How do I design a circuit that can add and subtract two 4-bit two's

complement numbers and indicate overflow?

Can this be built from 1-bit components?

What are the inputs and the outputs?

TIA.

How do I design a circuit that can add and subtract two 4-bit two's

complement numbers and indicate overflow?

Can this be built from 1-bit components?

What are the inputs and the outputs?

TIA.

John E said...

When is the homework due?Quote:> How do I design a circuit that can add and subtract two 4-bit two's

> complement numbers and indicate overflow?

> Can this be built from 1-bit components?

> What are the inputs and the outputs?

Casey

You give me a clue and I'll give you a clue...Quote:> John E said...

> > How do I design a circuit that can add and subtract two 4-bit two's

> > complement numbers and indicate overflow?

> > Can this be built from 1-bit components?

> > What are the inputs and the outputs?

> When is the homework due?

> How do I design a circuit that can add and subtract two 4-bit two's

> complement numbers and indicate overflow?

Yes, with suitable definition of 1-bit components. What do you mean?Quote:> Can this be built from 1-bit components?

If you are asking, it sounds as though you haven't decided what you wantQuote:> What are the inputs and the outputs?

your circuit to do. We can't answer that for you.

I suggest looking up the term "half adder" for information on designing

adder circuits.

Thad

>How do I design a circuit that can add and subtract two 4-bit two's

>complement numbers and indicate overflow?

Yes.Quote:>Can this be built from 1-bit components?

Two 4 bit two's compliment numbers, their sum and the overflow indication.Quote:>What are the inputs and the outputs?

--

(303) 497-1211 P.O. Box 3000

Boulder, CO 80307

Given the question it's clear they want a full 4bit adder based on fullQuote:>> Can this be built from 1-bit components?

[...]

> I suggest looking up the term "half adder" for information on designing

> adder circuits.

1bit elements, not on 1/2 bit adders (which makes sense since you get to

use half as many 1bit elements, so it's half the size, latency, and power

consumption).

Stefan

83837.news.uni-berlin.de:

4 full adders wires in parallel. Now do your own homework.Quote:> How do I design a circuit that can add and subtract two 4-bit two's

> complement numbers and indicate overflow?

> Can this be built from 1-bit components?

> What are the inputs and the outputs?

> TIA.

> >How do I design a circuit that can add and subtract two 4-bit two's

> >complement numbers and indicate overflow?

> By reading your course textbook.

> >Can this be built from 1-bit components?

> Yes.

> >What are the inputs and the outputs?

> Two 4 bit two's compliment numbers, their sum and the overflow indication.

> --

> (303) 497-1211 P.O. Box 3000

> Boulder, CO 80307

Instruments TTL data book, with the gold covers from about 1970 or earlier.

Look up the 7481. Copy to paper. Turn in.

Plan B. Write verilog for function. synthesize. print netlist. turn in.

del cecchi

> How do I design a circuit that can add and subtract two 4-bit two's

> complement numbers and indicate overflow?

> Can this be built from 1-bit components?

> What are the inputs and the outputs?

> TIA.

> >> Can this be built from 1-bit components?

> [...]

> > I suggest looking up the term "half adder" for information on designing

> > adder circuits.

> Given the question it's clear they want a full 4bit adder based on full

> 1bit elements, not on 1/2 bit adders (which makes sense since you get to

> use half as many 1bit elements, so it's half the size, latency, and power

> consumption).

general discussion of adder circuits. Once the OP gets a hit, he should

find lots of info on half adders, full adders, carry circuits, etc., to

keep him entertained for a while.

Thad

That's a great idea. But doesn't he need either 10 bits or 512 entries toQuote:> > How do I design a circuit that can add and subtract two 4-bit two's

> > complement numbers and indicate overflow?

> > Can this be built from 1-bit components?

> > What are the inputs and the outputs?

> > TIA.

> Use a 256 entry ROM with 5-bits words

handle the add/subtract requirement?. Or he could make the 512 entry truth

table and run quine-mcclusky minimization. I'll bet there is one of those

available on the net.

del cecchi

>>>How do I design a circuit that can add and subtract two 4-bit two's

>>>complement numbers and indicate overflow?

>>By reading your course textbook.

>>>Can this be built from 1-bit components?

>>Yes.

>>>What are the inputs and the outputs?

>>Two 4 bit two's compliment numbers, their sum and the overflow indication.

>>--

>>(303) 497-1211 P.O. Box 3000

>>Boulder, CO 80307

> Here is the easy solution: go to the library and find a really old Texas

> Instruments TTL data book, with the gold covers from about 1970 or earlier.

> Look up the 7481. Copy to paper. Turn in.

> Plan B. Write verilog for function. synthesize. print netlist. turn in.

> del cecchi

Delete parts you don't need. Turn in.

Would one half-adder (for the LSB) with three full-adders not be aQuote:> <snip!>

> 4 full adders wires in parallel.

preferable solution as there will be no carry input for the LSB?

OK, sir.Quote:> Now do your own homework.

> > How do I design a circuit that can add and subtract two 4-bit two's

> > complement numbers and indicate overflow?

> I don't know how you do it.

What exactly would be a "normal" definition of 1-bit components? Would thatQuote:> > Can this be built from 1-bit components?

> Yes, with suitable definition of 1-bit components. What do you mean?

typically just mean AND gates, OR gates etc? If so I'm assuming that since

half & full adders consist of such components then the answer to my original

question is obviously 'yes'..?

On Wed, 10 Mar 2004 01:24:44 -0000, the renowned "John E"

>> <snip!>

>> 4 full adders wires in parallel.

>Would one half-adder (for the LSB) with three full-adders not be a

>preferable solution as there will be no carry input for the LSB?

Best regards,

Spehro Pefhany

--

"it's the network..." "The Journey is the reward"

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