cycle, latter when the instructions steps are well balanced and a significantly fractions of the instructions take less than the maximum number of cycles.