FPGA for dummies

[JimS]

"Proper Amiga", "Real Amiga", "True Amiga", "The Real Thing".  Oh wait, that last one is from a Coca Cola commercial.:roflmao:

Why can't the fanatics that try to turn this into a holy religion realize that there is no ONE definition of what a "Real" Amiga is anymore. Not even between the most hard core fanatics can they agree what is accepted as a "Real Amiga" and what is labeled as "Clone", "Emulation", "Copy", "The Evil Destroyer of Amiga", etc.

The problem is that those fanatics have brought this "what is a real Amiga" notion into an argument where it doesn't belong. The original question was whether or not an FPGA implementation was "emulation". I maintain that something like UAE where one computer executes a software program to pretend to be another is "emulation". Replay and Minimig are hardware implementations, same as if you wired one by hand like the Lorraine prototype.
It's got nothing to do with the "realness", "accuracy" "quality" or "amiganess" of the project, simply the underlying technology used to do it.
Sheesh

[NorthWay]

Papper is just emulation of real writing..

I thought the Amiga team used SAGE computers (aka "Agony") ..?

I think you needed a SAGE to bootstrap the dev box?

[NorthWay]

How commodore made AGA is irrelevant, it's how you make something that behaves like AGA that is important.

I knew I shouldn't have taken too many steps at once, so I'll break it down:

Is AGA a "proper Amiga" chipset (feel free to define proper so we don't have to go back on that later)?

[Thorham]

These arguments from the "Faithful" about what is "Real" and what is a form of emulation are so ridiculous and narrow minded (and tiring).

Wrong, it's about the principle of what is an emulation and what isn't.

If you want to follow their dogma to the letter then maybe everything that came after the A1000 should be considered emulation?

Of course not, because emulations and partial replicas are two different things.

Why can't the fanatics that try to turn this into a holy religion realize that there is no ONE definition of what a "Real" Amiga is anymore.

The machines you could buy back in the day are the only Amiga computers. What's so fanatical about that?

I have been using the term Amiga inspired a lot lately, because I think that it fits my interests of all things that have their roots in the original Amiga.

That's the whole point behind the real Amiga debate. Some people want Amiga and some people want Amiga inspired.

Step 1: Synapse.
http://www.gizmag.com/researchers-create-artificial-synapse/18482/
http://www.mit.edu/newsoffice/2011/brain-chip-1115.html

Step 2: Neuron....

And without step 3 it will all do nothing.

I knew I shouldn't have taken too many steps at once, so I'll break it down:

Is AGA a "proper Amiga" chipset (feel free to define proper so we don't have to go back on that later)?

Perhaps it's a partial replica? Doesn't matter, because it was designed and made by the makers of Amiga.

[billt]

And without step 3 it will all do nothing.

Step 3 is profit.

[billt]

realize that there is no ONE definition of what a "Real" Amiga is anymore.

Just a note, I haven't been trying to argue about what is real or fake Amiga. My part in the debate is about what is a real or imaginary circuit implementation. OK, I guess I have asked questions about what or who makes something real instead of a simulation or emulation in a custom chip, and what or who makes the same thing not a simualtion/emulation, but that all links back to trying to understand why one custom chip is a real circuit and another custom chip is a figment of everyone's imagination, which is how some people here feel about it.

[billt]

Perhaps it's a partial replica? Doesn't matter, because it was designed and made by the makers of Amiga.

And the "legitimate" makers of Amiga also made the Walker, which has an FPGA in it. I understand this implements some new "custom chip" because they couldn't afford the megabucks to get an ASIC (custom chip) manufactured. Is Walker a partial replica, a simulator, an emulator, an actual computer, or something else? Or is Walker not legitimate enough for people here to discuss this way?

[freqmax]

Either the logic circuit meets the timing specification or it doesn't ..!

How you accomplish that is irrelevant.

[Forcie]

I am terribly amused by all the logical.. uh.. agility demonstrated in this thread by some people, trying to sidestep all cold hard technical facts to justify some kind of personal religious belief.

Stay vigilant. The vile beast of Emulatioladilodillee-ation might lurk around the corner, corrupting your life into something of the unpure!

[psxphill]

To give you an example, in the 6502 some of the "undefined op-codes" are a result of an incomplete decode PLA. What happens is some internal nets are undefined, and we can tell from the design if they are likely to float in one direction (high or low). Then, we get the same behavior. If it is unpredictable then different 6502 devices will also behave in different ways.

In the 6502 case it is mostly predictable, in other chips there may be other entropy that makes it harder to predict. As soon as you have to work out if they are likely to float in one direction or the other & adjust the VHDL accordingly, then you cannot be using the original circuit 1:1.
 
The side effects of an NMOS circuit are going to be different to that of a CMOS circuit. Even an FPGA & ASIC running from the same VHDL don't necessarily behave the same way due to clock skew.

 
It might meet the same documented ratings for timing etc, but that is meaningless when even trying to simulate something so it behaves exactly the same way when operated out of spec (which often is the case for undocumented side effects).
 
It wouldn't suprise me if you hadn't seen any of these issues on the Amiga, it was a pretty simple design that has had very few exploitable undocumented effects. However there are many other platforms where that is not the case and hopefully you'll get to those eventually.
 
Something like the Z80 R register, which is a read/write random register. However it's not really random because it's the ram refresh register. Loading it repeatedly can cause your memory to not be refreshed, so bits randomly drop out if the memory is not read by the CPU. I'd love to see how an accurate FPGA simulation of that would work.

[psxphill]

I knew I shouldn't have taken too many steps at once, so I'll break it down:
 
Is AGA a "proper Amiga" chipset (feel free to define proper so we don't have to go back on that later)?

I'll try to say this in a way that you might understand.
 
The AGA chips that commodore designed and had manufactured are "proper". Anything you design and manufacture are not the same.
 
For example, this:
 
http://en.wikipedia.org/wiki/File:Generic_Cola_Can_Jewel.jpg
 
is not this:
 
http://en.wikipedia.org/wiki/File:CocaColaBottle_background_free.jpg

[psxphill]

And the "legitimate" makers of Amiga also made the Walker, which has an FPGA in it. I understand this implements some new "custom chip" because they couldn't afford the megabucks to get an ASIC (custom chip) manufactured. Is Walker a partial replica, a simulator, an emulator, an actual computer, or something else? Or is Walker not legitimate enough for people here to discuss this way?

The walker is a walker, it's not an a1200 or an a500.
 
The processor and the graphics and sound chips however are the same ones as used in an a1200 or a4000.
 
Having an FPGA in it seems to be confusing you & I'm beginning to think that you're misunderstanding the concepts on purpose.

[psxphill]

I maintain that something like UAE where one computer executes a software program to pretend to be another is "emulation". R

This is the problem, you maintain that but it's incorrect. You don't need a CPU to emulate something. People emulate other peoples behaviour for instance and there is no CPU involved there.
 
So please find some other way to differentiate between the emulation you like and the emulation you don't like.

[JimS]

This is the problem, you maintain that but it's incorrect. You don't need a CPU to emulate something. People emulate other peoples behaviour for instance and there is no CPU involved there.
 
So please find some other way to differentiate between the emulation you like and the emulation you don't like.

What are you smoking? Did I say anything about liking one over the other? Sounds more like you have the prejudice.

[psxphill]

What are you smoking? Did I say anything about liking one over the other? Sounds more like you have the prejudice.

How does it sound like that? I've said on more than one occassion that I like both. It's obvious from my question that I like both.
 
Only by saying that software is emulation but fpga is not emulation does it sound like prejudice.
 
At least someone gets it:
 
http://www.syntiac.com/fpga64.html
http://www.syntiac.com/chameleon.html

[JimS]

How does it sound like that? I've said on more than one occassion that I like both. It's obvious from my question that I like both.
 
Only by saying that software is emulation but fpga is not emulation does it sound like prejudice.

My only concern is to recognize the different technology in the two approaches. Software emulation is different from FPGA implementation. Has nothing to do with anything other than that. They are both ways to do an Amiga, or other things.  

Suppose for example we were talking about music players... You can have a casette player and a CD player. Both do the same thing, but in fundamentally different ways.