From: jdrew@cryo.rain.com (Jim Drew)
Newsgroups: comp.sys.amiga.emulations
Subject: Re: EMPLANT - anyone got it running ?
Date: 21 Nov 92 02:23:18 GMT
Article-I.D.: cryo.jdrew.0jrk
Organization: Cryogenic Software - Portland, OR
X-NewsSoftware: BBX-UMB 0.26 beta (Oct 19 1992)


> >What's JD's setup? Is it and accelerated 2000? A 3000? Have UU
> >seen a 4000? a Resolver? Firecracker or Ham-E ???
> 
> Yes, mine's running on an A2000 with A2630.  Although it required the new
> software update before it started working.  So in effect, it's also true
> that they probably shipped a product that at the time, no one could use.
> 
> I think JD's setup is A2000 with VXL-30.
 
Not true.  The machines that we used consisted of A500's, A1000's, &
A2000's (no A3000's here, hence our A3000 dilema).  We used the VXL-30
mainly as well as the Hurricane and MegaMidget racer.
 
The problem is this:  the MAC II (256K OS) series is not 32 bit clean. 
Just ask A3000 owners how many Euro games crash on their system...same
problem with the emulation.  The MAC II uses the upper 8 bits of a
longword as flags.  So, if a memory location is accessed, it must be in
the 24 bit address region and must ignore the upper byte of the address. 
The MAC II's hardware handles this by masking off the upper 8 bits with
it's PMMU or MMU (depending what system you are running with).  We
*never* noticed a problem because the accelerators that we were using
MIRROR'd the memory throughout the full 32 address range.  So, basically,
if the MAC was writing a byte to $200000 and the flag byte was set to
$F0, then the MAC would really be writing to memory location $F0200000. 
Obviously, this could cause serious problems *if* the memory was not
mirror'd.  This is the case with the GVP accelerators, one that we did
not have for testing purposes.  The solution to this problem was to make
a MMU table that simply mirrors memory whenever our task is running
(hence the fix called 'empfix24.lha').
 
We did not release the product KNOWING this problem existed.  It worked
on all of the machines that we used.  Remember, there is only two people
working on this entire product, and we don't have the financial backing
of MicroSoft to allow us the luxary of one of everything made for the
Amiga.  We also can't trust beta testers (at least not all of them) as we
are suing a company in England for stealing the software/hardware for
Super-Card Ami II (even left my copyright message and my name in the
code).  We did sell our houses and pratically everything else that we own
to get enough capital to produce boards.  The EMPLANT deluxe model costs
us a little over $150 just to make, not including labor.
 
Please believe me that our intentions were honest from the start and have
not changed.  The product worked as far as we knew, there were problems
(which have been corrected), and now it is time to get on with the MAC II
SI/CI/LC support.  I appreciate those of you who believed in the product
and stuck it out with us....someday, this is going to make an
unbelievable book...
 


Jim Drew - Vice President, Utilities Unlimited, Inc.
           1641 McCulloch Blvd. Suite #25-124
           Lake Havasu City, AZ  86403
           (602) 680-9004     (602) 680-9006 FAX    (602) 453-9767 BBS
Newsgroups: comp.sys.amiga.emulations