I wish Chris Domas still did presentations. I believe he was hired by Intel and I would guess that they would have asked him to stop publicly presenting.
Smart hire on their part, but his presentations are legendary to me!
It’s actually a shame that there is no `mov rip, ...` instruction. That would make it truly Turing-complete. ARM has this instruction! (Of course, jmp [...] works just as well, but it isn’t called mov)
Yeah, I remember this. It requires setting up a custom signal handler though. IIRC something similar is used to get system/library calls (which also can’t be expressed purely with mov instructions, normally).
If I recall correctly tom7 had a cute trick to get looping behavior in his ASCII-only compiler for 16-bit Intel (http://tom7.org/abc/) which was to make the program 64KB exactly, such that the program counter just loops around at the end. I suppose that’s another option to get _pure_ mov-only code.
Interactivity was added to QuickTime movies. I think this feature was called “wired actions”. I have no idea how this relates to the HyperCard integration.
Apple didn't make an authoring tool for this feature, but another company did: “LiveStage” by Totally Hip.
> I have no idea how this relates to the HyperCard integration.
As I mentioned, QuickTime Movies were to be the file format for HyperCard 3.0 stacks, with QuickTime the HyperCard 3.0 runtime. The QuickTime team demonstrated it at WWDC in 1996.
> Apple didn't make an authoring tool for this feature, but another company did: “LiveStage” by Totally Hip.
The two most Flash-like tools for authoring QuickTime's interactivity capabilities were LiveStage and Electrifier Pro[1]. Additionally, several other tools (like Adobe GoLive and Terran Cleaner) supported simpler forms of interactivity. I was in Apple evangelism/developer relations then, so I was the person working with QuickTime developers on the Apple side.
I did not understand how mov could be used for comparison. Is a register set to a certain value if the contents are already the same value when it's trying to write?
The native and super inefficient way would be basically the same: write 1 to all addresses greater or equal to X, and 0 to all addresses less than X, then read from address Y and see what you end up with.
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[ 1.4 ms ] story [ 26.6 ms ] thread"The inspiration for the compiler is the paper "mov is Turing-complete", by Stephen Dolan."
Chris Domas' movfuscator: https://github.com/xoreaxeaxeax/movfuscator
Presentation: https://www.youtube.com/watch?v=R7EEoWg6Ekk
Smart hire on their part, but his presentations are legendary to me!
2013: https://news.ycombinator.com/item?id=6309631
(Links are for the curious. Reposts are fine after a year or so: https://news.ycombinator.com/newsfaq.html)
[0] https://github.com/xoreaxeaxeax/movfuscator
If I recall correctly tom7 had a cute trick to get looping behavior in his ASCII-only compiler for 16-bit Intel (http://tom7.org/abc/) which was to make the program 64KB exactly, such that the program counter just loops around at the end. I suppose that’s another option to get _pure_ mov-only code.
[1] https://en.wikipedia.org/wiki/PDP-11_architecture#Addressing...
[1] https://en.wikipedia.org/wiki/HyperCard#HyperCard_3.0
Apple didn't make an authoring tool for this feature, but another company did: “LiveStage” by Totally Hip.
As I mentioned, QuickTime Movies were to be the file format for HyperCard 3.0 stacks, with QuickTime the HyperCard 3.0 runtime. The QuickTime team demonstrated it at WWDC in 1996.
> Apple didn't make an authoring tool for this feature, but another company did: “LiveStage” by Totally Hip.
The two most Flash-like tools for authoring QuickTime's interactivity capabilities were LiveStage and Electrifier Pro[1]. Additionally, several other tools (like Adobe GoLive and Terran Cleaner) supported simpler forms of interactivity. I was in Apple evangelism/developer relations then, so I was the person working with QuickTime developers on the Apple side.
[1] https://www.macworld.com/article/1014980/quicktime.html
If X and Y are equal, then you would have written first 0 and then 1 to the same address, so the final read would give you 1.
If X and Y are different, then you would read back the 0 you wrote to address X.
Now, how would you do greater than / less than comparisons?
Probably a more clever trick out there though.
Put a guard value in address X. Write not-guard value to Y. Read X. If the value you just read wasn't the guard value, then Y was the same as X.
https://github.com/stedolan/jq