Position readout for players.

src/debugger/TIADebug.cxx

@@ -552,10 +552,9 @@ uInt8 TIADebug::posP0(int newVal)
 #if 0 // FIXME
   if(newVal > -1)
     myTIA.myPOSP0 = newVal;
-
-  return myTIA.myPOSP0;
 #endif
-return 0;
+
+  return myTIA.myPlayer0.getPosition();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -564,10 +563,9 @@ uInt8 TIADebug::posP1(int newVal)
 #if 0 // FIXME
   if(newVal > -1)
     myTIA.myPOSP1 = newVal;
-
-  return myTIA.myPOSP1;
 #endif
-return 0;
+
+  return myTIA.myPlayer1.getPosition();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

src/emucore/tia/Player.cxx

@@ -363,6 +363,15 @@ void Player::applyColors()
   myColor = myDebugEnabled ? myDebugColor : myObjectColor;
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+uInt8 Player::getPosition() const
+{
+  const uInt8 shift = myDivider == 1 ? 0 : 1;
+
+  // Mind the sign of renderCounterOffset: it's defined negative above
+  return (316 - myCounter - Count::renderCounterOffset + shift + myPositioningProvider->getPosition()) % 160;
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool Player::save(Serializer& out) const
 {

src/emucore/tia/Player.hxx

@@ -18,8 +18,9 @@
 #ifndef TIA_PLAYER
 #define TIA_PLAYER
 
-#include "Serializable.hxx"
 #include "bspf.hxx"
+#include "Serializable.hxx"
+#include "PositioningProvider.hxx"
 
 class Player : public Serializable
 {
@@ -28,6 +29,10 @@ class Player : public Serializable
 
   public:
 
+    void setPositioningProvider(PositioningProvider* positioningProvider) {
+      myPositioningProvider = positioningProvider;
+    }
+
     void reset();
 
     void grp(uInt8 value);
@@ -68,6 +73,8 @@ class Player : public Serializable
 
     uInt8 getRespClock() const;
 
+    uInt8 getPosition() const;
+
     /**
       Serializable methods (see that class for more information).
     */
@@ -118,6 +125,8 @@ class Player : public Serializable
     bool myIsReflected;
     bool myIsDelaying;
 
+    PositioningProvider *myPositioningProvider;
+
   private:
     Player(const Player&) = delete;
     Player(Player&&) = delete;

src/emucore/tia/PositioningProvider.hxx

@@ -0,0 +1,45 @@
+//============================================================================
+//
+//   SSSS    tt          lll  lll
+//  SS  SS   tt           ll   ll
+//  SS     tttttt  eeee   ll   ll   aaaa
+//   SSSS    tt   ee  ee  ll   ll      aa
+//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
+//  SS  SS   tt   ee      ll   ll  aa  aa
+//   SSSS     ttt  eeeee llll llll  aaaaa
+//
+// Copyright (c) 1995-2017 by Bradford W. Mott, Stephen Anthony
+// and the Stella Team
+//
+// See the file "License.txt" for information on usage and redistribution of
+// this file, and for a DISCLAIMER OF ALL WARRANTIES.
+//============================================================================
+
+#ifndef TIA_POSITIONING_PROVIDER
+#define TIA_POSITIONING_PROVIDER
+
+#include "bspf.hxx"
+
+/**
+  This is an abstract interface class that provides a subset of TIA
+  functionality for sprite positioning while avoiding circular dependencies
+  between TIA and sprites.
+
+  @author  Christian Speckner (DirtyHairy) and Stephen Anthony
+*/
+class PositioningProvider
+{
+  public:
+
+    /**
+      Get the current x value
+    */
+    virtual uInt8 getPosition() = 0;
+
+  protected:
+
+    ~PositioningProvider() = default;
+
+};
+
+#endif // TIA_POSITIONING_PROVIDER

src/emucore/tia/TIA.cxx

@@ -95,6 +95,9 @@ TIA::TIA(Console& console, Sound& sound, Settings& settings)
 
   myTIAPinsDriven = mySettings.getBool("tiadriven");
 
+  myPlayer0.setPositioningProvider(this);
+  myPlayer1.setPositioningProvider(this);
+
   reset();
 }
 

src/emucore/tia/TIA.hxx

@@ -35,6 +35,7 @@
 #include "Ball.hxx"
 #include "LatchedInput.hxx"
 #include "PaddleReader.hxx"
+#include "PositioningProvider.hxx"
 
 /**
   This class is a device that emulates the Television Interface Adaptor
@@ -49,7 +50,7 @@
 
   @author  Christian Speckner (DirtyHairy) and Stephen Anthony
 */
-class TIA : public Device
+class TIA : public Device, public PositioningProvider
 {
   public:
     friend class TIADebug;
@@ -308,9 +309,16 @@ class TIA : public Device
     */
     void updateScanlineByTrace(int target);
 
-    // Retrieve the last value written to a certain register
+    /**
+      Retrieve the last value written to a certain register
+    */
     uInt8 lastValueWrittenToRegister(uInt8 reg) const;
 
+    /**
+      Get the current x value
+    */
+    virtual uInt8 getPosition() {return (myHctr < 68) ? 0 : (myHctr - 68 - myXDelta);}
+
     /**
       Save the current state of this device to the given Serializer.