@LiveForIt
Quote:Wrong, you'd have to unmap the page containing SysBase->ThisTask (+4092 other bytes of struct ExecBase) instead and use exception handlers to return the required data per core.

Just like there is no SysBase pointer in 0x4 but the zero page is unmapped and an exception handler returns the SysBase pointer if something is accessing 0x4 with a 32 bit read.

No big problem for the zero page, only old m68k code accesses 0x4 to get SysBase, and most only once at program start. For PPC native software it's passed as one of the _start() arguments, or other functions like in libraries, etc., but it's always available without having to access 0x4.
But if you'd unmap a large part of struct ExecBase and use exception handlers instead to return the data you'd get extreme slowdowns, it might even be slower using SMP with 2 cores with such a method than only using a single core

@joerg

Quote:

Easy... set SysBase->ThisTask to 0xdeadcafe or something silly.

put a MMU protection on 0xdeadcfae, the exception routine calls IExec->FindTask(NULL); or something like that.. (might need to find correct the IExec sense that might be a different instance, per core)

"Per-Core Structure: Almost all modern multi-core processors have an MMU integrated into each individual core. This allows each core to independently translate virtual addresses to physical addresses for the thread or process it is currently executing."

So I guess you need to set that exception 4 times, if you have 4 cores..
you might perhaps have a slight different exception per core, that handles instance of IExec..

@LiveForIt
Quote:AddTail() is an exec function, in all versions of AmigaOS.

There are macros for all list functions (or at least were in some old m68k C compiler includes), but software using them instead of the exec functions usually does even much worse things as well, for example using (struct ExecBase *)SysBase->ThisTask instead of IExec->FindTask(NULL), and therefore will never work with SMP.

@OlafS25

How about making some benchmarks using Linux with 1 and several cores? Easily set in VM.

Also this angry tone...

Narcs... make a list of all of their complains and arguments. When you're done you can clearly see that they say "trow that crap away and use somethings else".

Attack the hardware, attack the OS... Yeah that pretty much sums it up! Might just as well get a potato to stare at, maybe that will make them STFU.

When Commodore went under and they celebrated with Doom... They just recently made a comment to a video about a Amiga-game mocking it for having a weak CPU back in the day.

Yeah, you can do that OR you can look at this new FPS that runs on an vanilla A500!

The problem with these discussions is that it's easy to moan over things not being there. Their strategy is to look for faults, they do the same with people, just to get their point through, their way, power.

It's like "no shit, we had no idea! Thank you for enlighten us into this eye-opening world of brand new information!".

Yes you can discuss things but as soon as this bashing everything and moan like a big baby starts, what's the point? To bring everyone down?

Also they've been doing this for 30 years and the Amiga are still going so yeah... it brings everyone down but it doesn't really stop it.

They make everything sound like doom because that's what they want. If there's that much doom then why even use it? Just so you can moan like a baby over what it's not. "This is better, that is better".

One thing that they will *never* understand as well is the why. They aren't passionate about things, nor do they feel love. Actually they can't feel any positive feelings. Anyhow, it's all theoretical according to their limited understanding. So yeah, they are very much involved in bringing it down in the first place but after that it's just "faster, cheaper, better".

All I can say is that there is no place like the Amiga. I can use whatever and it doesn't feel the same. It doesn't feel as good. And that feeling they can never understand, just like love, passion. Because they are hollow inside and feel nothing but they love to bash it to feel powerful. "I won, look at you fools".

And that kind of level when you discuss things isn't a discussion anymore. It's mental abuse to bring you down and give up pretty much. To wear you out.

Just a reminder. It is destructive and doesn't help anyone.

Also this hunt for the latest. Some build a new PC every single month. "Now it's 8k!!!!!!!". I'm still on fullhd and might not get anything better, I don't know because I really don't are that much at the moment.

A narc always hunt material things. To be on top with the latest, "the best". The best is when they can say "look, mine does it faster than yours". While I might argue that mine last longer than yours but that isn't interesting because that doesn't give them this immediate kick of being better that they're constantly after.

You really need to learn to spot them and deal with them. You can discuss in long threads, no problem but there are healthy ways of doing that without it turning into this.

@tao

but if we are talking about 64bit, we don't need to guess. then we must have a sandbox.. so its just over the horizon anyway..

and frankly disabling multitasking to access a public stricture is not good idea... and even worse on SMP system..

Sure maybe solve the messaging API, but AddTail() is a macro, there if you have no function that you retro fit any cache flushes, then the pre-compiled code can't become SMP friendly.

for more info look here, also notice the warnings, and bad advice.

http://amigadev.elowar.com/read/ADCD_ ... cs_3._guide/node01E1.html

you will need to do it on forbid / permit, but that is already pretty bad.

@LiveForIt

Quote:

Of course. Just musing over "how we got here".

Quote:

Thanks for the primer. I'm glad to hear that you're guessing, as hopefully the kernel developers came up with something much more "drop-in". It apparently largely works, too. When the technical writeup finally appears (wiki.amigaos.net ?) I'll be curious to see which solution they chose.

A new Life-of-Tech blog

https://life-of-tech.blogspot.com/2026/02/ayn-odin-2-portal.html

@Tuvok

Hi, yes, the Amiboing high score table should work. Make sure you have the latest version 1.05 from August 1, 2017 installed.
If you have forgotten your password, send us an email at mail@amiboing.de. @imagodespira can reset your password.

@Goos
Thank you so much for this prize and your support. Great stuff.

Any news on Godot for Amiga?

@Tuvok

keep em coming

@OlafS25

Whenever a subject of this nature is brought up in any Amiga forum, I remember all of the doom-and-gloom in the Amiga magazines around 1989-1990 concerning Workbench 2.0 being incompatible with around 60% of the Amiga software at the time. When 2.0 came out, I upgraded. I eventually got a kickstart switcher to run old games. I found the upgrade worth it even though it introduced some incompatibility. If AmigaOS 4.3 or higher breaks compatibility with 68k, there will be workarounds. The new features will be worth the change in my opinion.

@AmigaOldskooler

@Goos

Cool! Thank you!

Does AmiBoing still work for Hi-Score saving? Maybe I lost my password, I can't log in.

@328gts



69043 I'm right behind you! hahaha

@LiveForItQuote:

Interesting video, thanks! I could follow and more or less understand up until AWS Lambda, then I was lost.

@tao

forget DE/AA OS5, it was Amiga Inc project, that is out of the picture..

Not a lot information has shared about sate of SMP in AmigaOS4.1..
so we left guessing...

The fundamental issue for SMP is that core do not see the same content, etch core has unique L1 cache.. when data is shared between the core, the L1 cache, most be synchronized.

https://www.youtube.com/watch?v=r_ZE1XVT8Ao
https://www.youtube.com/watch?v=7yrK_9PderQ

protocol-driven cache coherence, has a lot issues.
1. Lack of Scalability (The "Bus Traffic" Problem)

Snooping Protocol Limits: Common hardware protocols often rely on "snooping" (broadcasting) to inform other cores of changes. This works well for a few cores, but as the number of cores increases, the traffic on the interconnect bus becomes a massive bottleneck, slowing down all processors.

2. High Performance Overhead (Latency and Bandwidth)

Coherence Misses: In a multiprocessor system, if multiple cores constantly write to the same data (false sharing), the hardware must invalidate the cache lines in other cores. This leads to high cache miss rates, which are far more costly than simple memory latency.

3. Inflexibility and Inefficiency

the basic issue you can do protocol-driven cache, but it inefficient, because flushes caches too often, you want the OS to control this..

this comes down to ownership of the data, what core has accessed what data, you don't want the cache to be flushed when its not needed, but you do want to flush it, if you most do so. so keeping tack of what core, did what when. to what data..

"to what data" part is the issue in AmigaOS..

Its up to AmigaOS programs to snoop public lists, because there is lack of locking mechanisms, that specify what data, that is locked, we often have to use the most powerful tool to get ownership, by disabling multitasking, for short periods. Instead of proper lookup functions. Lets say I want to obtain a task or process structure by pid, without blocking the OS, and without risk of reading something that might be freed from memory, without notice. Maybe I want to obtain a msgport by name. There is function called FindPort but does not guarantee ownership or shared lock. The msgport can be deleted without notice. unless you prevent other task form running.

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dup post

@Hans

Your 100% right, the ability for an LLM to generate Linux code is pretty solid. Creating OS 4 code is a struggle for sure. The use of an MCP helps a TON, but, as you point out, most of the examples are outdated and can confuse it.

I have provided updated examples that strongly positively influence the final output.

It's going to be an interesting area over the coming months. I hope this starts the discussion to build a repo of solid code examples so anyone can make good OS 4 code with an LLM.

Cheers,
Bill