Re: A86: Re: New operating system...
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Re: A86: Re: New operating system...
>writes:
>>everything would be left intact. Actually, now that I think about it,
>>two
>>pages would be required, because the OS uses the fps stack on page
>>1--how'd the 85 get around that???
>
>that's at most about 40 or 50 bytes when an asm program is running,
>including the op stack
>you'd probly only need one page, but you'd most likely have to rebuild
>the vat if you wanted to return to ti's os. keeping the vat valid would
>be hell
>
I didn't mean keep it valid, I meant keep a copy of an essentially "blank"
vat. It would only contain the values at reset plus your OS loader (which
would be swapped back to ram page 0 as if it was the only thing on the
calc).
>>It would also handle power on/off along with APD (while inside the
>>shell),
>>as using the normal methods for power off would disrupt the shell.
>>The stack should start at $ffff and video memory would start somewhere
>>$f000. This would place the stack at the most convient location, and
>>video memory goes isn't important, because it will probably be moved
>
>
>if you're gonna rewrite the interrupt routine (you'd have to), why not
>add built-in grayscale?
>
That's a great idea, but would that limit it a little bit? What if you want
to add page-swapping to the interrupt routine? IMHO, the best solution is
to disable interrupts and let the program install one if it needs it. You
could even write a getkey and include the source with the shell zip for lazy
programmers :)
Always advantages and drawbacks to everything. Is there ever a perfect
solution? Hrmm...
>>The OS should include certain things like block write-back, where a
>>program
>>would set a flag and set two address for the start and ending write
>>back
>>locations. With this method, a program could have a block with high
>>scores
>>and other settings, and only that block would be written back (thus
>>not
>>forcing write-back, allowing most of the program's code to be self
>>modified,
>>yet very easily allowing high scores). It could also be made a call
>>instead
>>of a feature used on program exit.
>
>great idea!
>
>-josh
>
>
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