Examine Source Code To Assembly Mapping With PenguinTrace

May 9, 2019 by Ted Yapo 23 Comments

C-programmers who don’t have a mental model of what’s going on underneath their thin veneer of abstraction above assembly code are destined for trouble. In order to provide a convenient way to understand what C-code gets compiled to and how it runs on the machine, [Alex Beharrell] has created penguinTrace, a program which allows you to see what instructions your code compiles to, and examine how it executes.

While you can get somewhat similar functionality out of standard debuggers, penguinTrace was purpose-built to facilitate exploration of how the whole process works. You can single-step through the instructions your code compiled to, examine variables, and look at the stack — the usual debugger stuff — but structured more for exploration and learning than full-on debugging. Based on our experiences when we learned low-level programming, anything that can help novices build that all-important mental picture of what’s going on underneath is a good thing. But, since it was written with a secondary purpose of learning how debuggers themselves work, it’s a great opportunity for exploring that space, too.

The UI harnesses CodeMirror to provide a browser-based interface, and is configurable to use Clang or GCC for compilation. It supports AMD64/X86-64 and AArch64 architectures, and will run on Windows using WSL: if you’ve got a PC running Linux, a Raspberry Pi, or a Windows box, you’re good to go. The code is AGPL-licensed and available on GitHub. So, if you want to gain a better understanding of what happens when you compile and run “hello, world,” grab a copy and start exploring.

This isn’t the only way to debug, though – we previously featured an application that allows a type of debugging for the Arduino platform.

35C3: Biggest Communication Congress, Yet Little Chaos

January 10, 2019 by Elliot Williams 4 Comments

Every year for the past 35 years, the German Chaos Computer Club has met just after Christmas for a few days of “Spaß am Gerät” — having fun with the machines. And that’s everything from trying to bring an old PDP-8 back into running condition to forging new software to replace the old and busted social media platforms that permeate our lives. The sum total of around 17,000 people doing the nerdy stuff that they love, and sharing it together, is both amazing and inspiring. Four days of little sleep and much socializing later, I bet there was still another four days’ worth of stuff to see.

The official theme this year was “Refreshing Memories” which honestly sounds a bit too much like a cola slogan, but was a great opportunity to think back on the hacks of the past that got us where we are. Assemblies put up shrines to their hacker heroes of the past. Retro computers were everywhere, in the talks and on the floor. This year’s Congress was a great time to look back and remember, but also to create new memories for the future. On that front, it was a total success.

But the unofficial theme this year was “Smooth Running”. Everything went very well, which is no small feat considering that the infrastructure, decoration, security, and even the medical response teams are from the Chaos community. It’s the depth of engagement that makes this work: of the 17,000 people who showed up, just over 4,000 of them volunteered for “angel” shifts — meaning they helped guard the doors, staff the info desks, or build up or tear down. It was the largest ever CCC, and you could feel it, but they pulled it off, and then some.

The angels are geeks just like you and me, and since everything went so smoothly, they had time to play. For instance, the phone operations people offer DECT phone service so that attendees can bring in their home phones and use them at Congress. In years past, the lines to register and enroll phones were painfully long. This year, it all happened online, and the result is that the phone ops crew got bored. That explains how they had time to establish roaming home-phone wireless service in some of the normal Leipzig city trams. Wait, what?

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New Game, Old Ways: Cramming An NES Game Into 40 KB

January 9, 2019 by Dan Maloney 27 Comments

Why would anyone bother to create new content for a console system that’s staring down its 40th birthday? Perhaps just for the challenge of fitting a game into 40 kilobytes of storage.

That at least seems to be the motivation behind [Morphcat Games] pending release of Micro Mages, a new game for the Nintendo Entertainment System console that takes its inspiration from Super Mario Bros. The interesting bit here is how they managed to stuff so much content into so little space. The video below goes into great detail on that, and it’s a fascinating lesson in optimization. The game logic itself is coded in assembler, which of course is far more efficient than higher level languages. Even so, that took 32 kB of ROM, leaving a mere 8 kB for background elements and foreground sprites.

Through a combination of limited sprite size, tiling of smaller sprites to make larger characters, and reusing tiles by flipping them horizontally or vertically, an impressively complete palette of animated characters was developed. Background elements were similarly deconstructed and reused, resulting in a palette of tiles used to generate all the maps for the game that takes up just 60 bytes. Turning those into playable levels involves more mirroring and some horizontal shifting of tiles, and it looks like quite an engaging playfield.

Yes, there’s a Kickstarter for the game, but we’re mainly intrigued by what it takes to cram a playable game into so little space. Don’t get us wrong – we love the Retro Pie builds too, but seeing the tricks that early game developers relied upon to make things work really gets the creative juices flowing.

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Delicious Vector Game Console Runs Pac-Man, Tetris, And Mario

December 26, 2018 by Dan Maloney 20 Comments

The only question we have about [mitxela]’s DIY vector graphics game console is: Why did he wait five years to tell the world about it?

Judging by the projects we’ve seen before, from his tiny LED earrings to cramming a MIDI synthesizer into both a DIN plug and later a USB plug, [mitxela] likes a challenge. And while those projects were underway, the game console you’ll see in the video below was sitting on the shelf, hidden away from the world. That’s a shame, because this is quite a build.

Using a CRT oscilloscope in X-Y mode as a vector display, the console faithfully reproduces some classic games, most of which, curiously enough, were not originally vector games. There are implementations of the Anaconda, RetroRacer, and AstroLander minigames from Timesplitter 2. There are also versions of Pac-Man, Tetris, and even Super Mario Brothers. Most of the games were prototyped in JavaScript before being translated into assembly and placed onto EEPROM external cartridges, to be read by the ATMega128 inside the console. Sound and music are generated using the ATMega’s hardware timers, with a little help from a reverse-biased transistor for white noise and a few op-amps.

From someone who claims to have known little about electronics at the beginning of the project, this is pretty impressive stuff. Our only quibbles are the delay in telling us about it, and the lack of an Asteroids implementation. The former is forgivable, though, because the documentation is so thorough and the project is so cool. The latter? Well, one can hope.

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Clever Wedges That Will Increase Your PCB Assembly Yield

December 22, 2018 by Brian Benchoff 22 Comments

If there’s one thing that will bring down the yield of your PCB assembly, it’s your solder paste. Put too much on, and you’ll get bridged leads. If you don’t put enough on, that pad might not make good contact. [ScalarElectric] has an amazing trick that’s sure to astonish and astound. Just use wedges and you’ll get better yield with fine-pitched components.

The trick here is to define the cream/solder paste layer of each package as a wedge on each pad instead of the usual rectangle. This gives a few benefits, the largest being the increased gap between paste shapes. You’re also getting a reduction in the total amount of paste applied, and a subsequent improvement in yield. (Reportedly, we’d love to see some data on this.)

PCB design tools usually have a way to alter the size of the cream/solder paste layer of a design, and indeed one option is to simply shrink the size of the paste layer elements. The trick to the wedges is increasing the total distance between solderpaste blobs while keeping the total amount of solderpaste high. This technique can be used down to 0.5mm pitch parts, and everything works like a charm.

While this is a little outside of our wheelhouse here at Hackaday — it is, after all, a novel use of existing tools that is mostly applicable to electronic design and production. [Ed Note: Sarcasm.] You can check out a few pics of this technique in the slideshow below. If you test this technique out, be sure to let us know how it went!

Learn To Optimize Code In Assembly… For Android

October 30, 2018 by Bryan Cockfield 11 Comments

When programming a microcontroller, there are some physical limitations that you’ll come across much earlier than programming a modern computer, whether that’s program size or even processor speed. To make the most use of a small chip, we can easily dig into the assembly language to optimize our code. On the other hand, modern processors in everyday computers and smartphones are so fast and have so much memory compared to microcontrollers that this is rarely necessary, but on the off-chance that you really want to dig into the assembly language for ARM, [Uri Shaked] has a tutorial to get you started.

The tutorial starts with a “hello, world” program for Android written entirely in assembly. [Uri] goes into detail on every line of the program, since it looks a little confusing if you’ve never dealt with assembly before. The second half of the program is a walkthrough on how to actually execute this program on your device by using the Android Native Deveolpment Kit (NDK) and using ADB to communicate with the phone. This might be second nature for some of us already, but for those who have never programmed on a handheld device before, it’s worthwhile to notice that there are a lot more steps to go through than you might have on a regular computer.

If you want to skip the assembly language part of all of this and just get started writing programs for Android, you can download an IDE and get started pretty easily, but there’s a huge advantage to knowing assembly once you get deep in the weeds especially if you want to start reverse engineering software or bitbanging communications protocols. And if you don’t have an Android device handy to learn on, you can still learn assembly just by playing a game.

A Close Look At The Prusa I3 MK3

October 22, 2018 by Tom Nardi 63 Comments

The Prusa i3 MK3 is, for lack of a better word, inescapable. Nearly every hacker or tech event that I’ve attended in 2018 has had dozens of them humming away, and you won’t get long looking up 3D printing on YouTube or discussion forums without somebody singing its praises. Demand for Prusa’s latest i3 printer is so high that there’s a literal waiting list to get one.

At the time of this writing, over a year after the printer was officially put up for sale, there’s still nearly a month lead time on the assembled version. Even longer if you want to wait on the upgraded powder coated bed, which has unfortunately turned out to be a considerable production bottleneck. But the team has finally caught up enough that the kit version of the printer (minus the powder coated bed) is currently in stock and shipping next day.

I thought this was a good a time as any to pull the trigger on the kit and see for myself what all the excitement is about. Now that I’ve had the Prusa i3 MK3 up and running for a couple of weeks, I can say with confidence that it’s not just hype. It isn’t a revolution in desktop 3D printing, but it’s absolutely an evolution, and almost certainly represents the shape of things to come for the next few years.

That said, it isn’t perfect. There’s still a few elements of the design that left me scratching my head a bit, and some parts of the assembly weren’t quite as smooth as the rest. I’ve put together some of those observations below. This isn’t meant to be a review of the Prusa i3 MK3 printer, there’s more than enough of those already, but hopefully these assorted notes may be of use to anyone thinking of jumping on the Prusa bandwagon now that production has started really ramping up.

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