Mark-James McDougall

Cropped iPhone screenshot showing a hex-view of “48.rom”. Two consecutive bytes among many are highlighted. (Other fondleslabs may be available, YMMV).

Holy hexadecimal Batman! Evidently they make hex editors for Trouserphones now, so you can scrutinise the ZX Spectrum ROM code on-the-go! (Or indeed, on-the-couch).

GitHub - TechPaula/LT6502: A 6502 based laptop design A 6502 based laptop design. Contribute to TechPaula/LT6502 development by creating an account on GitHub.

LT6502: a 6502-based laptop design

#gamedevelopment #indiedev #gamedev

Paula Maddox's LT6502 is a modern laptop design based on the retro 6502 microprocessor: github.com/TechPaula/LT...

Bit Masking Made Easy with .NET Enum Flags C# enums in conjunction with FlagsAttribute can be a powerful tool when working with bitfields, helping to reduce cognitive load while also making it clear what bits in the mask are being changed.

#csharp enums in conjunction with the Flags attribute can be a powerful tool when working with #bitfields.

Discover two examples of how I used them to make my 6502 microprocessor #emulator code easier to reason about:

markjames.dev/blog/bit-mas...

#dotnet

Keyboards laying in a snowbank.

Spotted an IBM #ModelM laying in a snowbank while running errands earlier this afternoon.

#retrocomputing #vintagecomputing #mechanicalkeyboard #vintagetech

OpenSky.NET is a #dotnet library that I’ve been developing for interacting with the #OpenSky Network REST API.

#ads-b #airplanes #atc #adsb #flarm #aviation #mode-s #vhf

github.com/markjamesm/O...

New blog post: Remote diagnosing a PET 2001 video fault from one photograph.
blog.tynemouthsoftware.co.uk/2026/02/diag...
Includes a look at how the PET video system works with redrawn schematics.
It also turns out to be a surprisingly early PET 2001.

A die photo of the 8087 chip, with the main functional blocks labeled. The chip is a tan rectangle with complex patterns in dark brown. Many of the patterned regions are textured rectangles. One of the largest rectangles is the microcode ROM in the middle. The bottom half of the chip is the datapath, performing operations on floating-point numbers. The instruction decoding happens in the upper left. Around the edges of the chip, bond wires connect the chip to the 40 external pins, but the pins are not visible, just short segments of the bond wires.

In 1980, Intel released the 8087 floating-point chip, making math much faster. I'm reverse-engineering this chip, 46 years later. Most of its instructions are implemented in microcode, but some are implemented in hardware. Let's look at the circuitry that decodes instructions and decides what to do.

Screenshot of the MusicSharp interface.

MusicSharp is an #opensource, cross-platform #TUI music player that I developed using C#. A fully standalone application (no #dotnet runtime required), it supports MP3, FLAC, WAV, & internet radio streams!

There’s still more work to be done, so feel free to contribute!

github.com/markjamesm/M...

YouTube video by Pixelmusement Road Warrior / Quarantine II - ADG Episode 353

New Ancient DOS Games episode uploaded and ready to watch! youtu.be/ADZKPcsbOX0

Release Release 10 · sc2kfix/sc2kfix Soliloquy Yeah, I know, I said Release 10 would be out three months ago. I also said six months ago that Release 10 would have a full modding framework, but that's pushed out to Release 11, because...

Do you like SimCity 2000? So do we! I'm pleased to announce that the tenth major release of sc2kfix is available with a whole host of new features and bugfixes, including FluidSynth MIDI output, SCURK functionality on Windows 11, preliminary modding support, and much more: github.com/sc2kfix/sc2k...

Comparing the output of my emulator to test data for the jump indirect instruction JMP ($70FF)

I’ve been developing an #emulator for the MOS 6502 and ran into a hardware bug that occurs when a page boundary is crossed during the jump indirect instruction.

Check out my article on the bug & how you can handle it when emulating!

markjames.dev/blog/6502-ju...

#retrocomputing #emulation

Hosting a WebSite on a Disposable Vape Someone's trash is another person's web server.

Hosting a website on a disposable vape bogdanthegeek.github.io/blog/project...

Screenshot of Chippy, a CHIP-8 emulator running the Timendus CHIP-8 Test Suite.

Several months ago, I became interested in emulation, and it led to me developing Chippy, a CHIP-8 emulator written in C#.

Check out the source code on GitHub:

github.com/markjamesm/C...

#emulation #softwaredevelopment #programming #chip-8 #chip8