Back

A cycle-accurate IBM PC emulator in your web browser

84 points4 daysmartypc.net
wbhart9 hours ago

I've been using MartyPC for a few years and except for emulating glitches in hardware which depend on the manufacturer, date of manufacture or even temperature, it is getting harder to find cycle accurate tricks that MartyPC can't emulate perfectly (believe me, we've been trying).

The whole thing is a marvel of software engineering!

What is remarkable is that the author (GloriousCow) doesn't complain that people are ripping off his code and ideas, but that more people haven't used his learnings to create other cycle accurate emulators for the PC.

johnklos6 hours ago

Temperature? Really? How does that work?

bonzini5 hours ago

If you program a register at a moment and in a way that causes two signals to "collide", the result effectively depends on transistor behavior. That in turn can be temperature dependent.

For an example on the PC see https://int10h.org/blog/2023/03/cga-6845-crtc-phantom-vsync-...

GloriousCow4 days ago

MartyPC brings cycle-accurate IBM PC emulation to your web browser.

Run Area 5150 at 60fps on your phone!

Almost every feature from the desktop version is present if practical:

- View the realtime state of nearly every component of the system. - View live disassembly of CPU instructions. - Edit registers and memory. - Slow down or speed up the system. - Peek on how games draw their graphics with the Memory Visualizer.

WalterGR4 days ago

Pretty incredible!

I’m on mobile right now so I can only comment on the demo that runs automatically, which I understand isn’t the _point_. :)

More about the demo: https://www.vogons.org/viewtopic.php?t=89435

(For those unfamiliar with “demo” in this context, see https://en.m.wikipedia.org/wiki/Demoscene)

I look forward to checking out the features you mention on a proper computer.

rkagerer5 hours ago

I loved it when the Doom floating head demon guy came up. Right when y'all were about to ask "...but can it run Doom?"

nsxwolf11 hours ago

Can you imagine sending an Area 5150 disk back in time to 1981?

trollbridge8 hours ago

You’d be fussing around trying to find enough RAM expansion cards to get your system to 640K (including hot patching the BIOS since it had a bug that it could only get to 544K).

voidspark7 hours ago

640 KB in 1981 was more expensive than 640 GB today.

SoftTalker8 hours ago

Ought to be enough for anyone.

ForOldHack3 hours ago

That was only the first 64k motherboard. ( Five slots only ). Fixed with the PC that came out less than two years later. My brothers machine only had 384k, and it was more than enough. Only three years after, I built 10Mhz XT w/ a V20 640k running Xenix.

kwertyoowiyop7 hours ago

If I had seen this back in the day, I might have given up on programming out of sheer awe!

dosman338 hours ago

I miss Notacon and Jason Scott's Demoscene parties.

imroot5 hours ago

Some of my best hacker/nerd friends I met at notacon. It had a vibe that no other con I’ve been to has had.

theogravity11 hours ago

That demo was pretty mesmerizing!