Making a negative number with ALU

Discussion in 'Homework Help' started by clguy, Dec 12, 2013.

  1. clguy

    Thread Starter New Member

    Sep 26, 2012
    2
    0
    Hello, I am stuck on a problem I am having in class. We are making ALU's and I am supposed to get my value to pass a number and make it a negative. Its an 8 bit number to negative. Example I am passing 5 and 5 as the two numbers...make negative by complementing them (A/A)...then add 1 I am getting B/B...my instructor told me I should be getting A/B...I am lost!! can anyone help...design attached.

    I am to get with this design:
    A+B
    A-B
    A^B
    AorB
    A
    -A

    All of them are working but the -A. Three switches: 1 to choose logic or arithmetic, 1 fpr A and/or B...A, and 1 switch for A+/-B and -A.
     
    Last edited: Dec 12, 2013
  2. WBahn

    Moderator

    Mar 31, 2012
    17,737
    4,789
    Yeah, I'm lost, too.

    Could you try to explain what you are trying to do bit more clearly and provide a complete example both of what you are getting and what you think you should be getting?
     
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