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8088 MPH: We Break All Your Emulators

trixter.oldskool.org

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Re: 8088 MPH: We Break All Your Emulators

#61

Post by skrebbel »

Mithaldu wrote: post #52
kyberias wrote: post #38

These days I find it slightly weird that they don't share the source code of the demos or related tools. Demo scene has this wonderful alpha-male thing going.

Keep in mind that demos are usually released at parties in competitions, and occasionally even rewarded with real value prices.

That's definitely not the reason the source is often not released. Often, these days, it's mostly the fact that the code will probably only build on two computers in the world and documenting/fixing that is way more boring than coding a new demo.

Re: 8088 MPH: We Break All Your Emulators

#62

Post by mikepavone »

mark-r wrote: post #57

Slight technical inaccuracy at the start: the Z80 also required a minimum of 4 clocks for a memory access, it wasn't better than the 8088 in that regard.

Nope. An opcode fetch cycle takes 4 clocks, but a normal read or write is only 3.That's why an instruction like LD a, (hl) takes 7 cycles. I believe the GBZ80 always takes 4, but it's more of a separate 8080 clone that borrows from the Z80 a bit than an actual Z80.

Re: 8088 MPH: We Break All Your Emulators

#63

Post by oldmanjay »

diydsp wrote: post #58
kyberias wrote: post #38

These days I find it slightly weird that they don't share the source code of the demos or related tools. Demo scene has this wonderful alpha-male thing going.

I am sorry for whatever pain you're feeling. I don't feel the ethics of open-source apply here or to any works of art. Programs like Microsoft Word, which have a near-monopoly on the work that literally billions of people do everyday to be productive and feed their families, when not distributed in a free manner, are tools of unjust power. I don't feel this person's expressive work, a lifelong dream with no monetary…

the bizarre condescension in your comment seems utterly unnecessary.

Re: 8088 MPH: We Break All Your Emulators

#64

Post by noswi »

kyberias wrote: post #38

These days I find it slightly weird that they don't share the source code of the demos or related tools. Demo scene has this wonderful alpha-male thing going.

Their culture sure is a bit alien. The authors are boasting about the dosbox they've broken, yet (it looks to me that) not a single bug/crash has been reported.

Edit: happily I'm wrong. Quoting ajenner below, "there are emulators (for other targets) which do emulate NTSC decoding properly, but until I did the research for this demo nobody understood how the CGA card generates composite signals well enough to be emulate it properly. I have some code which I hope to be adding to DOSBox (and any other emulators that want it) soon."

Re: 8088 MPH: We Break All Your Emulators

#65

Post by mark-r »

mikepavone wrote: post #62
mark-r wrote: post #57

Slight technical inaccuracy at the start: the Z80 also required a minimum of 4 clocks for a memory access, it wasn't better than the 8088 in that regard.

Nope. An opcode fetch cycle takes 4 clocks, but a normal read or write is only 3.That's why an instruction like LD a, (hl) takes 7 cycles. I believe the GBZ80 always takes 4, but it's more of a separate 8080 clone that borrows from the Z80 a bit than an actual Z80.

Thanks for the correction. I can't believe I've had it wrong for so many years.

Re: 8088 MPH: We Break All Your Emulators

#66

Post by ajenner »

kyberias wrote: post #38

These days I find it slightly weird that they don't share the source code of the demos or related tools. Demo scene has this wonderful alpha-male thing going.

I can't speak for the other authors, but I for one plan to release the source code for the parts I wrote (it needs a bit of cleaning up first, though, and I want to get the technical write-ups done first).

Re: 8088 MPH: We Break All Your Emulators

#67

Post by JoshuaR »

boomlinde wrote: post #44
ekianjo wrote: post #8

Earlier quoted context omitted.

> it becomes a read instruction, write data in two straight lines in memory. So basically this kind of hack could not be used for a game, then, where interaction is needed?

I think Wolfenstein 3D compiles column scaling for each texture to speed up column rendering.

The comments in the Wolf3D source implied that the self-compiling raycasting wasn't faster on an 80286 than a conventional BSP tree would have been, and was in fact slower on an 80486 thanks to invalidating the code cache over and over.

Re: 8088 MPH: We Break All Your Emulators

#68

Post by acqq »

ajenner wrote: post #51
Maakuth wrote: post #46

Earlier quoted context omitted.

I bet their color hacks end up doing something weird or possibly nothing with emulators. No idea about the implementation details of any PC emulator, but it sure would be tempting for an emulator to just display the bitmap copied from the emulated machine's display buffer instead of emulating the actual display adapter. Even emulating the adapter wouldn't be enough, I suppose, as the color tricks rely on some uninten…

There are emulators (for other targets) which do emulate NTSC decoding properly, but until I did the research for this demo nobody understood how the CGA card generates composite signals well enough to be emulate it properly. I have some code which I hope to be adding to DOSBox (and any other emulators that want it) soon.

Do you know, how was the video uploaded to the YouTube made, if the emulators don't work? Was it really recorded with the plain camera?

Re: 8088 MPH: We Break All Your Emulators

#69

Post by userbinator »

qrmn wrote: post #53
aerique wrote: post #48

Earlier quoted context omitted.

I'm not aware of the specifics anymore but by using well-placed NOPs when drawing a scanline you could make the borders disappear on the Atari ST thus getting a higher resolution. This was one of the many advantages the Amiga had over the Atari ST: being able to use the whole screen while the ST had a screen like a letterboxed movie except on all four sides of the screen.

Toggling the register to change between 50/60Hz mode at the right time, specifically, could reset the counter in the ST's Video Shifter and trick it to carry on drawing screen when it should have been outputting blank border. Top and bottom borders were however much easier, because you could open them with just one carefully-timed interrupt each (I used Timer-B, which was linked to horizontal blank and counted lines,…

What's old is new again: plenty of lower-end TN LCD panels pull the same colour trickery to fake 8-bit colour from 6-/7- bit panels (or, reportedly, 10-bit deep colour from 8-bit ones in some cases).

That's known as temporal dithering/FRC (http://en.wikipedia.org/wiki/Frame_Rate_Control ). To get the 2 more bits of "fake" colour depth requires a 4-frame cycle, on which you display either the darker or lighter colour in sequences like 0000, 1100, 1110, and 1111. It's a form of PWM and the same technique used to drive those large outdoor graphic LED display signs, although to avoid flickering the frequencies are in the tens of kHz.

Re: 8088 MPH: We Break All Your Emulators

#70

Post by kyberias »

diydsp wrote: post #58
kyberias wrote: post #38

These days I find it slightly weird that they don't share the source code of the demos or related tools. Demo scene has this wonderful alpha-male thing going.

I am sorry for whatever pain you're feeling. I don't feel the ethics of open-source apply here or to any works of art. Programs like Microsoft Word, which have a near-monopoly on the work that literally billions of people do everyday to be productive and feed their families, when not distributed in a free manner, are tools of unjust power. I don't feel this person's expressive work, a lifelong dream with no monetary…

Lol, I don't feel any pain. :)

I can see that my words can be easily interpreted like you did but I was quite literal is stating that the culture is WONDERFUL. I have no hatred against them although I'm definitely an outsider.

Also, I was literal when I referred to the closed source of these creations. I don't demand or expect them to release any source code. I'm merely wondering whether these demos would be MORE interesting with the source code released as well. As always. In 2015 it seems slightly weird that they don't.

To be clear, I definitely share the joy the authors feel accomplishing these feats. Deep respect.

But I don't get your sexism comment. I maintain that the sub-culture involves some behavior that can be described as "alpha-male". Maybe I was inaccurate with the wording. Could have said "competitive" as well.

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