The adder tag has no wiki summary.
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42 views
Implement using 1 Full adder,1 half adder and no extra gates
y2=x2x1+x0(x2 XOR x1)
y1=x2 XOR x1 XOR x0
y0=x0'
here is my progress
so is it correct ?
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1answer
97 views
Ultra low power adders and multiplier
I am working on a low frequency 30 khz module that needs to have an ultra low power consumption. The problem is the research focuses on improving the performance of the adders and multiplier and ...
-1
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1answer
83 views
What happens to a 32-bit input when a gate will only output 1 bit?
For example, suppose I have a combinational circuit that takes 32 bits as input and outputs 1 bit that is equal to 1 if the 32-bits are equal to 0, and outputs 0 if the 32 bits are anything else. How ...
3
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1answer
577 views
What are carry-lookahead adders and ripple-carry adders?
I see carry-lookahead adders and ripple-carry adders terms being used often. I have no idea what either means (nor the type of architecture they describe).
Can someone please explain what each one ...
5
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2answers
253 views
What is the minimum amount of 1bit Full Adders required to implement the equation 4X + 3Y + 13?
Using 1bit FAs and 0/1 constants only, while X(x1,x2,x3) and ...
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1answer
119 views
Why is carry on for an adder that is simply on? [closed]
I've understood that the behaviour is correct when I make a simple adder:
But why does carry on light up just because I switch on the + operation for my 4-bit system?
...
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0answers
399 views
How to Fix Multiplication Circuit using Logisim
I am designing a circuit that multiplies 2 bit 2's complement numbers.
The circuit uses Full Adder to add and Multiplexer to multiply and ALU for arithmetic.
I need feedback on whether the ...
1
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1answer
365 views
How to multiply using gates?
I need to multiply 2 3bit numbers. I tried that:
but it does not seem to work.
In this example, the output should be 49. so that is that 77?
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0answers
68 views
Choosing among adders
I'm trying to design a 4-bit adder on a transistor level design and was reading up on the best method. 'Best' here in this case refers to the smallest area, lowest delay and best performance. I was ...
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3answers
380 views
Designing a simple ALU
I need to design an ALU with two 8-bit inputs A and B and control inputs x, y, and z that supports the following operations:
...
4
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1answer
338 views
What is wrong with my 2-bit adder?
I attempted to build an 8-bit adder in Logisim by carefully chaining together a half-adder and 7 full adders, all made from basic logic gates. Unfortunately, it produced erroneous results; for ...
4
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4answers
586 views
Test Cases for 16-bit Ripple Carry Adder
I'm working on a lab for a course I have on VHDL, and part of it is to implement an n-bit ripple carry adder and then test it as a 16 bit adder. My problem is that I don't really know HOW to test it, ...
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1answer
2k views
Carry Look ahead adder Propagate & Generate Outputs
I am taking comp architecture course, and we are given a task to write 32 bit look-ahead adder in VHDL. Instructor provided the instruction and diagram.
While reading, Wikipedia article, I stumbled on ...
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1answer
1k views
Determining the truth table and simplifying logic expressions (full adder)
I've been taking an intro computer architecture class and doing some research of my own, I've found the following exercise:
Determine the truth table and simplify the logic expression derived from the ...
1
vote
1answer
352 views
Carry-lookahead adder - what happens to carry bit?
I recreated and trying to understand for the sake of fun and learning the circuit that can be seen here on second page: Link . This is basically a 4-bit carry-lookahead adder, but there is one thing ...
4
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2answers
221 views
How to design system for n bits?
Say I want to design an n-bit system e.g. 256 bits. Can I generalize a 4-bit ALU which I think I know to 256 bits? These are my diagrams.
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2answers
438 views
8 bit octal full adder help
I have this project listen below and im not sure where to start maybe someone can give me a few pointers or perhaps point me in the right direction of starting this?
Thanks!!
Input: A, B = octal ...
2
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2answers
344 views
How does one use both half and full adders together?
I am trying to teach myself the concept of (half and full) adders from Wikipedia and am a bit confused.
Do I need to use both half adders and full adders together for performing multi-bit addition? ...
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1answer
192 views
How do I fit a 2 bit subtractor into its expression?
Regular Full subtractor has the following:
x,y as the inputs
Bin - as the borrow in
Bout - as the borrow out. Bout expression: x'y + x'Bin + yBin
D - difference ...
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1answer
168 views
Is this possible? produce 7 bit sum with one full adder?
i have no idea how to do this all I know is adding 2 bits with one half adder and use bunch of full adder to get a n bit sum...
the original question is below
Design a circuit that adds together 4X ...
3
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2answers
263 views
Why does design_vision compile my carry-lookahead adder into a ripple-carry adder?
At my school we have Synopsis "design_vision" in the computer labs. I don't know how to use any of the features so to me it's just a schematic-drawing tool.
Out of curiosity, I hand-coded in Verilog ...
1
vote
1answer
356 views
Truth Table Accuracy
I made a truth table for this sequential circuit, and I wanted to make sure that it is correct. Is this right? The top left is a full adder, and the top right is a D flip-flop.
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2answers
1k views
Critical path for Carry-Skip adder
Can anybody explain why Carry-Skip adder has the same critical path as regular Carry-Ripple adder. My textbook says that critical path occurs when carry is generated in LSB and then propagating it ...
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2answers
867 views
How to determine if a Carry Look Ahead Adder Overflows
I am implementing a 32 bit CLA Adder like how a 16 bit adder is implemented in Wikipedia
Problem is how do I determine if the block overflows? I will need the carry into bit 32 (which is now in ...
2
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1answer
682 views
Carry look ahead adder/subtractor & Overflow, Negative Bits
I am suppose to design a carry look ahead adder with ...
Input flag bits
E (Enable)
S (Subtraction)
Output
The usual sum & carry out
O (Overflow)
N (Negative)
Z (Zero)
But the question ...
2
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1answer
3k views
How to determine overflow from an adder/subtractor?
I suppose in binary addition (no negative numbers), overflow happens when theres a carry out?
Then for subtractor (2s complement), how do I determine it? From my understanding of my lecture notes, ...
2
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1answer
1k views
How does this carry look ahead block work?
This is a carry look ahead adder :
This adder is known to calculate one or more carry bits before the sum. From the figure we see that carry look ahead block calculates the carry C1,C2,C3,C4 . But ...
