ARM based Amiga?

[Mrs Beanbag]

@Thorham:

Hang on a minute... first you say Amiga is "hardware (680x0 + chipset)", then you complain that the OS is "stuck in the past!"  With all due respect, the 680x0 and the classic Amiga chipset are obsolete hardware.  Don't get me wrong, I love the classic Amiga, but if you insist that that is what Amiga is and always will be, the Amiga is a relic of the past, a museum piece used only by die-hard hobbyists.  I can sympathise, but this is not a way forwards.

In fact I love the 680x0, and I'm about to code some asm in it this afternoon, but it's possibly the least Amiga thing about the Amiga.  Why?  Because it was a generic part.  It was also in Macs and Megadrives and goodness knows what else.  Even the floppy disk drive was more uniquely Amiga (who else got 880k on their floppy disks?).  The OS and the chipset were specifically Amiga products.  Both of these need updating for the 21st century.

@SamuraiCrow: I'm not talking about having the Bealgeboard and Minimig on the same board - perhaps some kind of serial link could be used at first.  A sort of early proof of concept.

[nicholas]

@Thorham:

Hang on a minute... first you say Amiga is "hardware (680x0 + chipset)", then you complain that the OS is "stuck in the past!"  With all due respect, the 680x0 and the classic Amiga chipset are obsolete hardware.  Don't get me wrong, I love the classic Amiga, but if you insist that that is what Amiga is and always will be, the Amiga is a relic of the past, a museum piece used only by die-hard hobbyists.  I can sympathise, but this is not a way forwards.

In fact I love the 680x0, and I'm about to code some asm in it this afternoon, but it's possibly the least Amiga thing about the Amiga.  Why?  Because it was a generic part.  It was also in Macs and Megadrives and goodness knows what else.  Even the floppy disk drive was more uniquely Amiga (who else got 880k on their floppy disks?).  The OS and the chipset were specifically Amiga products.  Both of these need updating for the 21st century.

@SamuraiCrow: I'm not talking about having the Bealgeboard and Minimig on the same board - perhaps some kind of serial link could be used at first.  A sort of early proof of concept.

What if Commodore Amiga were to fund a port of AROS to the Beagleboard and sell them pre-installed and configured as an "Amiga 300"?

Would people be interested?

[Mrs Beanbag]

@nicholas

The beagleboard has an expansion port. I wonder if a 68k emulator could be installed on it and an interface made to connect it to an A1200's trapdoor expansion port... 600MHz accelerator card for Classic Amigas, anyone?

[nicholas]

@nicholas

The beagleboard has an expansion port. I wonder if a 68k emulator could be installed on it and an interface made to connect it to an A1200's trapdoor expansion port... 600MHz accelerator card for Classic Amigas, anyone?

AROS on Rasberry Pi is what interests me tbh.

[bloodline]

AROS on Rasberry Pi is what interests me tbh.

+1

[matthey]

I disagree about the OS sucking so bad.  It's the compilers that suck.  If we could get an up-to-date compiler for 68k, we could write software in C, C++, and (by extension) PortablE that didn't suck instead of twiddling around in Assembly for our larger apps.  Also, since AROS is written in C we'll need the compilers to work better for that as well.

I agree. AmigaOS looks poor on paper but most of the lacking features are "nice" slow bloat that's not really needed. Compilers (biggest problem is 68k optimizing) are the big limitation to AmigaOS and AROS cumming back to the 68k classic which would unite AROS x86, classic 68k, fpga 68k and probably to a certain extent, UAE. That's the majority of Amiga users.

The reason Exec and the other libraries are stuck in the past is that they were written in 68k Assembly.  That just made them harder to bring into the 21st century when 3.5 and 3.9 were written.

 I don't think 68k assembler is so bad to work with with an assembler programmer that knows what they are doing . An assembler programmer needs to be more organized as there is no structure enforced like in C. A well written assembler program is easier to maintain and enhance than a poorly written C program. The Amiga lacks good compilers and a good source level debugger which would help C programming be easier and faster. I can write a little C code but the Amiga C programming experience is frustrating.

As for the compilers, LLVM will soon be able to use a PBQP register scheduler that can store multiple small variables in one register.  This would improve register loading and make it look more like somebody sat down and hand-assembled the whole thing.  The GCC compiler could do similar things but doesn't because the 68k backend is so antiquated.  Nobody will put the time nor energy into GCC 68k because it's thought to be a dead architecture outside of embedded controller use.

 I doubt you will gain much by using small variables in one register on 68040+ and N68k. The need to work on 32 bit values for efficient pipelining and register forwarding limits how much can be done. The fast bitfield instructions in N68k will allow more data per register as well as helping out GCC which likes to use them indiscriminately. You could store multiple Boolean values as a bit each in 1 register or memory address too. There wouldn't be any more overhead (vs GCC 16 bit BOOL) if the N68k bit instructions were enhanced (but not expanded) to be conditional bit instructions like...

 bseteq #3,d0 ;set bit 3 of register d0 if CC Z flag is set

 It's already easy to test a bit but it's not as easy to set, change or clear a bit based on a condition code. The N68k should be able to do it with predication in the same speed with 1 more word...

 bne .skip
 bset #3,d0
.skip:

 The bne and bset will get combined into a conditional instruction also taking 1 cycle. It's a lot better than the 68060 could do where there would be some missed branches and a branch cache entry.

 The 68k beats ARM hands down. It was a properly designed CISC instruction set with RISC core which ARM evolved into with Thumb-2 but with legacy instruction set growing pains worse than 68k. The 68k is easier to read, more logical and consistent and I think the N68k will beat Thumb-2 in code density once the compilers get good enough .

[Thorham]

@Thorham

The reason Exec and the other libraries are stuck in the past is that they were written in 68k Assembly.  That just made them harder to bring into the 21st century when 3.5 and 3.9 were written.

Or is it just because of the OS design? Just read an old OS book from the '80s. That stuff goes far beyond AOS and much of it isn't particularly hard to implement in 68k.

@Thorham:

Hang on a minute... first you say Amiga is "hardware (680x0 + chipset)", then you complain that the OS is "stuck in the past!"  With all due respect, the 680x0 and the classic Amiga chipset are obsolete hardware.

There's plenty of 'modern' things (read through an OS book, and you'll see why) that can be implemented in an efficient way on lower end 680x0 CPUs (but let's skip the 68000).

Even most of the current GUI features are functionally very simple and efficient to implement. The only thing that will be missing is the current eye candy, and some 3D features, and these aren't needed for a much more up to date user experience.

Don't get me wrong, I love the classic Amiga, but if you insist that that is what Amiga is and always will be, the Amiga is a relic of the past, a museum piece used only by die-hard hobbyists.  I can sympathise, but this is not a way forwards.

A dead platform is never the way forward. The part of the Amiga scene that wants to move forward needs to forget about the Amiga and use alternative platforms. Obviously this has been happening for years already. It's just that people keep holding these systems back by sticking to Amiga OS compatibility (which I find quite ludicrous).

In fact I love the 680x0, and I'm about to code some asm in it this afternoon, but it's possibly the least Amiga thing about the Amiga.

Yep, but it's a damned nice CPU to code for from a programmer perspective.

[CritAnime]

My view on this is that I like the ARM processors. They are power efficient and pretty darn spiffy for the money. I would be happy to see something using one.

[Tripitaka]

 The part of the Amiga scene that wants to move forward needs to forget about the Amiga and use alternative platforms. Obviously this has been happening for years already. It's just that people keep holding these systems back by sticking to Amiga OS compatibility (which I find quite ludicrous).

So then how the hell would it be an Amiga? :/

[persia]

Aye, there's the rub, whilst Mac people have Apple to determine what is and isn't Apple, we don't have a similar thing, we're split into camps.  Why Apple has a vision and direction, where everything is explained and scripted. We have  XMOS because, well, the board's manufacturer stuck it on for a cheap price.  

Once upon a time you dressed so fine
You threw the bums a dime in your prime, didn't you ?
People'd call, say, "Beware doll, you're bound to fall"
You thought they were all kiddin' you
You used to laugh about
Everybody that was hangin' out
Now you don't talk so loud
Now you don't seem so proud
About having to be scrounging for your next meal.

How does it feel
How does it feel
To be without a home
Like a complete unknown
Like a rolling stone ?

You've gone to the finest school all right, Miss Lonely
But you know you only used to get juiced in it
And nobody has ever taught you how to live on the street
And now you find out you're gonna have to get used to it
You said you'd never compromise
With the mystery tramp, but know you realize
He's not selling any alibis
As you stare into the vacuum of his eyes
And say do you want to make a deal?

How does it feel
How does it feel
To be on your own
With no direction home
Like a complete unknown
Like a rolling stone ?
You never turned around to see the frowns on the jugglers and the clowns
When they all come down and did tricks for you
You never understood that it ain't no good
You shouldn't let other people get your kicks for you
You used to ride on the chrome horse with your diplomat
Who carried on his shoulder a Siamese cat
Ain't it hard when you discover that
He really wasn't where it's at
After he took from you everything he could steal.

How does it feel
How does it feel
To be on your own
With no direction home
Like a complete unknown
Like a rolling stone ?

Princess on the steeple and all the pretty people
They're drinkin', thinkin' that they got it made
Exchanging all precious gifts
But you'd better take your diamond ring, you'd better pawn it babe
You used to be so amused
At Napoleon in rags and the language that he used
Go to him now, he calls you, you can't refuse
When you got nothing, you got nothing to lose
You're invisible now, you got no secrets to conceal.

How does it feel
How does it feel
To be on your own
With no direction home
Like a complete unknown
Like a rolling stone ?

Wow, does that describe Amiga or what?

So then how the hell would it be an Amiga? :/

[takemehomegrandma]

So then how the hell would it be an Amiga? :/

I think what he really meant was rather "backwards compatible"?

OS4 developers have been compromising backwards compatible in favor of new ways of doing things since the beginning of their endeavor, that's *one* view of evolution.

MorphOS developers have had Amiga compatibility as a primary design and development goal, and carefully evolved the OS in order to protect this, that's *another* view of evolution.

Then you can have a *clean slate* evolution (or rather "revolution"?), where the OS would look and feel the same, but with focus on backwards compatibility with old Amiga apps completely removed from the picture (The OS would be/feel kind of the same, but only/mostly new applications will work, the rest have to run under UAE or similar). That way you could quite easily migrate to ARM or x86, introduce things like true memory protection, true SMP, true multi-user, etc. Things that aren't really possible in an Amiga context without breaking... well, the "Amiga" part of it...

[Mrs Beanbag]

I don't think it's impossible to have both backwards compatibility AND 21st century functionality.  Intel-based PCs manage it, after all.  You can still install Windows 3.1 on a modern PC, or even DOS.  You can still run software from 1981.  I'll repeat this: all modern PC graphics chips have legacy support for EGA graphics!  And let's face it, the continuous demand for backwards compatibility is the only real reason we're still using x86 chips at all, it's not because there are any inherent advantages to the instruction set.

[takemehomegrandma]

@Mrs Beanbag

No, there are things that are completely impossible to implement in Amiga in a clean way without breaking the Amiga compatibility, but would be totally possible if you would say "fcuk the old, only new stuff from here on" and start with a clean slate, and create a new API that will incorporate functions like these but without the ambition of running old Amiga apps (or system components for that matter).

[Hattig]

If you had the resources to implement a 40nm graphics chip today, you would probably find AGA backwards compatibility would be 1% of the logic squeezed into a spare bit on the die. EGA was probably implementable in under 50000 transistors back in the day (I wouldn't be surprised if it was under 10000), and VGA in 100000. Even low-end GPUs are 100,000,000 now.

[Tripitaka]

I don't think it's impossible to have both backwards compatibility AND 21st century functionality.

With FPGA and UAE around I can't help but agree. The simple fact is of course that if a new Amiga was out tomorrow with very little or no backwards compatibility I would judge it purely on its own merits......
.....don't know what software I would run on it though.

[Tripitaka]

@Mrs Beanbag

No, there are things that are completely impossible to implement in Amiga in a clean way without breaking the Amiga compatibility, but would be totally possible if you would say "fcuk the old, only new stuff from here on" and start with a clean slate, and create a new API that will incorporate functions like these but without the ambition of running old Amiga apps (or system components for that matter).

Ahh... and that then begs the question:

Just what do we accept as "backwards compatibility"?
In the true sense of the term, you are of course correct. To some however (myself included) "invisible emulation" is a better way forward. This allows for a clean slate and my old games and apps.