diff --git a/src/emucore/Control.cxx b/src/emucore/Control.cxx
index f9400fa3f..93f622933 100644
--- a/src/emucore/Control.cxx
+++ b/src/emucore/Control.cxx
@@ -99,8 +99,7 @@ uInt8 Controller::read()
   if(read(Two))   ioport |= 0x02;
   if(read(Three)) ioport |= 0x04;
   if(read(Four))  ioport |= 0x08;
-
-  return myJack == Left ? (ioport << 4) : ioport;
+  return ioport;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/emucore/Control.hxx b/src/emucore/Control.hxx
index 3acd99cbe..2ae9feaa9 100644
--- a/src/emucore/Control.hxx
+++ b/src/emucore/Control.hxx
@@ -123,12 +123,7 @@ class Controller : public Serializable
 
     /**
       Read the entire state of all digital pins for this controller.
-
-      Note that this method must take into account the location of the
-      pin data in the bitfield, and zero the remaining data:
-
-        Left port : upper 4 bits valid, lower 4 bits zero'ed
-        Right port: lower 4 bits valid, upper 4 bits zero'ed
+      Note that this method must use the lower 4 bits, and zero the upper bits.
 
       @return The state of all digital pins
     */
diff --git a/src/emucore/M6532.cxx b/src/emucore/M6532.cxx
index 6756aa287..7f16c1908 100644
--- a/src/emucore/M6532.cxx
+++ b/src/emucore/M6532.cxx
@@ -119,8 +119,8 @@ uInt8 M6532::peek(uInt16 addr)
   {
     case 0x00:    // SWCHA - Port A I/O Register (Joystick)
     {
-      uInt8 value = myConsole.controller(Controller::Left).read() |
-                    myConsole.controller(Controller::Right).read();
+      uInt8 value = (myConsole.controller(Controller::Left).read() << 4)|
+                     myConsole.controller(Controller::Right).read();
 
       // Each pin is high (1) by default and will only go low (0) if either
       //  (a) External device drives the pin low
diff --git a/src/emucore/TrackBall.cxx b/src/emucore/TrackBall.cxx
index 8d7a5021b..b5deda560 100644
--- a/src/emucore/TrackBall.cxx
+++ b/src/emucore/TrackBall.cxx
@@ -109,7 +109,7 @@ uInt8 TrackBall::read()
   myDigitalPinState[Three] = IOPortA & 0x40;
   myDigitalPinState[Four]  = IOPortA & 0x80;
 
-  return myJack == Left ? IOPortA : (IOPortA >> 4);
+  return (IOPortA >> 4);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -131,9 +131,8 @@ void TrackBall::update()
   if(myTrakBallLinesV == 0) myTrakBallLinesV = 1;
 
   // Get mouse button state
-  myDigitalPinState[Six] =
-    (myEvent.get(Event::MouseButtonLeftValue) == 0) ||
-    (myEvent.get(Event::MouseButtonRightValue) == 0);
+  myDigitalPinState[Six] = (myEvent.get(Event::MouseButtonLeftValue) == 0) &&
+                           (myEvent.get(Event::MouseButtonRightValue) == 0);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/emucore/TrackBall.hxx b/src/emucore/TrackBall.hxx
index cc005360f..a74fc00d7 100644
--- a/src/emucore/TrackBall.hxx
+++ b/src/emucore/TrackBall.hxx
@@ -59,15 +59,7 @@ class TrackBall : public Controller
   public:
     /**
       Read the entire state of all digital pins for this controller.
-
-      Note that this method must take into account the location of the
-      pin data in the bitfield, and zero the remaining data:
-
-        Left port : upper 4 bits valid, lower 4 bits zero'ed
-        Right port: lower 4 bits valid, upper 4 bits zero'ed
-
-      This method completely takes over reading of the port;
-      it doesn't call Controller::read() at all.
+      Note that this method must use the lower 4 bits, and zero the upper bits.
 
       @return The state of all digital pins
     */