Looking for a memory counter rom (NMS8250) | MSX Resource Center (Page 4/5)

By roadfighter

Champion (461)

15-03-2023, 07:56

Link does work.
Hit the" this" not the "treat"

By Briqunullus

Hero (665)

15-03-2023, 09:43

Or just use the 8245 roms. That works for me in openMSX. Should be the same on real hardware.

By Rataplan

Champion (338)

28-03-2023, 00:09

Glad someone kicked this topic up. So to be clear, on a 8250, what's needed to be done? Are the roms to be split over two eeproms? Like Amiga 1200 kickstart style? Byte 1,3,5,7... in rom1, and 2,4,6,8... in rom2? What two roms to split if that's needed at all?

By Rataplan

Champion (338)

10-04-2023, 11:18

Previous question still stands. But another one: would one have a bios with memory counter that has this awesome effect, posted earlier in this thread? https://m.youtube.com/watch?v=qCJwKXcSDD0&feature=youtu.be

It saves some boottime, and it looks awesome too.

By Briqunullus

Hero (665)

10-04-2023, 13:16

Rataplan wrote:

Glad someone kicked this topic up. So to be clear, on a 8250, what's needed to be done? Are the roms to be split over two eeproms? Like Amiga 1200 kickstart style? Byte 1,3,5,7... in rom1, and 2,4,6,8... in rom2? What two roms to split if that's needed at all?

Well, I did not do this to real hardware. So can't be 100% sure. But this is how I think it could be done.

My customized openMSX config was based on the 8250. But I wanted that memory counter rom. I had read somewhere that the 8245 rom would work. And I modified my config by replacing the subrom. So my config is 8250 main rom and 8245 subrom. And it works fine.

Judging the 8250 board, the subrom is a separate chip. Just burn it with the 8245 subrom (sha1: e7905d16d2ccd57a013c122dc432106cd59ef52c) and see what happens.

Rataplan wrote:

Previous question still stands. But another one: would one have a bios with memory counter that has this awesome effect, posted earlier in this thread? https://m.youtube.com/watch?v=qCJwKXcSDD0&feature=youtu.be

It saves some boottime, and it looks awesome too.

Wow. You should ask Alexey where he got that rom.

By Rataplan

Champion (338)

10-04-2023, 14:31

Well, he calls it Nyyrikki's effect, so maybe he knows things too ;-) I really dig that effect. By the way, I haven't got my 8250 opened atm, and I don't remember from my head, are the roms socketed or am I in for a treat removing the old one

By Wierzbowsky

Guardian (3597)

10-04-2023, 16:03

Briqunullus wrote:

Wow. You should ask Alexey where he got that rom.

I didn't "get" it from somewhere. I composed it myself. I took the original Subrom from a Russian Yamaha YIS-503IIIR, cut out the RAM/VRAM counter code from MSX2+ Subrom, added Nyyrikki's cool effect and inserted a full Testram.rom in order not to waste 16kb of EEPROM. The Testram was patched to be started with a "call" command, it's not the original ROM.

All that required a lot of work and various code placements in unused areas of the second 16kb of the EEPROM. The original Subrom has no free bytes left, so most of the added functionality was placed after the Testram's code. Making such a "cocktail" is quite difficult, but it was a lot of fun.

By Rataplan

Champion (338)

10-04-2023, 16:56

Thanks for elaborating. While I can program, I can't at that level (yet ) @Alexwy , and maybe @Nyyrikki too, how much work is it to apply that effect to a subrom, opposed to the whole ram-check-tool? While I love the idea not to waste any byte, I'd only want to create of have that logo effect. Probably at the 8245 subrom, as that already counts memory as well, and it works in 82xx machines too. So a lot of people could benefit.
I'm willing to investigate how to patch this myself, if I have the code to that effect.

By Wierzbowsky

Guardian (3597)

10-04-2023, 17:36

The effect's code was published by Nyyrikki somewhere on this forum. The problem is - it won't fit into Subrom. You will have to place it somewhere near, preferably in the same subslot. The 8245 has a single 64kb EPROM, it has four 16kb ROMs (BIOS, Basic, Subrom and Diskrom). So, there's zero free space where you could place that effect's code. But maybe I am wrong and I missed a gap. Surprise us!

By Briqunullus

Hero (665)

10-04-2023, 18:21

Nice project indeed. Nyyrikki's part can be found in this thread. Download links still work, except for the ips patch by Philip.

Expanding the subrom to 32K sounds like a great idea. Of course, on real hardware this will require additional modifications to the main board. On openMSX though, it's just a mouseclick away.