"R. D. Davis" <rdd(a)rddavis.org> wrote:
> Also, remember that obfuscated code is an art form that should bring
> bonuses and raises to programmers skilled in this art. Besides, a
> programmer who can't read so-called "difficult to read code," with no
> comments, isn't a real programmer. :-)
No comments? I think you're forgetting the potential of comments as
things whose maintenance is a lesser priority and whose relationship
to the code may therefore differ from the reader's expectations.
-Frank McConnell
On Feb 28, 11:04, Andreas Freiherr wrote:
> Pete,
>
> understand or agree with all you say. Except:
>
> > > Yes. But this is neither a typo nor a printing error. If you read
four
> > > blocks of 200(8) _words_ each, starting at zero, you fill exactly
> > > 2000(8) _bytes_, and the next free location is 2000(8). As you state,
> > > the printed version is prepared for conversion to single density (by
> > > clearing the 400 bit in locations 2036 and 2072, right?) by reading
in
> > > four blocks... - So, the reason is somewhat similar to that for the
> > > TS-11.
> >
> > Yes, but if it's single density, which is the only reason you'd read
four
> > sectors, the sectors are 128 bytes [100(8)] not 256, so it's still only
> > 1000(8).
>
> Sure, you need not read four sectors if they are 200 words each, but as
> we noted earlier, the routine will always read these four sectors (so
> you need only change two words in order to switch to single density),
> and if these four sectors happen to be from a double-density RX02, you
> will want to have sufficient room for them.
Er, read the code again. The double-density version only loads 2 sectors,
in *all* the versions I've seen.
40 001122 120427 CMPB R4,#3 ; sectors 1
and 3 get done
40 001124 000003
> I haven't tried: is it possible to get a false error indication while
> you are supposed to wait until the RXV11 has digested parameters like
> sector / track number? From reading the docs, I would assume that the
> only reason for the error bit to come on at this time might be an
> invalid parameter like sector > 26, and in this case, you'll probably
> better abort as well (sure, should not happen during boot...). So why
> not just use this check every time you wait for the controller, once the
> check is in the subroutine anyway?
I haven't tried all the permutations to see what happens if you give
garbage in response to a TR request, but the error only shows up ast the
end in cases I have tried. It's almost impossible to test this by hand, as
the controller doesn't wait forever; you only have a short time to respond
to TR so you can't do it from, say, ODT or an 11/40 switch console.
> But, you're right: savings aren't too extreme with this approach, as the
> sequence BIT-BEQ-BMI takes three words, and a JSR would need two. In
> turn, you need two additional words for a MOV #something,SP plus one for
> the RTS, and there are four places with a BMI, so in total we save four
> words by spending three: makes a total of one word saved. Didn't you say
> something like this before? ;-)
Something like that, yeah ;-)
> Let me continue, and we can open a contest for writing the shortest
> bootstrap! ;-)
I used to do that with all sorts of small assembly-languge routines. My
best was saving 200+ bytes out of 2048, in some Z80 code that one
self-proclaimed expert (not the author) described as "a mastepiece of
conciseness".
--
Pete Peter Turnbull
Network Manager
University of York
1. IBM Thinkpad 755c for $12.51
2. Commodore 1084 video monitor for $7
3. hp NetServer 4d/66LM for $33
4. Apple PowerPC 8100/80 tower traded 4 empty PC cases for it.
5. digital VT 420 - 2 for $1 each
6. digital VT 520 - 2 for $1 each
7. WYSE 30+ terminal for $1
8. hp Laserjet IIIp for $1
> From: Joe <rigdonj(a)cfl.rr.com>
> Fred, You've mentioned Xenosoft several times. How about telling us
more
> about it, such as what formats it supports, how much it costs and
wheather
> it supports the Compaticards?
Funny you should mention this. I was looking through an old
book-of-the-month club purchase, "C Programmer's Guide to Serial
Communications," the other night and I found a plug for XenoSoft in it!
Glen
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On February 28, RMChadwick(a)aol.com wrote:
> any body know what the instuction set for the MZ3850 CPU is or better still
> sourse code for the racal RA6790/gm or variant of that rx so i can change the
> cpu for one that works.
I too have a Racal 6790/GM...if you find a solution to the
Unobtainium Processor problem, please let me know. ;-)
-Dave
--
Dave McGuire
St. Petersburg, FL "Less talk. More synthohol." --Lt. Worf
And the "AOS Windows" Disk is NOT MS-Windows... the ONLY reason that any of
the disks say anything about MS is that at that point Xenix was still owned
my Microsoft....
At 03:39 AM 2/28/02 -0600, you wrote:
>On Thu, 28 Feb 2002, Bill Dawson wrote:
>
> > This page says it all:
> >
> > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=2004856941
> >
> > And check out the TOS! ROLF.
>
>Gosh, what an idiot... I might even have a similar set of disks around
>somewhere.
>
>-Toth
Is there info somewhere that shows how symbols are encoded onto paper
tape?
Ideally it would include the actual hole positions like so:
8 4 2 1
A: *
B: *
C: * *
(Note: this is not an actual example but just an example of the format
I'm looking for. Of course.)
Thanks!
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
* Old computing resources for business and academia at www.VintageTech.com *
Once upon a time....
There were a bunch of these in the early hobby channel,
say, around 1981... the seller had complete instructions
for interfacing them, and included some rudimentary code
for using overstrikes to simulate characters bot available
in its 5-level (Murray?) coding scheme.
They were going for $150 at the time, and I still could
kick myself for not grabbing one, they looked pretty cool.
Anyone got a garage full of them?
-dq
> > Peart came in, and while they were impressed with his
> > drumming abilities, they were also thinking, "Hey! This guy can READ!"
Reminds me of the guy who went to an audition and was asked by the band
leader if he could read music.
He replied, "Not enough to screw up my playing."
Also reminds me of "programmers" who can "write code" but seem unable to
read other people's code. Has anyone else had this experience? I run into
this sort of person all the time . . .
Glen
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