Arithmetic and Logic Unit

Arithmetic and Logic Unit
mill

   <processor> (ALU or "mill") The part of the {central
   processing unit} which performs operations such as addition,
   subtraction and multiplication of integers and {bit-wise}
   {AND}, {OR}, {NOT}, {XOR} and other {Boolean} operations.  The
   CPU's instruction decode logic determines which particular
   operation the ALU should perform, the source of the {operands}
   and the destination of the result.

   The width in {bits} of the words which the ALU handles is
   usually the same as that quoted for the processor as a whole
   whereas its external busses may be narrower.  {Floating-point}
   operations are usually done by a separate "{floating-point
   unit}".  Some processors use the ALU for address calculations
   (e.g. incrementing the {program counter}), others have
   separate logic for this.

   (1995-03-24)