ADVRAM, for what?

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By Manuel

Ascended (18876)

Manuel's picture

28-08-2015, 22:11

We were wondering if it's still useful to have its emulation in openMSX, as there's (in practice) no real hardware corresponding to it.

By l_oliveira

Hero (534)

l_oliveira's picture

29-08-2015, 00:46

At this point ADVRAM would be a moot point... How about we made a V9938(58) clone with built in DMA engine (mimicking the one on the Mega Drive).

That now would be a enormous push on MSX towards better performance.
Mega Drive uses that DMA to fill the VRAM without need to waste too much processor time with VDP transfers.

By Manuel

Ascended (18876)

Manuel's picture

13-09-2015, 13:14

So, do you guys think we should remove advram emulation?

By Grauw

Ascended (10605)

Grauw's picture

13-09-2015, 14:22

I think so.

By Zilogger

Resident (39)

Zilogger's picture

13-09-2015, 16:00

Manuel,
Did you try the ADVRAM Software on BlueMSX.
You'll see, there are the same results wenn using OpenMSX.
It's standard in BlueMSX as well.
You don't need to change the configuration like OpenMSX.

I tested the 3 ADVRAM programms on my modified NMS8280
and tested it as well in BlueMSX and a configuration in OpenMSX.
ADVRAM is usefull. The only thing is, that you need 130 real to buy a DIY package.
There are no schematics known or even what type of hardware is used.
The only thing is that it works in the memory area &H8000- &HBFFF in slot 0.
And that it is connected to the VRAM.
Theoretical possible, but no proof of existence at all.

By Manuel

Ascended (18876)

Manuel's picture

13-09-2015, 20:21

You're confusing me... You say you have your 8280 modded to have ADVRAM and it works? But then you say "Theoretical possible, but no proof of existance at all..."?

By Zilogger

Resident (39)

Zilogger's picture

13-09-2015, 22:52

No, I've a modified NMS8280, but not with ADVRAM.
I'm studying ADVRAM for years.
And also trying to enhance my MSX with more speed than the existing options.
Z8400PSC10, 7.16 MHz (Z8581PSC10) and extra's for more working speed.
The V9958 is the bottleneck in speed options.
ADVRAM is a speed option.
But with no any information how it's done, it stays a challenge.

By Manuel

Ascended (18876)

Manuel's picture

13-09-2015, 22:59

OK... by the way, are you sure blueMSX supports ADVRAM? I couldn't find anything about it... (also not in the source code).

By mars2000you

Enlighted (6267)

mars2000you's picture

13-09-2015, 23:28

I don't think indeed that ADVRAM has been implemented in blueMSX.

By Zilogger

Resident (39)

Zilogger's picture

13-09-2015, 23:43

With the 3 testprogramms you can test the difference between the results.
Do the same tests in BlueMSX and in OpenMSX with the modified ADVRAM settings in the configuration.
In the testresults i did, there where almost no diffences at all.
Like ADVRAM already exist in BlueMSX.

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