I am a Specialist Professor in the Department of Computer Science and Software Engineering (CSSE) and Director of the Monmouth University Cybersecurity Research Center (CRC) at Monmouth University in central New Jersey. As a researcher, my focus is broadly on all things cybersecurity: from its intersections with…
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In my never ending quest to have oksh support every C compiler in existence, I have ported two more C compilers to OpenBSD . They are chibicc and kefir. As always, let's review them and at the end I'll have links to unofficial ports so that you can play around with these C compilers.
As a fun afternoon challenge, I decided to write a C program that looked nothing like C. Not necessarily obfuscated, though there is a competition for that if you are so inclined.
When we wrote our assembler we made many design choices that helped us cut down on the complexity of the assembler itself. One of those decisions was to have the assembler directly output executables. That was a good choice in that it allowed us to quickly test as we were developing: once we implemented an opcode, we…
Two new language frontends have been added to GCC : Modula-2 and Rust . I think this is great news on both accounts: having a Wirth language in GCC fills my childhood heart with joy (though I do wish GNU Pascal can one day be revived and mainlined, as Pascal was the first non- BASIC language I learned). And Rust…
Continuing on from our tiny snake game , let's explore more into how binaries work on Unix. Let's figure out how our programs come to obtain their argc and argv parameters.
In my never ending quest to have oksh support every C compiler in existence, I sometimes find C compilers in places you wouldn't expect them. Today, I'd like to demonstrate the C compiler built into the Digital Mars D compiler, or DMD for short. Recent versions of DMD have a complete C11 compiler built in named…
I think we all knew this might be coming once we finished up with our assembler . While we can in theory solve any computable problem by writing the appropriate assembly for our assembler, writing assembly code can be a bit more cumbersome than a high-level language. There is a reason why we did not write our…
We wrote a Brainfuck compiler back in April . That one developed a simple architecture to support multiple backends. Today, I want to write a new Brainfuck compiler. One that can only run on a single system, OpenBSD /amd64. And one that is as small as I can possibly make it. I broke into the sub-256 bytes club with my…
Yes, I am aware that I am interrupting our self-hosting PL/0 compiler series but I think it will be worth it. Earlier today, I got the J language system running on OpenBSD . I find it important to write these up, because it helps me preserve my own knowledge of what I did and hopefully it will help others porting…
I am on a number of different compiler mailing lists. One of those is the mailing list for the Tiny C Compiler . Imagine my surprise when a recent email mentioned our latest series and suggested trying a similar approach to improve the code generator in TCC. I was interested to see if there were any low-hanging fruit…
Tokenizing the source code input is a great start for our compiler. Now let's turn our attention to parsing the PL/0 grammar. Once we have finished with the parser, the front end of our compiler will be finished and we will have a PL/0 validator. This is a program that can read in PL/0 source code and inform the user…
I got GDC , the GNU D Compiler, working on OpenBSD . Supporting D has been a very long time coming. Here's the story of how we got here and where we need to go next.
Today, I wanted to see if I could out-compile my C compiler. I added a hand-compiled assembly version of echo from our previous coding exercise and added a new make target, make asm , that will assemble it. Let's look at our hand-compiled assembly and compare it to our C compiler and ask whether or not it was worth it.
When it rains it pours. After making a splash with D , 1 I remembered that some time ago I began an attempt to bring the GNU Modula-2 compiler to OpenBSD . Because why not? Modula-2 is a language that exists and has compiler implementations. I guess my goal is to bring all the languages and compilers to OpenBSD. And…
People appear to enjoy the blog posts about me porting different compilers to OpenBSD . What I would like to do for the next couple of posts beginning with this one is to take a step back and de-complexify these programs. Both the D compiler and the GNU Modula-2 compiler are highly complex pieces of software. But at…