Re: A86: Question regarding the 86
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Re: A86: Question regarding the 86
The ram isn't cleared when the batteries get pulled out (for a short time I
assume). However, the registers are reset to 0 so it essentially "resets" by
going back to address $0000 to execute code. You are correct that the rom
keeps a checksum of ram page 2, and that is what enables the crash protection
in programs such as Zac (which does the protection instead of Asmide86). If
the checksum matches, it just returns to the homescreen, but otherwise it
clears the vat (not the rest of ram) and then displays "mem cleared defaults
set".
Chmasc is a little different. It makes a copy of the vat and stores it on
ram page 7 as well a as bit of loader code which you run through that short
basic program. Since the only thing cleared on a real reset is the vat, this
bit of code restores it and thus all your programs magically reappear.
In a message dated 1/11/00 6:31:02 PM Eastern Standard Time,
RoniBarrett@aol.com writes:
> Ok, i think I understand this one...But maybe someone with more solid
> knowledge can answer better. The RAM has a checksum (am i right, i read
this
>
> from the list a lot...) If it is wrong, the RAM is messed up, and the
memory
>
> resets. When the calc is "off" it isnt really off, so it keeps the RAM
> intact. I dont know about
> chsmasc, i use it, but have no clue how it works, but i have read stuff on
> the list a few times about a ROM call that corrects the checksum, so that
> the
> calc thinks it was shut off, and not crashed. Isnt this what the new
AsmIDE
> does when you run compiled programs?
----
Jonah Cohen
<ComAsYuAre@aol.com>
http://linux.hypnotic.org/~jonah/