Wondering about "Saturating Adders"

Discussion in 'The Projects Forum' started by DylanP, Nov 12, 2014.

  1. DylanP

    Thread Starter New Member

    Nov 12, 2014
    4
    0
    Does anyone know what is the design of a "saturating adder." I was reading a digital design book and I've come across some specific examples online but I was wondering how an n-bit saturating adder works and why is it useful.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,145
    1,791
    A saturating adder is used in digital signal processing applications. It differs from an ordinary 2s complement adder by not allowing overflow or underflow in fixed point operations. Instead it satuarates like an analog adder whose inputs cause the output to go to the supply rails.
    Code (Text):
    1.  
    2. 0x7FF0 + 0x0020 = 0x8010
    3. In a 2s complement adder this would cause what should be a positive result to return a negative number
    4. In a saturating adder
    5. 0x7FF0 + 0x0020 = 0x7FFF
    6. brcause 0x7FFF is the maximum positive or 'saturated' value
    7.  
    Does that clear things up?
     
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