Re: A85: x-stat and delete protection


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Re: A85: x-stat and delete protection




If you make the first character of any variable a number, or any character
the TI-85 won't let you use in names, it will hide the var.  It won't even
create a problem anywhere.  That's why ! and # are hidden.

At 07:17 PM 3/4/99 -0500, you wrote:
>
>The problem with xStat and yStat is that most of the statistical data is
>stored in the user mem, and even though you can use them as normal vars they
>are not located in the VAT. The only exception to this is xStat and yStat
>which can not be stored in the user mem because the length of both of them
>can change, and they can be very long. I have never tried to hide variables
>my self, but by playing around with the VAT data it might be possible to do
>so. The only thing I can think of is trying to make the var start with a
>wierd char, but what effect that has I dont know. Just do not try to change
>the length of the name to something >8, there is a loop in the ROM which
>will make the calc hang if this is detected (it does a jr $ if length of
>name is >8).
>
>Dines
>----- Original Message -----
>From: Richard Lewis <RichardLewis@CedarCity.net>
>To: <assembly-85@lists.ticalc.org>
>Sent: Wednesday, March 03, 1999 12:37 PM
>Subject: Re: A85: x-stat and delete protection
>
>
>>
>>That won't work.  It's not an area of memory that's special, but the
>>varibales are.  Ans, xStat, yStat, #, and ! all have special status on the
>>85.  They cannot be deleted.  # and ! are invisible, too.
>>
>>If you play with a shell backup, you can delete the shell.  It's located as
>>the very first variable in the RAM.
>>
>>At 10:23 AM 3/3/99 -0500, you wrote:
>>>
>>>> Just a quick question, but one that has the potential to
>>>> be useful.  I know that the x-stat and y-stat lists
>>>> can't be deleted on the TI-85, although you can still
>>>> edit them.  What I want to know is if there is a way to
>>>> add this attribute to other variables, either on a
>>>> computer or through an assembly program.
>>>I'm going out on a limb here, but from what I remember of
>>>hand-hacking the 85 oh so many years ago, xstat and ystat
>>>live very close to the bottom of the variable heap and
>>>probably have priveleged status. It's right up there with
>>>Ans.
>>>
>>>Now, there *might* be some way to do this, if you manage to
>>>push your program to that general area and change something
>>>which defines where the "normal" heap starts. I'd say the
>>>only thing to do is to try it. Dump a backup to your
>>>computer and start twiddling the bits in a hex editor.
>>>
>>>--Jon, N9RUJ jnieho38@calvin.edu www.calvin.edu/~jnieho38
>>>`finger jnieho38@calvin.edu` for geek code block.
>>>
>>>There are only two products to come out of Berkely:
>>>UNIX and LSD.
>>>We don't believe this is a coincidence.
>>>
>>>
>>>
>>>
>>
>>
>
>
>
>



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