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Hi,

I've been playing around with the Atmos ROM file (BASIC11b.rom) to test some changes to some of the commands. However when I try and run up Euphoric with the new ROM file it just displays a screen of vertical grey stripes and doesn't get to the Oric welcome screen.

Does Euphoric do any checks on the ROM file when it loads it up?

Cheers
Scott

Hi,

You will probably have to wait until someone with deep knowledge answers, but I guess it does not perform any checking. Else it should at least exit with an error...

The most probable thing is that your modified rom is not booting the Oric properly... Those stripes you see... are they on the Oric screen? Because different roms create different patterns when booting...

IIRC whenever a memory module is broken or something is going wrong in the bootup process, the screen hangs with a funny pattern on screen...

But, as I said, these are just guesses...

From a discussion I had with Fabrice years ago, I recall the screen you see when booting is the memory. It depends on the chips used, or something like that.

In Euphoric, the boot screen is simulated, and you can choose in the INI file between 3 different boot screens. So there's no link with the ROM I guess - especially not on Euphoric anyway.

Hi guys,

Thanks for the prompt replies.

I've been debugging the ROM file and found that during startup it fills all memory locations with hex value 55, including the screen memory.

The binary value of #55 is 1010101 which explains the stripes that I can see. It should then display the 'ORIC EXTENDED BASIC'... message which it currently isn't so I must have accidently changed something in the ROM that is preventing the startup screen from showing although at the moment I'm not sure what that is.

More debugging required.

Cheers
Scott

Oh, I think I was mistaken. I thought you were talking about large stripes that can be seen at the very beginning of Euphoric running, but you were actually talking about the 1-pixel-large stripes that breifly appear when the Oric switches from the boot screen to the welcome message, isn't it?

If so, I suspect something wrong with the ROM, too - but I'm no expert.

Sorry Symoon, i didn't give a very good explanation.

I do get the big white lines/blocks that appear at the very beginning.

Hopefully I'll get sometime over the weekend to debug the ROM and track down what's going on.

Cheers
Scott

check for jumps (jsr/jmp) into your modified routines,

it may be jumping into a routine you changed but *not* jumping into the start but the middle of one.

i'v done that - dirty but saves writing the same code again.

you can also put a breakpoint at the start of the rom (like a jmp on itself), and trace the code using the debugger. Or when it crashes, just press F11 to enter the debugger and check where you are in the code, may help finding what's wrong based on the crash adress.

Hi guys,

I've finally solved the problem with the ROM file.

Turns out that the assembler I was using was at fault. The last byte of the ROM should have been #02 but the assembler wasn't writing the last byte so it had a default value of #FF instead.

Unfortunately the last two bytes in the ROM are the IRQ vector address (#0244) so this was being set to #FF44.

I amended the assembler code to write all the bytes and the ROM file now works okay.

Thanks to everyone who took the time to response to my request

Cheers
Scott

Is it possible to know which assembler you are using ?
I guess people would be interested to know about the bug if they happen to use the same

Hi,

Just been looking through all my old posts and I realised that I hadn't replied to your message Dbug

I know it's taken a while to reply but in answer to your question, the assembler I was using was one that I had written myself using C# so don't need to worry about anyone else coming across the bug.


Cheers

Not a problem, thanks for explaining