construct a simple ALU using 4 given components

Discussion in 'Homework Help' started by cth922, Feb 26, 2013.

  1. cth922

    Thread Starter New Member

    Feb 25, 2013
    Hi guys I'm new to this forum hello all.
    so I'm doing a 100 level simple ALU circuit(2's complement), and I'm on the final step, just to connect 4 components into 1 ALU component. the desired outcome is like this( attached pic 1)

    and I have these 4 components to play with: a 4-bit full adder, CMPL,CP4, and OV.
    CMPL CP4 and OV are made by me, the 4 bit adder is in the software

    here's what these 3 components that I made do:
    CMPL: if cm is 0, show original value of d0d1d2d3, if cm is 1, show d0'd1'd2'd3' (flip all)

    CP4:if all input are 0, eq0=1, if most important digit(a3) is 1(2's comp, means nagative) lt0=1

    OV:where s(3) is the sign bit of the result and a(3) and b(3) are the sign bits of the operands. show if there's overflow or underflow.( simply, show 1 if a3=1 b3=1 and s3=0 or a3=0 b3=0 and s3=1)

    and pic2 is what I got so far, I'm pretty confused about the order, port names, plz help.
  2. WBahn


    Mar 31, 2012
    Please help... what?

    I don't see a question anywhere.

    You've done a pretty nice job of describing what you are trying to do and what you have done -- thank you very much for that, it's surprisingly rare to see.

    But now you just need to finish it off and figure out how to phase a question that gets at the heart of what you are confused or unsure about.