Instruction-level parallelism - page 3

Suppose we have 9 registers, A,B,C,D,E,F,P,Q, and R, and we want to compute:

   P = A*B ; Q = C+D ; R = E/F.

Compare these two sequences:

   // serial version:  |     // parallel version:
                       |
   A => multiplier     |     A => multiplier
   B => multiplier     |     B => multiplier
   multiplier  => P    |
                       |
   C => adder          |     C => adder
   D => adder          |     D => adder
   adder => Q          |
                       |
   E => divider        |     E => divider
   F => divider        |     F => divider
   divider => R        |
                       |     multiplier => P
                       |     adder      => Q
                       |     divider    => R

The right side sequence has THE EXACT SAME 9 INSTRUCTIONS, MERELY IN A DIFFERENT ORDER! If all three devices take similar times, the right side version will run THREE TIMES FASTER.