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ROMable SMSQ/E

Anything QL Software or Programming Related.
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Pr0f
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Re: ROMable SMSQ/E

Postby Pr0f » Wed Jan 10, 2018 9:51 pm

you say it wastes either ROM or RAM, but it's probably cheaper - if you are going to implement a large amount of RAM in a system it will probably be DRAM on a simm, and if its on a 68020 or better processor - it will be 32 bits wide - such RAM is relatively cheap and reasonably fast.

ROM isn't cheap or fast, even FLASH, so most likely you might go 16 bits wide, but more likely 8 bits and only use it to get going. If you want to make the OS Rommable, there may be a speed penalty in wait states for doing so. It's something to think about.


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tofro
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Re: ROMable SMSQ/E

Postby tofro » Wed Jan 10, 2018 10:00 pm

With that argumentation, you'll probably want to have a minimum ROM at 0 that could be like 64kBytes and just loads the OS from an SD card or somesuch and is then completely paged out from the address map once the OS is up and running.

Would probably be the cheapest thing and even more flexible than wasting 512kBytes Flash or Eprom for the whole OS. Also would make the upgrade procedure to a new OS way easier.

Tobias


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Peter
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Re: ROMable SMSQ/E

Postby Peter » Wed Jan 10, 2018 10:45 pm

tofro wrote:There absolutely is nothing in SMSQ/E to prevent it being put into a ROM. The Q40 and Q60 used to have SMSQ/E in ROM as long as it fitted into their standard 256kB

It is not quite as simple as that... Q40/Q60 actually mirror ROM at two locations, at $0 so there is a proper reset vector, and at a second address where SMSQ/E continuosly fits.
Also SMSQ/E requires shadow RAM option at $0 and up, so it can do changes at runtime. The Q40/Q60 provide that also.


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Peter
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Re: ROMable SMSQ/E

Postby Peter » Wed Jan 10, 2018 10:51 pm

tofro wrote:Q68 doesn't have ROM at all (at least not in a classic sense), so it is a bit hard on this box to put SMSQ/E into there ;)

The Q68 also has ROM, containing the bootloader. The ROM area has shadow RAM, but the same goes for (S)GC. SMSQ/E won't work otherwise.


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tofro
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Re: ROMable SMSQ/E

Postby tofro » Wed Jan 10, 2018 11:00 pm

Peter wrote:
tofro wrote:Q68 doesn't have ROM at all (at least not in a classic sense), so it is a bit hard on this box to put SMSQ/E into there ;)

The Q68 also has ROM, containing the bootloader. The ROM area has shadow RAM, but the same goes for (S)GC. SMSQ/E won't work otherwise.


That's what I meant with the part in brackets - The ROM doesn't (and I guess wouldn't even be large enough to) hold the OS.

The second part of the statement is actually new to me - I was not aware that SMSQ/E needs to be able to write to the lower memory area once it's up and running. Have you got any details what it is actually trying to do there? I have my doubts. Surely the standard version does load as a binary blob of modules relocating to their intended locations - But once it's done that, does it still try to write itself?

Tobias


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Re: ROMable SMSQ/E

Postby Derek_Stewart » Thu Jan 11, 2018 9:31 am

Hi,

Sorry to throw a spanner in the works, SMSQ/E Gold only works with a Gold or Super Gold Card,

Who is going to write all this.


Regards,

Derek
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Pr0f
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Re: ROMable SMSQ/E

Postby Pr0f » Thu Jan 11, 2018 11:20 am

Something could emulate a gold card or super gold card, then in theory that version of SMSQ/E should work.

It's purely speculation.


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tofro
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Re: ROMable SMSQ/E

Postby tofro » Thu Jan 11, 2018 11:55 am

With the recent availability of re-made GoldCards (and probably SGCs soon), I see more benefit in what you do (working on a more modern QL mainboard). I see no point in re-engineering something that went into a lot of technical compromises for now obsolete ROM copyright and obsolete microdrives.

Tobias


Dave
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Re: ROMable SMSQ/E

Postby Dave » Thu Jan 11, 2018 4:39 pm

It seems at least a little likely that all those Gold Cards and Super Gold Cards will be sitting in attics and closets in a year or two, replaced by something different but much quicker.

Both the projects are using the same target CPU - 68EC030FE40.


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Re: ROMable SMSQ/E

Postby Dave » Thu Jan 11, 2018 4:39 pm

Also, it's polite to see so much informed, instructive and healthy conversation on this topic.



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