slightly optimized movementTick

copied movementTick comments from ball to player and missile

src/emucore/tia/Ball.hxx

@@ -345,21 +345,22 @@ void Ball::movementTick(uInt32 clock, bool hblank)
 {
   myLastMovementTick = myCounter;
 
+  if(isMoving)
+  {
     // Stop movement once the number of clocks according to HMBL is reached
     if (clock == myHmmClocks)
       isMoving = false;
-
+    else
-  if(isMoving)
     {
       // Process the tick if we are in hblank. Otherwise, the tick is either masked
       // by an ordinary tick or merges two consecutive ticks into a single tick (inverted
       // movement clock phase mode).
       if(hblank) tick(false);
-
       // Track a tick outside hblank for later processing
       myInvertedPhaseClock = !hblank;
     }
   }
+}
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Ball::tick(bool isReceivingRegularClock)

src/emucore/tia/Missile.hxx

@@ -143,18 +143,28 @@ class Missile : public Serializable
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Missile::movementTick(uInt8 clock, uInt8 hclock, bool hblank)
 {
-  if(clock == myHmmClocks) isMoving = false;
-
   if(isMoving)
   {
+    // Stop movement once the number of clocks according to HMMx is reached
+    if(clock == myHmmClocks)
+      isMoving = false;
+    else
+    {
+      // Process the tick if we are in hblank. Otherwise, the tick is either masked
+      // by an ordinary tick or merges two consecutive ticks into a single tick (inverted
+      // movement clock phase mode).
       if(hblank) tick(hclock, false);
+      // Track a tick outside hblank for later processing
       myInvertedPhaseClock = !hblank;
     }
   }
+}
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Missile::tick(uInt8 hclock, bool isReceivingMclock)
 {
+  // If we are in inverted movement clock phase mode and a movement tick occurred, it
+  // will supress the tick.
   if(myUseInvertedPhaseClock && myInvertedPhaseClock)
   {
     myInvertedPhaseClock = false;
@@ -165,6 +175,8 @@ void Missile::tick(uInt8 hclock, bool isReceivingMclock)
     myIsRendering &&
     (myRenderCounter >= 0 || (isMoving && isReceivingMclock && myRenderCounter == -1 && myWidth < 4 && ((hclock + 1) % 4 == 3)));
 
+  // Consider enabled status and the signal to determine visibility (as represented
+  // by the collision mask)
   collision = (myIsVisible && myIsEnabled) ? myCollisionMaskEnabled : myCollisionMaskDisabled;
 
   if (myDecodes[myCounter] && !myResmp) {
@@ -174,6 +186,7 @@ void Missile::tick(uInt8 hclock, bool isReceivingMclock)
   } else if (myIsRendering) {
 
       if (myRenderCounter == -1) {
+        // Regular clock pulse during movement -> starfield mode
         if (isMoving && isReceivingMclock) {
           switch ((hclock + 1) % 4) {
             case 3:

src/emucore/tia/Player.hxx

@@ -159,19 +159,28 @@ class Player : public Serializable
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Player::movementTick(uInt32 clock, bool hblank)
 {
-  if (clock == myHmmClocks)
-    isMoving = false;
-
   if(isMoving)
   {
+    // Stop movement once the number of clocks according to HMPx is reached
+    if (clock == myHmmClocks)
+      isMoving = false;
+    else
+    {
+      // Process the tick if we are in hblank. Otherwise, the tick is either masked
+      // by an ordinary tick or merges two consecutive ticks into a single tick (inverted
+      // movement clock phase mode).
       if(hblank) tick();
+      // Track a tick outside hblank for later processing
       myInvertedPhaseClock = !hblank;
     }
   }
+}
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void Player::tick()
 {
+  // If we are in inverted movement clock phase mode and a movement tick occurred, it
+  // will supress the tick.
   if(myUseInvertedPhaseClock && myInvertedPhaseClock)
   {
     myInvertedPhaseClock = false;