FPGA Replay Board

[psxphill]

That's why programs like Oxypatcher and Cyberpatcher replace instructions before they are trapped.

I'm pretty sure they replace the instructions after they are trapped the first time, not before. Hitting one trapped instruction is not a big deal, it's when you hit one every time through a loop.

[psxphill]

That's how they work which is more prone to problems than trapping while still not full speed. The missing instructions on the 68060 are, by default, trapped every time using the 68060.library.

The solutions are just as good now as they were in the 90's & I don't recall people refusing to buy 68060 boards back then.
Back then you could always recompile your software for 68060 (or even 68000) and then it won't trap, backward compatibility is worth a little slow down.
 
For coldfire a mode that trapped on any instruction that wasn't compatible with 68000 would have been enough, but they didn't care about the market.

[psxphill]

And if a game doesn't want to run correctly on the FPGA Arcade with the 68060 then it could always be run using the soft core CPU.

or possibly WHDLOAD.

[psxphill]

Are you talking about Apples magic pad? If you are i think they look interesting. Do they work on Windows? In my experience touchpads don't work as well on Windows compared to Apples.

I'm assuming something like this...
 
http://www.amazon.com/Wacom-Graphire-Bluetooth-8-Inch-Tablet/dp/B0009DG7KK

[psxphill]

I for one, do not trust the speed assessments given by the simulation software.

Why?

[psxphill]

Because its a simulation and simulations are not real. You can make up 1000 different simulations of something and get 1000 different answers.
 
If they actually knew the answer for a fact then it would be called a Calculation, not a simulation. Right?

There is always a margin of error for maximum clock speed, even with real chips. An 8mhz 68000 doesn't include anything that limits it to exactly that speed for instance. They just picked a round number out of the air and designed it so that the power and heat were roughly within other numbers that they picked out of the air.
 
However if you're talking about how fast a CPU in an FPGA will run at a given clock speed, then the simulation should easily be able to come up with an accurate answer for that.

[psxphill]

So why not just have a faster 68020 CPU in FPGA rather than adding a real 68060 daughtercard?

The same reason you can't just put a 1ghz crystal in your A1200.

[psxphill]

You can put a 1 GHz crystal in your A1200..but buy a fire extinguisher and a miggy replacement first

I doubt it would catch fire, but it won't do what you want. It's likely that it will keep on not doing what you want after you put the 14mhz crystal back. Unless you actually want it to sit there doing nothing, but there are easier ways of achieving that than replacing the crystal.
 
MOVE16 was at least used in some of the CopyMem patches: http://aminet.net/package/util/boot/CopyMem
 
It is theoretically possible to achieve the same compatibility as the real chip, including the FPU and MMU. The speed and size of the FPGA in use will limit the performance. Potentially all the way down to zero if you can't produce a design that fits. Using microcode + a sequencer should allow it to fit, it just won't necessarily be fast enough. There is also the problem that someone has to do it.
 
A sequencer is like a cpu that is designed specifically for doing one task, which is to run the microcode. The microcode is like an emulator that is written for that cpu. As you design both in tandem and can make compromises based on exactly what you need it to do then it works out a lot faster than putting in a general purpose cpu and porting an existing emulator core. But you don't have the luxury of stringing together other peoples work, it's where the glory is though.

[psxphill]

Sure, there are a few patches on the Amiga but MOVE16 is only worthwhile when copying data greater than several kilobytes and the Amiga doesn't copy data that big very often. MOVE16 is barely worth using on a 68k Amiga and I'm the author of CopyMem mentioned above.

Some software uses it and the replay board isn't just an Amiga, it would make sense to reuse the same cpu core for running MacOS or any other operating system.
 
I'm not sure I'd argue that it's not worthwhile if I'd actually released something that used it.

[psxphill]

and another 33% tax to the Exchange Rate Powers That Be.

That isn't how currency exchange rates work. The euro is stronger than the dollar. I imagine that during manufacture mikej is paying for parts etc in different currencies and if the euro wasn't as strong then he'd have to put up the euro price of the replay board.
 
You do pay a small amount for currency conversions, which I agree is a little weird when you're using electronic forms of payment.
 
It's also a little annoying that every day the price you will need to pay will change. The dollar might strengthen against the euro next week or it might weaken.

[psxphill]

@cunnpole
 
This one is only $20.00 for 72 hours. 32GB of space. Writes up to 35 MB/s and reads up to 50 MB/s
 
http://www.newegg.com/Product/Product.aspx?Item=N82E16820178536&nm_mc=EMC-IGNEFL022113&cm_mmc=EMC-IGNEFL022113-_-EMC-022113-Index-_-FlashMemory-_-20178536-L016B
 
20 bucks seems cheap enuff.

sdcard speeds are a bunch of hocum
 
"Speed Classes 2, 4, and 6 assert that the card supports the respective number of megabytes per second as a minimum sustained write speed for a card in a fragmented state. Class 10 asserts that the card supports 10 MB/s as a minimum non-fragmented sequential write speed."
 
So for that card, the most they guarantee is 10MB/S for writes. In some circumstances it might write at 35 MB/s, but it will never write faster than that. While reads will never be faster than 50 MB/s, but they don't guarantee a minimum.
 
A lot of cards have areas that are slower than others, so as long as it's pretty empty then you won't notice it slow down. While sdcards are ok for digital cameras and camcorders where files are written, read and deleted. They aren't so great for computers where you might seek into the middle of a file and overwrite some bytes. This causes flash memory to reallocate blocks, even though the file system might have no fragmentation the underlying flash will be fragmented and there is nothing you can do about it.
 
"UHS Speed Class 1" doesn't seem to mean anything in terms of storage speed, it's purely the interface speed. Kind of like having an ultra scsi floppy drive.

[psxphill]

Thanks I hadn't noticed the dodgy rating fudge for class 10. It seems to be quite difficult to find random read/write benchmarks for sd cards.

Yes it is, although there are some vague recommendations for really expensive sd cards. However I've used identically branded sandisk sd cards that had performance at different ends of the spectrum. The only difference between them was where they were manufactured. So you can't even assume that because someone finds and reviews a card as being good that you'll have the same experience.

[psxphill]

The DRAM controller is designed for the daughterboard and has a 32 bit data path for efficiency. This means a bit of logic an endian-ness fiddling is required to attach it to the 68K softcore.

As long as the ram is only accessed by one cpu then the ram is endian agnostic.

[psxphill]

Oh God, you said the cursed line again! We're doomed!

http://www.youtube.com/watch?v=D5WcDpkKMoc

[psxphill]

You can always wire up a connector onto the spare IO pads if you are handy with a soldering iron. I maybe able to fit a header as an option during ordering.
Will look into this.

Or maybe we need an A4000 to USB keyboard interface.

[psxphill]

Read you PM and you'll have the answer

I'm interested too, I did send a mail or pm to mikej a while back but I don't know if I got on the list.