A85: Re: RAM FAIL

To: <assembly-85@lists.ticalc.org>
Subject: A85: Re: RAM FAIL
From: "Dines Justesen" <c958362@student.dtu.dk>
Date: Sat, 13 Sep 1997 00:08:34 +0200
Reply-To: assembly-85@lists.ticalc.org
 I have never seen this message, but finding out how it works was actually
pretty simpel (less than 5 mins of work). Almost all the strings used by the
TI85
is stores on page 0, and you can find the strgin which is used at 328B
("RAM",0).
The actual string is printed by the FAIL function which prints an ASCIIZ
string
followed by the work FAIL (You can fins this in TI-ROM). The String is
printed by
the function at 37C78 (see adr 37CAD). This function is a test of the RAM in
the
system, which rewrites all user mem. The function first writes values from
83?? to
FC00 and then reads them again, if one of the values read is wrong the
message
is printed.

Since it is very unlikely that your RAM does not work i assume that the
begining
of the function is not executed. The reason that it is executed is probably
an asm
program which contains an error. Since it is very unlikely that the table at
the end of
page 0 would hole a ponter to the place called, i can only see two ways in
which this
function could get called. The first is that when usgard exits the rompage
is set to
3 and the stach is messed up. The second is that some program messes up the
TI OS input handler data, that causes the change of rompage and the call to
the function.
This seems to be the most likely solution since this explains why it happens
when you
exit the shell. Since when a program messes up the stack it might as well
also ruin
something before the pointer used when executing Usgard.

Dines

-----Original Message-----
From: Michael Pearce <mikep@anet-dfw.com>
To: assembly-85@lists.ticalc.org <assembly-85@lists.ticalc.org>
Date: 12. september 1997 21:40
Subject: A85: RAM FAIL



>Has anyone else ever gotten this error message when programming their
>calculator?  I got this lovely error after exiting Usgard from the
>program i was making.  Big letters on a clear screen, "RAM FAIL".  The
>calculator, while displaying this, had the busy indicator moving.  So
>i took out the batteries, held the ON key for about 5 seconds, put
>them back in and when i turned the calculator back on, the message was
>still there.  I then pressed ON and the calculator froze.  so i
>removed the batteries, pressed ON, put the batteries back in, but the
>calc wouldn't turn on.  So i then took out the back-up and a AAA, and
>the calculator still didn't turn on.  Then i took out the batteries
>out another time, and it turned on just fine.  Anyone know what this
>error message means?  where it is located in ROM, etc.?
>
>-mike
>
>BTW, i have ROM 9.0
>