It Isn’t WebAssembly, But It Is Assembly In Your Browser

April 11, 2023 by Al Williams 18 Comments

You might think assembly language on a PC is passe. After all, we have a host of efficient high-level languages and plenty of resources. But there are times you want to use assembly for some reason. Even if you don’t, the art of writing assembly language is very satisfying for some people — like an intricate logic puzzle. Getting your assembly language fix on a microcontroller is usually pretty simple, but on a PC there are a lot of hoops to jump. So why not use your browser? That’s the point of this snazzy 8086 assembler and emulator that runs in your browser. Actually, it is not native to the browser, but thanks to WebAssembly, it works fine there, too.

No need to set up strange operating system environments or link to an executable file format. Just write some code, watch it run, and examine all the resulting registers. You can do things using BIOS interrupts, though, so if you want to write to the screen or whatnot, you can do that, too.

The emulation isn’t very fast, but if you are single-stepping or watching, that’s not a bad thing. It does mean you may want to adjust your timing loops, though. We didn’t test our theory, but we expect this is only real mode 8086 emulation because we don’t see any protected mode registers. That’s not a problem, though. For a learning tool, you’d probably want to stick with real mode, anyway. The GitHub page has many examples, ranging from a sort to factorials. Just the kind of programs you want for learning about the language.

Why not learn on any of a number of other simulated processors? The 8086 architecture is still dominant, and even though x86_64 isn’t exactly the same, there is a lot of commonalities. Besides, you have to pretend to be an 8086, at least through part of the boot sequence.

If you’d rather compile “real” programs, it isn’t that hard. There are some excellent tutorials available, too.

Wolverine Gives Your Python Scripts The Ability To Self-Heal

April 9, 2023 by Donald Papp 38 Comments

[BioBootloader] combined Python and a hefty dose of of AI for a fascinating proof of concept: self-healing Python scripts. He shows things working in a video, embedded below the break, but we’ll also describe what happens right here.

The demo Python script is a simple calculator that works from the command line, and [BioBootloader] introduces a few bugs to it. He misspells a variable used as a return value, and deletes the subtract_numbers(a, b) function entirely. Running this script by itself simply crashes, but using Wolverine on it has a very different outcome.

In a short time, error messages are analyzed, changes proposed, those same changes applied, and the script re-run.

Wolverine is a wrapper that runs the buggy script, captures any error messages, then sends those errors to GPT-4 to ask it what it thinks went wrong with the code. In the demo, GPT-4 correctly identifies the two bugs (even though only one of them directly led to the crash) but that’s not all! Wolverine actually applies the proposed changes to the buggy script, and re-runs it. This time around there is still an error… because GPT-4’s previous changes included an out of scope return statement. No problem, because Wolverine once again consults with GPT-4, creates and formats a change, applies it, and re-runs the modified script. This time the script runs successfully and Wolverine’s work is done.

LLMs (Large Language Models) like GPT-4 are “programmed” in natural language, and these instructions are referred to as prompts. A large chunk of what Wolverine does is thanks to a carefully-written prompt, and you can read it here to gain some insight into the process. Don’t forget to watch the video demonstration just below if you want to see it all in action.

While AI coding capabilities definitely have their limitations, some of the questions it raises are becoming more urgent. Heck, consider that GPT-4 is barely even four weeks old at this writing.

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Revisiting Borland Turbo C And C++

April 8, 2023 by Maya Posch 76 Comments

Looking back on what programming used to be like can be a fascinatingly entertaining thing, which is why [Tough Developer] decided to download and try using Turbo C and C++, from version 1.0 to the more recent releases. Borland Turbo C 1.0 is a doozy as it was released in 1987 — two years before the C89 standardization that brought us the much beloved ANSI C that so many of us spent the 90s with. Turbo C++ 1.0 is from 1991, which precedes the standardization of C++ in 1998. This means that both integrated development environments (IDEs) provide a fascinating look at what was on the cutting edge in the late 80s and early 90s.

Online help and syntax coloring in Turbo C++.

It wasn’t until version 3.0 that syntax highlighting was added, with the IDE’s focus being mostly on features such as auto-indentation and tool integration. Version 2.0 added breakpoints and further integration with the debugger and other tools, as well as libraries such as the Borland Graphics Interface (BGI). Although even editors like Notepad++ and Vim probably give these old IDEs a run for their money nowadays, they were totally worth the money asked.

Those of us that have been around long enough to have gotten their start in C++ by using the free Turbo command line tools in the 1990s, or lived through the rough, early days of GCC 2.x+ on Linux, will remember that a development environment that Just Worked^© was hard to obtain without shelling out some cash. Within that environment Turbo C and C++ and later Visual Studio and others served a very grateful market indeed.

Beyond the IDE itself, these also came with language documentation, as in the absence of constant internet access, referencing APIs and syntax was done using dead-tree reference books or online documentation. Here “online” meaning digital documentation that came provided on a CD and which could be referenced from within the IDE.

[Tough Developer] walks the reader through many features of the IDE, which includes running various demos to show off what the environment was capable of and how that in turn influenced contemporary software and games such as Commander Keen in Keen Dreams. While we can’t say that a return to Turbo C is terribly likely for the average Hackaday reader, we do appreciate taking a look back at older languages and development environments — if for no other reason than to appreciate how far things have come since then.

Minecraft Finally Gets Multi-Threaded Servers

April 3, 2023 by Matthew Carlson 33 Comments

Minecraft servers are famously single-threaded and those who host servers for large player bases often pay handsomely for a server that has gobs of memory and ripping fast single-core performance. Previous attempts to break Minecraft into separate threads haven’t ended successfully, but it seems like the folks over at [PaperMC] have finally cracked it with Folia.

Minecraft is one of (if not the most) hacked and modded games in history. Mods have been around since the early days, made possible by a dedicated group who painstakingly decompiled the Java bytecode and reverse-engineered it. Bukkit was a server mod back in the Alpha days that tried to support plugins and extend the default Minecraft. From Bukkit, Spitgot was forked. From Spitgot, Paper was forked, which focused on performance and gameplay mechanics. And now from Paper, Folia is a new fork focused on multi-threading.

A Minecraft world is split up into worlds (such as the nether or the overworld) and chunks. Chunks are 16x16xZ vertical columns of blocks. Folia breaks up sections of chunks into regions that can be ticked independently. Of course, moving to a multi-threaded model will cause existing plugins to fail. Very little was made thread-safe and the idea is that data cannot move easily across ticking regions. Regions tick in parallel, not synchronously.

Naturally, the people benefiting from Folia the most are those running servers that support hundreds of players. On a server with a vanilla-like configuration only around a hundred or so players can be online. Increasing single-core performance isn’t usually an option past this point. By moving to other cores, suddenly you can scale out significantly without restoring to complex proxying. Previous attempts have had multiple Minecraft servers and then synced players and entities between them. Of course, this can cause its own share of issues.

It’s simply incredible to us what the modding community continues to develop and create. It takes deep patience to reverse-engineer the system and rearchitect it from the outside. The Folia codebase is available on GitHub under a GNU GPL 3.0 license if you’d like to look through it.

How Much Programming Can ChatGPT Really Do?

March 25, 2023 by Bryan Cockfield 50 Comments

By now we’ve all seen articles where the entire copy has been written by ChatGPT. It’s essentially a trope of its own at this point, so we will start out by assuring you that this article is being written by a human. AI tools do seem poised to be extremely disruptive to certain industries, though, but this doesn’t necessarily have to be a bad thing as long as they continue to be viewed as tools, rather than direct replacements. ChatGPT can be used to assist in plenty of tasks, and can help augment processes like programming (rather than becoming the programmer itself), and this article shows a few examples of what it might be used for.

AI comments are better than nothing…probably.

While it can write some programs on its own, in some cases quite capably, for specialized or complex tasks it might not be quite up to the challenge yet. It will often appear extremely confident in its solutions even if it’s providing poor or false information, though, but that doesn’t mean it can’t or shouldn’t be used at all.

The article goes over a few of the ways it can function more as an assistant than a programmer, including generating filler content for something like an SQL database, converting data from one format to another, converting programs from one language to another, and even help with a program’s debugging process.

Some other things that ChatGPT can be used for that we’ve been able to come up with include asking for recommendations for libraries we didn’t know existed, as well as asking for music recommendations to play in the background while working. Tools like these are extremely impressive, and while they likely aren’t taking over anyone’s job right now, that might not always be the case.

Picture of the miniJen structure on a presentation desk

A Jenkins Demo Stand For Modern Times

March 24, 2023 by Arya Voronova 7 Comments

Once you’re working on large-scale software projects, automation is a lifesaver, and Jenkins is a strong player in open-source automation – be it software builds, automated testing or deploying onto your servers. Naturally, it’s historically been developed with x86 infrastructure in mind, and let’s be fair, x86 is getting old. [poddingue], a hacker and a Jenkins contributor, demonstrates that Jenkins keeps up with the times, with a hardware demo stand called miniJen, that has Jenkins run on three non-x86 architectures – arm8v (aarch64), armv7l and RISC-V.

There’s four SBCs of different architectures involved in this, three acting as Jenkins agents executing tasks, and one acting as a controller, all powered with a big desktop PSU from Pine64. The controller’s got a bit beefier CPU for a reason – at FOSDEM, we’ve seen it drive a separate display with a Jenkins dashboard. It’s very much a complete demo for its purpose, and definitely an eyecatcher for FOSDEM attendees passing by the desk! As a bonus, there’s also a fascinating blog post about how [poddingue] got to running Jenkins on RISC-V in particular.

Even software demonstrations get better with hardware, and this stood out no doubt! Looking to build a similar demo, or wondering how it came together? [poddingue] has blog posts on the demo’s structure, a repo with OpenSCAD files, and a trove of videos demonstrating the planning, design and setup process. As it goes with continuous integrations, we’ve generally seen hackers and Jenkins collide when it comes to build failure alerts, from rotating warning lights to stack lights to a Christmas tree; however, we’ve also seen a hacker use it to keep their firmware size under control between code changes. And, if you’re wondering what continuous integration holds for you, here’s our hacker-oriented deep dive.

The X Macro: A Historic Preprocessor Hack

March 16, 2023 by Al Williams 45 Comments

If we told you that a C preprocessor hack dated back to 1968, you’d be within your rights to remind us that C didn’t exist in 1968. However, assemblers with preprocessors did, and where there is a preprocessor, there is an opportunity to do clever things. One of those things is the so-called X macro, which saw a lot of use in DEC System 10 code but probably dates back even earlier. You can still use it today if you like, even though there are, of course, other arguably better ways to get the same result. However, the X macro can be very efficient, and you may well run into it in some code, too.

Background

Preprocessing used to be a staple of programming. The idea is that code is manipulated purely at the text level before it is compiled. These days, languages with a preprocessor usually handle it as part of the compiler, but you can also use an external preprocessor like m4 for more sophisticated uses.

Modern languages tend to provide other ways to accomplish many of the tasks handled by the preprocessor. For example, if you have a constant you want to set at compile time, you could say:

int X = 32;
y = X;

But then you’ve created a real variable along with the overhead that might entail. A smart compiler might optimize it away for you, but you can be sure by writing:

#define X 32
y = X;

A modern compiler would prefer you to write:

const int X=32;
y = X;

But there are still some common uses for macros, like including header files. You can also make more sophisticated macros with arguments so you don’t incur a function call penalty, although modern usage would be to mark those functions as inline.

The Problem

Which brings us to the X macro. With all great hacks, there is first a problem to solve. Imagine you have a bunch of electronic parts you want to deal with in your code. You don’t want a database, and you don’t want to carry a bunch of strings around, so you define an enumerated type:

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