Re: A85: x-stat and delete protection
[Prev][Next][Index][Thread]
Re: A85: x-stat and delete protection
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.
>>
>>
>>
>>
>
>
Follow-Ups: