I’m from Norway, but I live in Bangkok, Thailand. Before I started VHDLwhiz, I worked as an FPGA engineer in the defense industry. I earned my master’s degree in informatics at the University of Oslo.
Similar Posts
Why you always need a testbench
As most hardware engineers, I started off my computer science career by learning a sequential programming language. The first language I learned at the University of Oslo was Java. While it’s not considered to be the most exciting language today, at the time, Java was at the pinnacle of its popularity. The engineers who built…
Using Integrated Logic Analyzer (ILA) and Virtual Input/Output (VIO)
This tutorial covers using the Integrated Logic Analyzer (ILA) and Virtual Input/Output (VIO) cores to debug and monitor your VHDL design in the Xilinx Vivado IDE. In many cases, designers are in need to perform on-chip verification. That is, gaining access to an internal signal’s behavior in their FPGA design for verification purposes. One option…
How to use Signed and Unsigned in VHDL
The signed and unsigned types in VHDL are bit vectors, just like the std_logic_vector type. The difference is that while the std_logic_vector is great for implementing data buses, it’s useless for performing arithmetic operations. If you try to add any number to a std_logic_vector type, ModelSim will produce the compilation error: No feasible entries for…
Should I learn VHDL if Verilog is becoming more popular?
Which HDL is the most popular, and should I learn VHDL or Verilog? That’s a question I often get asked, and it’s understandable. People want to future-proof their learning by betting on the winning horse. But which one is it, and does it matter?
How to create your first VHDL program: Hello World!
When learning a new programming language, I always like to start by learning how to print. When you master outputting “Hello World!”, you know that you’ve got the environment working. It also shows you the basic skeleton of the language, the bare minimum code required to produce any output. You might be thinking: but VHDL…
How to use an impure function in VHDL
An impure function can read or write any signal within its scope, also those that are not on the parameter list. We say that the function has side effects. What we mean by “side effects” is that it is not guaranteed that the function will return the same value every time it is called with…
First of all, thank you so very much!
These are by far the most comprehensible tutorials I have come across like ever!
Brilliant work.
So here my two cents out of gratitude:
Basic VHDL Quiz – part 4
Which statement is not true?
Answer 3 : The return statement cannot be omitted.
-> Correct
So the return statement CAN be omitted???
“Unlike in most other programming languages, the return keyword is mandatory in functions in VHDL.”
Confused by double negation. Me or you 😉
Good catch! I’ve changed the answer now. I was trying to make you think, but in the process I confused myself too 🙂
“The return-keyword cannot be used in a procedure”. I believe that this is incorrect, e.g.
https://web.archive.org/web/20200629023040/http://vhdl.renerta.com:80/source/vhd00060.htm
It is true, of course, that you cannot return a value with it, that’s the only (?) difference between procedures and functions. But, as in other languages, you can use “return” as control flow statement to “force an exit”.
You are right! I missed the possibility of using return statements in procedures without returning a value. According to the Renata link you posted, functions must return a value, while procedures can have return statements, but then without a return value.
I am changing this question.