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Messages - Prodatron

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Other topics / Re: MSX Computers
« on: 2015.May.25. 21:40:04 »
Have a look here:
MSX computers even have a layer above the usual flexible memory mapping known from EP, PCW, NCxxx etc.
First you select...
- a "primary slot" with port #A8
- or even a "secondary slot" (also called sub-slot) at ram address #ffff
...for every of the four 16K page within the 64K visible RAM area.
Selecting the secondary slot is a little bit weird, as you always have to map the primary slot to #c000-#ffff to be able to select its subslots.
Why "slots"? The MSX has 2 external "expansion ports" (like catridges for game consoles) (and 2 internal ones), and each expansion port can be extended by 4 sub-expansion ports. These are the slots/sub-slots.

A memory expansion is placed inside such a (sub)slot. Let's say you have your memory expansion placed in slot 2, subslot 3. If you want to make it visible for the whole 64K you select slot 2, subslot 3 for each of the four 16K pages.
Now you can use port #FC-#FF for selecting the correct 16K page of the memory expansion for each visible 16K page, as #fc-#ff is always the port where the memory expansion of the current slot can be addressed.
In theory this makes it possible to have 4x4x256x16KB of RAM (=64MB) in the MSX :D Slots 0+1 are usually occupied by internal roms etc, so the maximum would be 32MB in practice.

Hope this helped a little bit?

Yes, this is really great!! :) :)

Programming / Re: SymbOS
« on: 2015.May.21. 18:47:05 »
Yes, it was just an idea from me :) why could write Edoz for a normal 4MHz EP: "Seems better then the MSX"
Because normally with MSX VDP it should be faster, and you mentioned SymOS using advantages of VDP :)
My general experience is, that the MSX with 16 colours has a similiar speed like the CPC and EP with 4 colours. The MSX has to handle the double amount of data, but because of the VDPs blitter you have the same speed at the end.
The speed-up isn't that much if there are a lot of bitmaps which have to be handled, as these usually have to be copied from normal memory by the CPU. So that's probably the reason why the "Columns" game feels faster on the EP compared to the MSX.

Programming / Re: SymbOS
« on: 2015.May.21. 17:09:51 »
Yes, it was me, and you are right :)
The blitter of the VDP9938 can be used for a lot of stuff (drawing horizontal/vertical lines, filling rectangles, scrolling and copying rectangle screen areas from one part to another, fill a rectangle with a bitmap "stream" coming from the CPU [no line jumps are necessary]). SymbOS uses the VDP on the MSX for all this to accelerate the graphic output. Printing texts is done in exactly this way, too. In SymbOS the charset is copied to a hidden area of the VRAM (it is 128K on the MSX2) in all 16 colours. As the VDP allows "xor" operation when pasting one rectangle to a destination in the videoram you can use it to plot chars with any colour combinations.

Programming / Re: SymbOS
« on: 2015.May.21. 16:47:02 »
As we already discussed in Budapest it's really hard to compare :) The MSX screen is larger (in this case it's 27KB), but the MSX has a blitter, and the EP not.

Programming / Re: SymbOS
« on: 2015.May.21. 16:24:44 »
Cool, the EP is running at 4MHz all the time?

So really it was only for forcing purposes :D
Yes, and that worked out perfectly! :D

But some more serious and not so much off-topic: it seems I missed the FPGA-MSX/Network/SymbOS demonstration, all I know that (as far as I could hear) there was some problem to manage to use the Network. What was that exactly?
Network was running fine, at least NSLOOKUP.COM worked in SymShell. But the current version of Telnet ("SymTel") required a hardcompiled DNS-server address, and I didnt find the time to change it for Zozos office router. I am in the middle of developing the Network Daemon, so next year on the meeting it's not a problem :P

@LGB: Your way was the most crazy way ever, how someone FORCED me to port SymbOS on a new platform :shock: :mrgreen:
I couldn't believe it, when you suddenly got a "hack" of SymbOS working on the EP :D So I had no other choice than porting SymbOS to this wonderful Z80 machine in the regular way :D And thanks to the help of you, Zozo and the EP scene it was possible :)

@Zozo: Thanks a lot for the corrections! :)
I will edit it! :)

I am now a regular reader of your blog, SzörG! :)

I posted a short report in the international CPC-Forum:

Programming / Re: SymbOS
« on: 2015.May.19. 00:57:22 »
Regarding the mouse better let's discuss it later when some more important things are finished :P

Yes, we also like it :-)
Technicaly 368 (4 color mode) x 300 possible, but probably at many monitors will be cutted :-) Is possible make setup option for these values?

What is a "save" maximum X-resolution? It would be good to have a fixed value here, as it would speed up low level routines...
Yes, Y can be 300, but I would prefer 270 = 256 (main screen) +14 (task bar) because it makes things easier for the main screen (only 8bit Y values for the low level screen routines)

Programming / Re: SymbOS
« on: 2015.May.19. 00:18:58 »
BTW, as we already discussed before I would like to introduce an extended EP version with a screen resolution of 384x270x4 (or what was the X-maximum?) for systems with more than 128KB :P

Programming / Re: SymbOS
« on: 2015.May.18. 23:59:36 »
Not a problem. It just affects the low level routines. Usually they are between #8000 and #bfff, while the visible screen memory is at #c000-#ffff but of course it can be swapped. Usually it's important to have any 16K Ram block at #4000-#7fff and the first 16K of the system at #0000-#3fff, where the kernel is placed.
Anyway this is still easier than a possible Sam Coupe port :)

Programming / Re: SymbOS
« on: 2015.May.18. 23:32:44 »
Before I make the final concept:
Everything looks fine, but would it also possible to have the screen mapped at #c000? :) (just a question, as it would make things easier)

Programming / Re: SymbOS
« on: 2015.May.18. 22:44:16 »
It depends. Usually SymbOS is very flexible with this. Where is the video ram located in the TVC? How is the bitmap mode organsized? Does it encode the colours in bitmap mode in the same way like the EP (and CPC)?
On the CPC the video ram can be placed anywhere in the primary 64K (a little bit like for the EP).

Programming / Re: SymbOS
« on: 2015.May.18. 21:59:59 »
The minimum requirements for the memory mapping would be the Amstrad CPC one:
Here the ram is divided into 64K banks. You have one primary 64K bank (the first 64K) and a number of up to 8 or 15 (576KB is usually the maximum, but there is a mod, where you can have 1024K instead of 576K) secondary 64K banks.
You have the following modi:

- mode 0 ("#c0"): show the primary 64K bank (this is used for executing SymbOS core parts [placed in the primary 64K])
- mode 1 ("#c1"): show the first 48K (at #0000) of the primary 64K bank and the last 16K (at #c000) of a secondary (1-8/15) 64K bank (this is used for accessing GUI data structures of applications by the Desktop Manager without the need to relocate pointers inside these structures)
- mode 2 ("#c2"): show a complete secondary (1-8/15) 64K bank (this is used for executing applications)
- mode 4-7 ("#c4-7"): show the first 16K (at #0000) and the last 32K (at #8000) of the primary 64K bank, and one of the four 16K (at #4000) area of a secondary (1-8/15) 64K bank (this is used for accessing any part of any application by the core parts of SymbOS)

There is even a 3rd mode, but it's not used in SymbOS.
I have no idea, if this would be more simple to implement in hardware or if the Enterprise (=MSX, Amstrad PCW, Amstrad NCxxx) way would be more easy?

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