A hydraulic circuit includes a supply and exhaust valve provides a housing having a tapered passage and a tapered plug rotatable in the passage. The plug is biased into sealing engagement with the passage by a spring assembly acting on an inlet conduit providing a power fluid inlet. Rotation of the plug connects the inlet conduit to one of two housing ports to deliver power fluid to either the rod end or the cylinder end of a fluid motor to either retract and extend the piston rod. The plug also provides two additional independent fluid passages connecting other conduits leading to the motor and sump.