hi there,

I have a question which is in regards to computer system architecture and i am stuck. I need some help and it would be greatly appreciated in producing a circuit of a simple four bit arithmetic unit that can add or subtract two 4 bit binary values. Although only four-bit device is required, the design is expected to be easily extended to any word size.

I am using the digital works application to design this.

thanks in advance

 

hi there,

I have a question which is in regards to computer system architecture and i am stuck. I need some help and it would be greatly appreciated in producing a circuit of a simple four bit arithmetic unit that can add or subtract two 4 bit binary values. Although only four-bit device is required, the design is expected to be easily extended to any word size.

I am using the digital works application to design this.

thanks in advance

Check this website for some information :

http://www.parl.clemson.edu/~dstanzi/201lab/lab5.html

You can extend this 4-bit adder/subtractor by adding more full adder stages and XOR gates.

If you want more information type adder/subtractor circuit in google

 

thanks very much for the help really appreciate it

 

what if i were to want to modify it and add extra circuitry to enable the ALU to perform multiplication and division. i have found it quite difficult finding information on the multiplication and especially the division any help would be greatly appreciated.

 

Here is the Wikipedia article - http://en.wikipedia.org/wiki/Multiplication_ALU.

You are doubtless aware that shifting the binary number left multiplies by 2, or divides by 2 if the shift is to the right.