A86: Re: new emulator
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A86: Re: new emulator
hmm... thanks for prompting me to look at my code again - after messing with
TI86Emu for a while, I managed to find the bit of code that's messing my
emulator up. It gets here straight after a keypress...
Around 0x6960, ROM page 0x0a, we see this chunk of code:
6957 IN A,($06)
6959 PUSH AF
695A LD A,$80
695C OUT ($06),A
695E LD A,D
695F LD ($8000),A
6952 POP AF
that's definitely writing to the ROM... (unless bit 7 of port 6 actually
does something... I was under the impression that this bit was ignored, ne?)
My emu crashes at 6960, just as it attempts the write.
I can see TI86Emu going through this bit of code as well, but it ignores the
write, as far as I can tell. Now, my question is: WTF is it doing writing to
the ROM ?!?!?!? That's just going to make my code a lot more complicated...
(I'm not checking whether the mem is writable or not, for speed reasons. I
suppose I could always patch the ROM? What do you guys think?)
> At what address in the ROM does it do this? Some devices will
> use writes to
> ROM as hardware control registers, but the calc doesn't do this.
>
> > Should the ROM (program) be trying to write to the ROM (memory)
> during its
> > execution?
sayoonara!
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