A82: Answers to misc. Q's (and how to crash back to TIOS in Ash)

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A82: Answers to misc. Q's (and how to crash back to TIOS in Ash)


I just got back from a week of skiing in France, and naturally I have some
comments to some of the question which have been asked while I was gone.

Crashing back to Ash / TI-OS :

If you want to crash back to Ash, just do a RET. If you are not sure that
you have pop all the info you have pushed, save the stack pointer in the
beginning of you program (use the code send to this list by Barybary).

IT IS POSSIBLE TO CRASH BACK TO TIOS eventhough some people say that it is
not. It has never been tested and it requires the use of some undocumented
Ash features however the following code should work:

SUB A ; A=0
LD ($8D70),A ; ($8D70) = A = 0
RET

As I said, it has never been tested, but it should work. (This might not
work in future versions of Ash, but they will include another way to do
this (simpler)).

Self-modifying :

Self-modifying code is used a lot in Ti8x shells, since it gives faster
and smaller code, but for some reason it is almost never used in any other
kind of programs. When you first get used to writing this kind of code it
is not harder to write, and it can give a lot better results. I have used
it for some display routines (included in some never released programs),
where it almost halfed the size of the code. So try to thinking of this
when you are coding.

Build in Random function :

Both the build in function and the ones normally used in assembly games
uses an randseed number to generate the next number. As far as I remember
TI has a document descriping the algorithme used on their web site, but I
have not looked for it for a while. I once looked at the source code for
the random function, put it is really complicated.

Dines

BTW thecubic@juno.com wrote:
>Tsk, tsk, Bill Gates is the assembly man... back in '74 he wrote BASIC

Before Bill Gates got a computer he wrote a BASIC interpeter for some old
computer on paper (without the possibility to test it). He later sold it
to a company (it worked the first time !), and then he formed Microsoft.
Most people on this list would not be able to do anything like that.

_______________________________________

Dines Justesen
Email: dines@post1.com or
       c958362@student.dtu.dk
WWW  : http://www.gbar.dtu.dk/~c958362/
_______________________________________
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