Help with 8-bit adder

Discussion in 'Homework Help' started by Aram_Garibyan, Feb 13, 2014.

  1. Aram_Garibyan

    Thread Starter New Member

    Feb 13, 2014
    1
    0
    Hey guys,

    I'm kind of stuck on this homework problem in my Logic Design class and I was wondering if anyone could give a few tips on how to start the solution process. Thanks :)

    A eight bit adder AM8 has a carry input C0 and inputs A7A6A5A4A3A2A1A0 and
    B7B6B5B4B3B2B1B0 and sum output S7S6S5S4S3S2S1S0 and a carry output C8.

    (a) For unsigned addition give the range of values that can be represented by the inputs.

    (b) You have a block AM4 that takes two 4-bit numbers X3X2X1X0 and Y3Y2Y1Y0 and carry input Cin and gives a 4-bit sum output Z3Z2Z1Z0 and carry out Cout. Build the eight bit adder using only AM4 modules. Show all connections and label all inputs and outputs of AM4 and AM8.
     
  2. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    Q1) How many bits do you have in each of your inputs?

    Q2) What is the range of unsigned integers that can be represented by that many bits?

    For the second question, how would you do it by hand?

    Imagine you want to add the values 1234 and 5678, but you can only add two two-digit numbers at a time (though you can include a carry from a previous operation and you can produce a carry for a subsequent operation). How would you do it?
     
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