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K

Ken Smith

John B said:
If you think that C++ is bad, just wait until you graduate to Visual
C#.NET!!

Because of the 8.3 file name format Microsoft likes they had to drop the
"J". It is really C#.NJET. or C#.NIET depending on your spoken language.
 
S

Spehro Pefhany

[...]
unsigned int table[256]; /* Usually compilers initialize arrays to 0 */

I can't think of any compiler that initializes. I doubt that any micro
controller ones do.

If we're talking C, all objects with static storage duration *must* be
initialized. I've never seen a compiler that fails to do that.

Yes that is true. The statements after the declare had me thinking of
code within a function. I still hate C BTW.

How do you like C++? ;-) That's the one that's giving me a headache
at the moment.

Well, we all know what a solid piece of code Windows is.

John

http://www.amazon.com/gp/product/1556155514/


Best regards,
Spehro Pefhany
 
J

John Larkin

[...]
unsigned int table[256]; /* Usually compilers initialize arrays to 0 */

I can't think of any compiler that initializes. I doubt that any micro
controller ones do.

If we're talking C, all objects with static storage duration *must* be
initialized. I've never seen a compiler that fails to do that.

Yes that is true. The statements after the declare had me thinking of
code within a function. I still hate C BTW.

How do you like C++? ;-) That's the one that's giving me a headache
at the moment.

Well, we all know what a solid piece of code Windows is.

John

http://www.amazon.com/gp/product/1556155514/


Best regards,
Spehro Pefhany


"Here, from a former Microsoft developer, are super secrets for
developing bug-free C programs. Maguire provides examples of how bugs
are caught at Microsoft (using actual case histories) and shows how
readers can use these proven programming techniques to get products to
market faster."

Thanks! That's hilarious.

New and used, $9. Almost worth a fling.

John
 
D

David Brown

Ken said:
Spehro Pefhany said:
How do you like C++? ;-) That's the one that's giving me a headache
at the moment.

C++ has got to be an April fools day joke that got out of hand. C was the
wrong place to start to try to extend a language to include objects. C
was intended to produce very tight code and be easy to write a compiler
for. The cost was things like not being able to pass arrays and
structures[1]. C++ loses the tightness and ease of compiling and keeps
the inability to pass some things.

[1] In both C and C++ you can tell if the following statement will change
the value of "Suspect" or not without looking in some other file.

SureToChange = FooBar(Suspect);

from rec.humour.funny:
On the 1st of January, 1998, Bjarne Stroustrup gave an interview to the
IEEE's 'Computer' magazine.

Naturally, the editors thought he would be giving a retrospective view
of seven years of object-oriented design, using the language he
created.

By the end of the interview, the interviewer got more than he had
bargained for and, subsequently, the editor decided to suppress its
contents, 'for the good of the industry' but, as with many of these
things, there was a leak.

Here is a complete transcript of what was was said,unedited, and
unrehearsed, so it isn't as neat as planned interviews.

You will find it interesting...
__________________________________________________________________
Interviewer: Well, it's been a few years since you changed the world
of software design, how does it feel, looking back?

Stroustrup: Actually, I was thinking about those days, just before you
arrived. Do you remember? Everyone was writing 'C' and, the trouble
was, they were pretty damn good at it. Universities got pretty good at
teaching it, too. They were turning out competent - I stress the word
'competent' - graduates at a phenomenal rate. That's what caused the
problem.

Interviewer: problem?

Stroustrup: Yes, problem. Remember when everyone wrote Cobol?

Interviewer: Of course, I did too

Stroustrup: Well, in the beginning, these guys were like demi-gods.
Their salaries were high, and they were treated like royalty.

Interviewer: Those were the days, eh?

Stroustrup: Right. So what happened? IBM got sick of it, and
invested millions in training programmers, till they were a dime a
dozen.

Interviewer: That's why I got out. Salaries dropped within a year, to
the point where being a journalist actually paid better.

Stroustrup: Exactly. Well, the same happened with 'C' programmers.

Interviewer: I see, but what's the point?

Stroustrup: Well, one day, when I was sitting in my office, I thought
of this little scheme, which would redress the balance a little. I
thought 'I wonder what would happen, if there were a language so
complicated, so difficult to learn, that nobody would ever be able to
swamp the market with programmers? Actually, I got some of the ideas
from X10, you know, X windows. That was such a bitch of a graphics
system, that it only just ran on those Sun 3/60 things. They had all
the ingredients for what I wanted. A really ridiculously complex
syntax, obscure functions, and pseudo-OO structure. Even now, nobody
writes raw X-windows code. Motif is the only way to go if you want to
retain your sanity.

[NJW Comment: That explains everything. Most of my thesis work was in
raw X-windows. :)]

Interviewer: You're kidding...?

Stroustrup: Not a bit of it. In fact, there was another problem. Unix
was written in 'C', which meant that any 'C' programmer could very
easily become a systems programmer. Remember what a mainframe systems
programmer used to earn?

Interviewer: You bet I do, that's what I used to do.

Stroustrup: OK, so this new language had to divorce itself from Unix,
by hiding all the system calls that bound the two together so nicely.
This would enable guys who only knew about DOS to earn a decent living
too.

Interviewer: I don't believe you said that...

Stroustrup: Well, it's been long enough, now, and I believe most
people have figured out for themselves that C++ is a waste of time but,
I must say, it's taken them a lot longer than I thought it would.

Interviewer: So how exactly did you do it?

Stroustrup: It was only supposed to be a joke, I never thought people
would take the book seriously. Anyone with half a brain can see that
object-oriented programming is counter-intuitive, illogical and
inefficient.

Interviewer: What?

Stroustrup: And as for 're-useable code' - when did you ever hear of a
company re-using its code?

Interviewer: Well, never, actually, but...

Stroustrup: There you are then. Mind you, a few tried, in the early
days. There was this Oregon company - Mentor Graphics, I think they
were called - really caught a cold trying to rewrite everything in C++
in about '90 or '91. I felt sorry for them really, but I thought
people would learn from their mistakes.

Interviewer: Obviously, they didn't?

Stroustrup: Not in the slightest. Trouble is, most companies hush-up
all their major blunders, and explaining a $30 million loss to the
shareholders would have been difficult. Give them their due, though,
they made it work in the end.

Interviewer: They did? Well, there you are then, it proves O-O works.

Stroustrup: Well, almost. The executable was so huge, it took five
minutes to load, on an HP workstation, with 128MB of RAM. Then it ran
like treacle. Actually, I thought this would be a major stumbling-block,
and I'd get found out within a week, but nobody cared. Sun and HP were
only too glad to sell enormously powerful boxes, with huge resources
just to run trivial programs. You know, when we had our first C++
compiler, at AT&T, I compiled 'Hello World', and couldn't believe the
size of the executable. 2.1MB

Interviewer: What? Well, compilers have come a long way, since then.

Stroustrup: They have? Try it on the latest version of g++ - you
won't get much change out of half a megabyte. Also, there are several
quite recent examples for you, from all over the world. British
Telecom had a major disaster on their hands but, luckily, managed to
scrap the whole thing and start again. They were luckier than
Australian Telecom. Now I hear that Siemens is building a dinosaur,
and getting more and more worried as the size of the hardware gets
bigger, to accommodate the executables. Isn't multiple inheritance a
joy?

Interviewer: Yes, but C++ is basically a sound language.

Stroustrup: You really believe that, don't you? Have you ever sat
down and worked on a C++ project? Here's what happens: First, I've
put in enough pitfalls to make sure that only the most trivial projects
will work first time. Take operator overloading. At the end of the
project, almost every module has it, usually, because guys feel they
really should do it, as it was in their training course. The same
operator then means something totally different in every module. Try
pulling that lot together, when you have a hundred or so modules. And
as for data hiding. God, I sometimes can't help laughing when I hear
about the problems companies have making their modules talk to each
other. I think the word 'synergistic' was specially invented to twist
the knife in a project manager's ribs.

Interviewer: I have to say, I'm beginning to be quite appalled at all
this. You say you did it to raise programmers' salaries? That's
obscene.

Stroustrup: Not really. Everyone has a choice. I didn't expect the
thing to get so much out of hand. Anyway, I basically succeeded. C++
is dying off now, but programmers still get high salaries - especially
those poor devils who have to maintain all this crap. You do realise,
it's impossible to maintain a large C++ software module if you didn't
actually write it?

Interviewer: How come?

Stroustrup: You are out of touch, aren't you? Remember the typedef?

Interviewer: Yes, of course.

Stroustrup: Remember how long it took to grope through the header
files only to find that 'RoofRaised' was a double precision number?
Well, imagine how long it takes to find all the implicit typedefs in
all the Classes in a major project.

Interviewer: So how do you reckon you've succeeded?

Stroustrup: Remember the length of the average-sized 'C' project?
About 6 months. Not nearly long enough for a guy with a wife and kids
to earn enough to have a decent standard of living. Take the same
project, design it in C++ and what do you get? I'll tell you. One to
two years. Isn't that great? All that job security, just through one
mistake of judgement. And another thing. The universities haven't
been teaching 'C' for such a long time, there's now a shortage of
decent 'C' programmers. Especially those who know anything about Unix
systems programming. How many guys would know what to do with
'malloc', when they've used 'new' all these years - and never bothered
to check the return code. In fact, most C++ programmers throw away
their return codes. Whatever happened to good ol' '-1'? At least you
knew you had an error, without bogging the thing down in all that
'throw' 'catch' 'try' stuff.

Interviewer: But, surely, inheritance does save a lot of time?

Stroustrup: does it? Have you ever noticed the difference between a
'C' project plan, and a C++ project plan? The planning stage for a C++
project is three times as long. Precisely to make sure that everything
which should be inherited is, and what shouldn't isn't. Then, they
still get it wrong. Whoever heard of memory leaks in a 'C' program?
Now finding them is a major industry. Most companies give up, and send
the product out, knowing it leaks like a sieve, simply to avoid the
expense of tracking them all down.

Interviewer: There are tools...

Stroustrup: Most of which were written in C++.

Interviewer: If we publish this, you'll probably get lynched, you do
realise that?

Stroustrup: I doubt it. As I said, C++ is way past its peak now, and
no company in its right mind would start a C++ project without a pilot
trial. That should convince them that it's the road to disaster. If
not, they deserve all they get. You know, I tried to convince Dennis
Ritchie to rewrite Unix inC++.

Interviewer: Oh my God. What did he say?

Stroustrup: Well, luckily, he has a good sense of humor. I think both
he and Brian figured out what I was doing, in the early days, but never
let on. He said he'd help me write a C++ version of DOS, if I was
interested.

Interviewer: Were you?

Stroustrup: Actually, I did write DOS in C++, I'll give you a demo
when we're through. I have it running on a Sparc 20 in the computer
room. Goes like a rocket on 4 CPU's, and only takes up 70 megs of
disk.

Interviewer: What's it like on a PC?

Stroustrup: Now you're kidding. Haven't you ever seen Windows '95? I
think of that as my biggest success. Nearly blew the game before I was
ready, though.

Interviewer: You know, that idea of a Unix++ has really got me
thinking. Somewhere out there, there's a guy going to try it.

Stroustrup: Not after they read this interview.

Interviewer: I'm sorry, but I don't see us being able to publish any
of this.

Stroustrup: But it's the story of the century. I only want to be
remembered by my fellow programmers, for what I've done for them. You
know how much a C++ guy can get these days?

Interviewer: Last I heard, a really top guy is worth $70 - $80 an
hour.

Stroustrup: See? And I bet he earns it. Keeping track of all the
gotchas I put into C++ is no easy job. And, as I said before, every
C++ programmer feels bound by some mystic promise to use every damn
element of the language on every project. Actually, that really annoys
me sometimes, even though it serves my original purpose. I almost like
the language after all this time.

Interviewer: You mean you didn't before?

Stroustrup: Hated it. It even looks clumsy, don't you agree? But
when the book royalties started to come in... well, you get the
picture.

Interviewer: Just a minute. What about references? You must admit,
you improved on 'C' pointers.

Stroustrup: Hmm. I've always wondered about that. Originally, I
thought I had. Then, one day I was discussing this with a guy who'd
written C++ from the beginning. He said he could never remember
whether his variables were referenced or dereferenced, so he always
used pointers. He said the little asterisk always reminded him.

Interviewer: Well, at this point, I usually say 'thank you very much'
but it hardly seems adequate.

Stroustrup: Promise me you'll publish this. My conscience is getting
the better of me these days.

Interviewer: I'll let you know, but I think I know what my editor will
say.

Stroustrup: Who'd believe it anyway? Although, can you send me a copy
of that tape?

Interviewer: I can do that.

[Note - for the humor-impaired, not a true story. Making the rounds -
ed.]
 
R

Richard Henry

Spehro Pefhany said:
[...]
unsigned int table[256]; /* Usually compilers initialize arrays to 0 */

I can't think of any compiler that initializes. I doubt that any micro
controller ones do.

If we're talking C, all objects with static storage duration *must* be
initialized. I've never seen a compiler that fails to do that.

Yes that is true. The statements after the declare had me thinking of
code within a function. I still hate C BTW.

How do you like C++? ;-) That's the one that's giving me a headache
at the moment.

Well, we all know what a solid piece of code Windows is.

John

http://www.amazon.com/gp/product/1556155514/

I bought the book a long time ago. He sues lots of Asserts, as I recall.
Not available in my current environment.

One suggestion I followed has to do with the =/== error: "if(x = 1)" is
always true, but "if(x == 1)" may not be. He (and usually I) now write it
"if(1 == x)", since writing "if(1 = x)" will be detected as an error by the
compiler.
 
J

Jim Thompson

I say 'sort of' because the input I have is not true reflected binary
Gray code. The input is a wind direction sensor with eight discrete
positions. They are activated by a small magnet which triggers either
one or two sensors at any time. Thus the eight sensors produce the
following sequence:

00000001
00000011
00000010
00000110
00000100
00001100
00001000
00011000
00010000
00110000
00100000
01100000
01000000
11000000
10000000
10000001

What logic do I need to convert these 16 values to a 4-bit binary
number.

Thanks for your attention.

See...

http://www.analog-innovations.com/SED/WindDirection.pdf

Ken Smith mentioned this approach as a possibility, but didn't
elaborate.

Since "John B" mentioned magnetic switches I took the liberty of
making them pull-down instead of pull-up, so I could use existing
complex functions.

2 1/4 Chips ;-)

Wind Direction Number (DIRWIND) and Pull-Down version correspond to
the original list as follows:

Original DIRWIND Pull-Down

00000001 0 11111110
00000011 1 11111100
00000010 2 11111101
00000110 3 11111001
00000100 4 11111011
00001100 5 11110011
00001000 6 11110111
00011000 7 11100111
00010000 8 11101111
00110000 9 11001111
00100000 10 11011111
01100000 11 10011111
01000000 12 10111111
11000000 13 00111111
10000000 14 01111111
10000001 15 01111110

Hidden in the hierarchy "INDICATOR" is logic that takes "DIRWIND as a
variable and outputs the original table, making simulation testing a
cinch.

...Jim Thompson
 
J

John B

On 17/12/2005 the venerable Jim Thompson etched in runes:

..
..
..
See...

http://www.analog-innovations.com/SED/WindDirection.pdf

Ken Smith mentioned this approach as a possibility, but didn't
elaborate.

Since "John B" mentioned magnetic switches I took the liberty of
making them pull-down instead of pull-up, so I could use existing
complex functions.

2 1/4 Chips ;-)

Wind Direction Number (DIRWIND) and Pull-Down version correspond to
the original list as follows:

Original DIRWIND Pull-Down

00000001 0 11111110
00000011 1 11111100
00000010 2 11111101
00000110 3 11111001
00000100 4 11111011
00001100 5 11110011
00001000 6 11110111
00011000 7 11100111
00010000 8 11101111
00110000 9 11001111
00100000 10 11011111
01100000 11 10011111
01000000 12 10111111
11000000 13 00111111
10000000 14 01111111
10000001 15 01111110

Hidden in the hierarchy "INDICATOR" is logic that takes "DIRWIND as a
variable and outputs the original table, making simulation testing a
cinch.

...Jim Thompson

So we're down to 2 1/4 chips. Congratulations Jim, that's another toast
in the offing.

Looks like I'll have to get down to the local Co-op and restock the
wine cellar. It'll have to be tomorrow as it's 2:30 am here and I'm off
to my bed.

P.S. There are officially still seven days left so Richard can still
get his entry in, although competition is very tight now. >:-}
 
R

Richard Henry

John B said:
On 17/12/2005 the venerable Jim Thompson etched in runes:

.
.
.

So we're down to 2 1/4 chips. Congratulations Jim, that's another toast
in the offing.

Looks like I'll have to get down to the local Co-op and restock the
wine cellar. It'll have to be tomorrow as it's 2:30 am here and I'm off
to my bed.

P.S. There are officially still seven days left so Richard can still
get his entry in, although competition is very tight now. >:-}

My entry has already been taken - a PAL16L8 or similar device appropriately
programmed. I checked prices at Digikey, however, and a single PAL in 1's
is costly these days compared to a handful of 74xx gates. My feeling about
PAL costs is colored by the shoebox of leftover "free" PALS I have
accumulated over the years.
 
J

John B

On 17/12/2005 the venerable Richard Henry etched in runes:

..
..
My entry has already been taken - a PAL16L8 or similar device
appropriately programmed. I checked prices at Digikey, however, and
a single PAL in 1's is costly these days compared to a handful of
74xx gates. My feeling about PAL costs is colored by the shoebox of
leftover "free" PALS I have accumulated over the years.

Just before I retired I cleaned out the back cupboard in the office and
found a box of ECL PAL's from 1989 or thereabouts (can't remember the
part number). I couldn't think what to do with them so they went in the
skip. Pity, because you could have added them to your collection!!
 
R

Rich Grise

My entry has already been taken - a PAL16L8 or similar device appropriately
programmed. I checked prices at Digikey, however, and a single PAL in 1's
is costly these days compared to a handful of 74xx gates. My feeling about
PAL costs is colored by the shoebox of leftover "free" PALS I have
accumulated over the years.

Well, if John B is doing a one-off, why not program him one and send it
off in an envelope? ;-)

Or would that count as "bribing the judge"? ;-)

Cheers!
Rich
 
R

Rich Grise

Thanks for making the schematic. I like your U3A a lot better than my
idea that used up 3/4ths of a quad NAND.

In the first post where I proposed it. I showed a tables of the outputs
from the parity and priority chips but didn't bother to go look up part
numbers.

Hmmmm... I just did s google on '"parity generator" IC', and this was
the first hit:
http://www.kingswood-consulting.co.uk/giicm/74_29.html#7429833
Looks like a kinda cool chip. In fact, the whole family looks kinda
cool. ;-)

But I know there used to be an MSI parity generator - I think it's
somewhere in the 7418x series, to go with the ALUs.
Ah! Here we go:
http://www.kingswood-consulting.co.uk/giicm/74150.html#74180

And the priority encoder is 74148:
http://www.kingswood-consulting.co.uk/giicm/74100.html#74148

Cheers!
Rich
 
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