exxos's Atari, Amiga & retro forum

stephen_usher wrote: 04 Oct 2023 14:39 The ET-4000 is all very well for DTP or other such desktop use but let's face it, 99.999% or the time STs will be used for playing games.

There aren't that many games that would run on a 020 anyway. At least that's what I remember from my PAK/68

mfro wrote: 04 Oct 2023 15:24
There aren't that many games that would run on a 020 anyway. At least that's what I remember from my PAK/68

Hmm. I've had a bit of a different experience with my Pak 68/3 board in my STacy. Using P.Pera's HD adapted
games I've found quite a few of my favorites will run okay.

I think I need to go back and dedicate some time to making a list of those adapted games that will and won't
run here on my STacy.

Note to self: Stock up on Soda and chips beforehand... :lol:

Just adding that, after reading stephen_usher's post, it's because
the Pak board uses a specially modified TOS v3.06. That seems to
cause P.Pera's adapted games to "patch" and run as if it's a TTO30,
which works...

I suppose it would be a lot of work and extra (unnecessary to some)
hardware but could a "fall back" compatible mode be added to the
PiSTorm?

Just a thought, ignore if pointless... :)

Darklord wrote: 04 Oct 2023 16:35 I suppose it would be a lot of work and extra (unnecessary to some)
hardware but could a "fall back" compatible mode be added to the
PiSTorm?

Just a thought, ignore if pointless... :)

From the look of the benchmarks the PiStorm's ST-RAM access speed is only about 70% of a 68000 so unless all your code is running in TT-RAM/Alt-RAM and the display isn't in ST-RAM it will be slower than a normal 68000. I think that's why I was told that for games the PiStorm wasn't for me.

From what I remember of the conversation, the difficulty is the 68000 bus arbitration which needs heavy lifting and a fast response and they've not been able to solve that problem at full speed (yet?).

mfro wrote: 04 Oct 2023 15:24 There aren't that many games that would run on a 020 anyway. At least that's what I remember from my PAK/68

The PiStorm can also emulate a native 68000, of course.

stephen_usher wrote: 04 Oct 2023 16:56 From the look of the benchmarks the PiStorm's ST-RAM access speed is only about 70% of a 68000 so unless all your code is running in TT-RAM/Alt-RAM and the display isn't in ST-RAM it will be slower than a normal 68000. I think that's why I was told that for games the PiStorm wasn't for me.

You've a bit behind the state of the art there, Stephen. That was the situation when @dad664npc came on board. It's now capable of full speed ST-RAM access on a Pi4 or overclocked Pi3. Have a look at the comparisons against ST hardware rather than Falcons & TTs.

The breakthrough here is that we're up to 3.7MB/s -- stock speed.




An 020 has a slightly faster execution time so the stats typically are around 112-120% without faster actual memory access.

From what I remember of the conversation, the difficulty is the 68000 bus arbitration which needs heavy lifting and a fast response and they've not been able to solve that problem at full speed (yet?).

No, it was mostly bus error handling, the slightly quicker clock speed and the slightly later arrival of data in the cycle. Bus Arb was a zero-overhead hack. A lot of the overhead in the emulator has been hacked away and Steve's added a load of cool extra features too.

BW

Back here viewtopic.php?p=106407#p106407 it shows 116% STram speed.. but it needs to be tested with caches turned off to get the raw access speeds.

This is 'PiStorm chat', is it not? So not total thread derail, but...

Ive just found a RPi 3B v1.2 in a drawer, so was wondering if there was a good (read inexpensive) place to buy a PiStorm?

Or has anyone got a 'spare' they want to bring to the show? (Im guessing the standard Amiga one just needs a re-flash?)

I can join in with the action then. :D

Ok, thats me over and out...continue as you were gentlemen.

:2k2:

An Amiga PiStorm for the A500 is what is needed. I purchased my PiStorms from here - https://www.amigakit.com/pistorm-commod ... rrency=GBP
They are in Wales and very helpful. I suggest you contact them and stipulate you need 374 latches instead of the 373 part.
NOTES
1. I have not tried a Pi3B - is it slower than the 3A+? If it is then wait until you can get yourself a Pi4
2. It seems the 373 parts are working but are an unknown - by that, I mean I have not developed using that part so there is no guarantee emulation would be reliable

The problem with the 3B is that it won't fit on the PiStorm -- the USB and Ethernet ports are too tall.

There are workarounds -- extending the header socket on the PiStorm being the most obvious along with desoldering the ports. Don't be tempted to put put in an extension lead (eg, IDE cable) on, however. The signals are switched at between 100 and 200MHz and Bad Things will happen to your data.

I've had good results with my 373 (latch) based board and less good results with my 374 (flipflop) one, but like @dad664npc says, his dev has all been done with the flipflops, so that's where you'll get the support.

Are you using an STE? There may be another option:

https://github.com/dh219/pistorm/tree/w ... istorm-ste

BW

exxos wrote: 04 Oct 2023 17:17 Back here viewtopic.php?p=106407#p106407 it shows 116% STram speed.. but it needs to be tested with caches turned off to get the raw access speeds.

Yeah, GB6 tests overall performance so the fact it ran from 100MB/s memory and had an instruction cache affects the result.

The 3.7MB/s quoted in memspeed in the same post refers.

BW