Load-Store Units

Chapter 1 discussed the difference between instructions that access memory (loads and stores) and instructions that do actual computation (integer instructions, floating-point instructions, etc.). Just like integer instructions are executed in the IUs and floating-point instructions are executed in the FPUs, memory access instructions have their own specialized execution units in the form of one or more load-store units (LSUs).

Chapter 1 also discussed the fact that in order to access memory via a load or a store, it’s usually necessary to perform an address calculation so the processor can figure out the location in memory that it should access. Even though such address calculations are just simple integer operations, they’re ...

Get Inside the Machine now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.