Q68 Emulate original QL Keyboard

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Derek_Stewart
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Re: Q68 Emulate original QL Keyboard

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XorA wrote: Fri Jan 19, 2024 3:21 pm
janbredenbeek wrote: Fri Jan 19, 2024 1:56 pm
janbredenbeek wrote: Wed Jan 17, 2024 1:59 pm
I am curious whether this does preserve the 68000 registers or not. If not, it won't be possible to do a full hardware reset with CALL 390 because it expects a magic word in register A5 and boot options in D1. At present, it does a RESET instruction (which sends a reset signal to the hardware but doesn't reset the 68000 itself) followed by a jump to the initial PC vector location. Does the CPU in the Q68 do something similar on a RESET instruction?
Okay, forget that question... I've tested it by replacing the RESET at $190 with MOVE.W $BAD0,$1C024 and CALL 390 works, so the registers appear to be preserved.

Now I need to find out why (re)booting Minerva with SHIFT-F1 sometimes gets you 28MB of RAM instead of 128K, which it cannot handle and crashes sooner or later...
Random numbers in d1 register?
I think I woukd lkke 28Mb rather than 128Kb.

I was looking at the Mjnerva4Q68 Github site, that Minerva can be compiled in a QL environment.

Can Minerva still be started from SMSQ/E on the Q68?


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Derek
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janbredenbeek
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Re: Q68 Emulate original QL Keyboard

Post by janbredenbeek »

XorA wrote: Fri Jan 19, 2024 3:21 pm
Now I need to find out why (re)booting Minerva with SHIFT-F1 sometimes gets you 28MB of RAM instead of 128K, which it cannot handle and crashes sooner or later...
Random numbers in d1 register?
No, I first get 128K but then it immediately reboots with 28MB. Weird...


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XorA
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Re: Q68 Emulate original QL Keyboard

Post by XorA »

https://github.com/SinclairQL/sQLux/com ... 666d0cb148

Was my fix for a very similar problem under emulation.

During boot d1 is compared for an expected value, if its not found it reboots without RAMTOP set and finds all the memory, and not just what its supposed to.


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janbredenbeek
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Re: Q68 Emulate original QL Keyboard

Post by janbredenbeek »

XorA wrote: Fri Jan 19, 2024 7:56 pm https://github.com/SinclairQL/sQLux/com ... 666d0cb148

Was my fix for a very similar problem under emulation.

During boot d1 is compared for an expected value, if its not found it reboots without RAMTOP set and finds all the memory, and not just what its supposed to.
But sQLux skips the entire F1/F2 prompt on startup, Min4Q68 does not.
After some testing I noticed a relationship between the 1.6 extension ROM and this '28MB bug'. This coincides with some lock-ups that Mark has been experiencing with this extension ROM, which didn't occur with 1.5. So it's likely that this bug is in the 1.6 extension ROM, not the Minerva binary itself.


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XorA
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Re: Q68 Emulate original QL Keyboard

Post by XorA »

But sQLux skips the entire F1/F2 prompt on startup, Min4Q68 does not.
It does not, it just runs it so fast that you don't see it. (this is true of uqlx too).


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