Introducing data types

All computer programming languages need variables. These are places in memory or registers that store values that the program that's running can access. Hardware Design Languages (HDLs) are a little different in that you are building hardware. There are variable equivalents in terms of storage/sequential logic, which we'll discuss in the next chapter, but we also need wires to move data around the hardware we're building using the FPGA routing resources, even if they are never stored:

Figure 2.1 – Program flow versus HDL flow

As we can see, in a traditional flow, you have a computer that has a processor and memory. The program flows linearly; however, with modern machines, there are increasing levels of parallelism. When you write SystemVerilog, you are using data types to create hardware that will store or move data around physically from Lookup Tables (LUTs) to LUTs. If you want to use external memory, which is...