Logic Gates and Full Adders

Greetings /prog/

I admittedly haven't been here before, haven't even been to this site but I was lingked here from /g/ so... I was wondering if you could give me a hand with something. I'm a first year computer science student (I know I know there's no jobs and it's a waste of time and whatever) and I was looking through some past papers when I came across a question that has me a little perplexed.

The question asked how I would go about building a denary full adder using these logic gates in order (XNOR,NOR,NOT,NAND). Now logic gates and all that related shit are my arch nemesis but I have no fucking clue how this would even work. Is this somethign that's trivially simple and I'm just being dense or is this as puzzling as it seems?

Sorry if these kind of questions are taboo or whatever, I wasn't willing to lurk for a few months before asking.

>>36,37,39,40
EAT SHIT AND DIE!!!

>>36
Yes it is, the problem being your 'it's someone else's problem' attitude. If you don't know how to write for people, please leave, SHIT TROLL

lol

i dont understand? =/

BUNTH OF FARTITHS IN THITH THREAD

>>43

As a long time lurker of /prog/, I want to dedicate my first post to say GET OUT SHIT TROLL.

>>1 & 10 were the 'Good' posts in this thread....

I guess i don't know how to write for a bunch of $%^$%&%^UR^&I^&OI

>>46
YEAH
Tell them what they really are! Show your true anger!

Nah, that will be all...

I did a basic ternary LSFR loop on paper though =)

>>38
The details of the inside would be nice. I'm still confused as to how this works from a circuitry standpoint.

Do you use a regular full adder 4 times, effectively adding the denary numbers together? How do I make it so that it knows that the number is above 9... like... if...

A and B and C and D
A and B and !C and D
A and !B and C and D

Are all the combinations that I think can give you a binary number equivalent to >9 so would I have to wire it so that those states result in a carry. Also what if what I get results in a carry of greater than 1? Like 1111 + 1111?

Looking back this shit is a hundred times more complicated than anything we were taught or I'm just not understanding something.

1111 + 1111
= 11110
Carry is never greater than 1.

I AM THE KING OF FARTS, BOW DOWN AND SMELL MY HEAVENLY ODORS

I AM THE KING OF FARTS, BOW DOWN AND SMELL MY HEAVENLY ODORS

>>50
Oh... OH! I'm such a howling retard that I was thinking in terms of decimal carries instead of binary carries.

Goddamnit.

>>49
Here's the insides of the BCD full adder: http://pastebin.com/94fRF4hm

First you should understand how multi-digit adders work. They are nothing but a chain of full adders (like in http://en.wikipedia.org/wiki/Adder_%28electronics%29#Ripple_carry_adder ).

A digital comparator shouldn't be very hard to implement. You start with the digit in the most significant position. If the digits of both numbers in that position are equal, you move on to the next one; otherwise, you're done because you can say which one is larger. Your homework is to apply that to make a 4-bit comparator (it's even easier since you're comparing against a constant).

Also, if r=x+y+c where 0≤x≤9 and 0≤y≤9 and 0≤c≤1, then 0≤r≤19.

<DOUBLES!

data:image/svg+xml
What the fuck. Could you be any more perverse?

Here's my version, showing 61+85=146:
http://img839.imageshack.us/img839/6292/bcdadd.png

And for additional perverseness (which happens to be 1/2 the size of yours while being more informative):
http://pastebin.com/1ksMrcxf

/prog/ has become /ee/.

>>56
What program is this?

>>57
programming and ee are intimately related.

>>59
Just like my dick and your anus. Seriously though, I agree.

Thanks so much for helping with this, you are all gentlemen and scholars.

>>56
You could just not be a dick about it, you know.  On the other hand, what program are you using?  Inkscape isn't very appropriate for this kind of job.

>>62
http://www.capilano.com/dww_overview
Yeah, proprietary software, and it sometimes crashes, but I haven't found anything quite as easy to use and portable from the FOSS community (no, I will NOT install 300MB of shitty bloated libraries just to use your 2MB app.)

>>63
Any FOSS Linux-compatible variants (MMLogic is FOSS I think but it only runs on Windows)? I'm too damn lazy to try them out myself.

>>64
http://appdb.winehq.org/objectManager.php?sClass=version&iId=18016
Old enough that it works in WINE. No Verilog or VHDL support though.

There are also a bunch of similarly sluggish and not-so-featureful but portable Java ones like
http://ozark.hendrix.edu/~burch/logisim/

And for *nix only, I used it once, not bad but a bit laggy:
http://www.tkgate.org/

<-Are those doubles I see?
I'M ON A ROLL!

>>64,65
Ah, finally finding out what that program was called after so many years brings a nostalgic tear to my eye, like seeing an old friend -- MMLogic was what pushed me into electronics and programming back when I was six or seven years old. Fuck, I loved it.

 English version drops tonight. Are you ready?

Time enough has passed for a moebeetus thread. heart-stopping images abound. Lay it on thick