Re: A83: Shells on the 83+


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Re: A83: Shells on the 83+




Thanks for clearing up the bit about the reallocation, I suspected it worked
that way. I suppose you're that multi-tasking isn't a hugely useful feature
(though it has some uses), but we all felt that way then they'd no need for
anything better than Ion. I want to write a multi-tasking shell because no one
has done it on the 83+ yet. I also think I need to clarify about the flash...
Instead of swapping the programs between Flash and RAM as is usually done, I
want to write a rountine to directly copy the program from the Flash to a
tempory variable in RAM for the course of its execution. This involves no
writes to the Flash, and it has no limit on read cycles.

--Robin Kay--

Scott Dial wrote:

> Robin Kay wrote:
> > will gradually decrease as more people get 83+'s and there are more 83+
>
>   I agree that the 83+ has greater potential than it is being let on to,
> but, as a community, the 83 will be associated with a 83+ for a long
> time to come. The 83 might be phased out, but this generation of user
> will have an 83 already. People will constantly want 83+ = 83. The
> portability will not decrease until the 83 is phased out of the
> community, not out of production...
>
> >      Task Switching - Based on my experience with lightweight
>
>   The allocation of heap for data storage has been around for a while.
> The 68k calcs all deal with memory this way. I beleive this would be
> feasible, but you must take into account that you will have to have
> enough space for every programs heap and unarchiving the program. I
> would say that most programs would be small enough to not have a problem
> with this. I have more of a problem with the need for a task-swapping
> system. What purpose would it serve, other than a nifty feature? And I
> admit that it would be cool, but still, most people can handle quitting
> a program and running another.
>
> >      Event/IPC Model - Since the shell uses the interrupts it should
>
>   To me an event handler is not a library routine that is run after a
> timer resets. A event handler to me would be a interrupt that keep track
> of different events, such as key_down and then called a location that
> was associated with that event. It could be of use, but I lack an
> opinion on this.
>
> >      Virtual Directory Structure - The PDM could be used to store
>
> Again, this is just a nifty feature that would take ram... there is
> nothing wrong with all the programs existing in one "folder". That is
> why it is a module for ion and not built in.
>
> > 83, just using the archive space as a backup storage area. RAM should be
> > used more as temporary storage area and the FLASH-ROM more as the
> > hard-disk.
> [snip]
>
>   I have an 89, and I don't use the flash rom for anything that will be
> moved on and off a lot. I don't like the idea of wearing out the flash
> rom...
>
> [...unsnip]
> > However I still don't understand enough about
> > reallocation to try and write that part of it. Program's origins are set
> > at 9327h, either when a program is run it is copied to that address in
> > memory before it is run or any instructions in the program that use
> > absolute addressing are changed at runtime to reflect it's location in
> > memory.
>
> The way to do this is to set the origin to $0. Every absolute address
> then becomes a offset from the beginning of the program. You could do
> that for any newly compiled program. BUT, you still would have to "walk"
> the program. You'd have to find all the abosulte opcodes and still not
> screw up data, etc.
> Otherwise, you would have to know where every reference is. Or, keep a
> table and change all the absolutes to a macro that referenced the table
> instead instead of absolutely... either way, it is a pain. The z80 lacks
> enough relative opcodes.
>
> --
> Scott "_Wrath_" Dial
> wrath@calc.org
> ICQ#3608935
> TimeCity AI Guy II - www.timecity.org
> Member of TCPA - tcpa.calc.org
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