Why use `instr_fetch` but not `swaddr_read` directly? about ics2015 HOT 3 CLOSED

Using instr_fetch can tell us whether a memory accessing is related to instruction or data. This makes the code more readable. Besides, this can make it easy to implement Icache and Dcache in the future. Just a design consideration.

from ics2015.

That's reasonable. But I think we cannot really speed up our Nemu CPU by simulating cache in memory...

from ics2015.

Yes, you are right. Simulating cache will hurt the performance. But NEMU is designed for teaching. Students learn how cache works in class. Implementing a cache by simulation and put it into a system(NEMU) will give them better understanding. Facing the trade off between teaching and performance, we prefer the former.

from ics2015.