Section 4.6: Pieplined Datapath and Control

An overview of the basic pipelined datapath and its control, as well as walk throughs for LDUR and STUR. This is a critical section to read. Some notes:

The authors intentionally put a mistake in Figure 4.34 (their first version of the pipelined datapath) and they use this datapath to illustrate LDUR and STUR. This mistaken figure is used in the examples from pages 300 to 307; the mistake doesn't particulary affect their LDUR example, and they use the STUR example to point out the problem. Figure 4.40 gives a correct version of the pipelined datapath.
Pay attention to figures 4.42, 4.43, and 4.44; these representations are important.
Figure 4.50 is the most important version of the pipelined datapath in this section; the main difference over earlier versions is that it has the control unit added. Note the generation of control signals in the ID stage and the passing of (some of) these signals along through the pipeline registers to be used in later stages.