Fixed INTIM/TIMINT multiple reads in the debugger, which changed the

state of the registers and messed up further emulation.


git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@2614 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba

Changes.txt

@@ -53,6 +53,10 @@
   * Fixed regression in RIOT INTIM reads; at least one known ROM
     (Mr. Roboto Berzerk hack) wasn't working properly.
 
+  * Fixed bug in the debugger with RIOT INTIM/TIMINT display; reads
+    were being done multiple times, changing the state of the
+    registers and resulting in incorrect emulation.
+
   * Added support for different directories for saving/loading PNG
     files.  These are set with the 'snapsavedir' and 'snaploaddir'
     commandline arguments (which replace the old 'snapdir'), and are

src/debugger/RiotDebug.cxx

@@ -20,7 +20,6 @@
 #include <sstream>
 
 #include "System.hxx"
-#include "M6532.hxx"
 #include "TIA.hxx"
 #include "Debugger.hxx"
 #include "Switches.hxx"
@@ -129,7 +128,7 @@ uInt8 RiotDebug::swacnt(int newVal)
   if(newVal > -1)
     mySystem.poke(0x281, newVal);
 
-  return mySystem.peek(0x281);
+  return mySystem.m6532().myDDRA;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -138,7 +137,7 @@ uInt8 RiotDebug::swbcnt(int newVal)
   if(newVal > -1)
     mySystem.poke(0x283, newVal);
 
-  return mySystem.peek(0x283);
+  return mySystem.m6532().myDDRB;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -196,24 +195,6 @@ uInt8 RiotDebug::tim1024T(int newVal)
   return mySystem.m6532().myOutTimer[3];
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-uInt8 RiotDebug::intim()
-{
-  return mySystem.peek(0x284);
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-uInt8 RiotDebug::timint()
-{
-  return mySystem.peek(0x285);
-}
-
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-Int32 RiotDebug::timClocks()
-{
-  return mySystem.m6532().timerClocks();
-}
-
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Controller& RiotDebug::controller(Controller::Jack jack) const
 {

src/debugger/RiotDebug.hxx

@@ -24,6 +24,7 @@ class Debugger;
 class RiotDebug;
 
 #include "Array.hxx"
+#include "M6532.hxx"
 #include "DebuggerSystem.hxx"
 
 class RiotState : public DebuggerState
@@ -71,9 +72,9 @@ class RiotDebug : public DebuggerSystem
     uInt8 tim8T(int newVal = -1);
     uInt8 tim64T(int newVal = -1);
     uInt8 tim1024T(int newVal = -1);
-    uInt8 intim();
-    uInt8 timint();
-    Int32 timClocks();
+    uInt8 intim() const     { return mySystem.m6532().intim();       }
+    uInt8 timint() const    { return mySystem.m6532().timint();      }
+    Int32 timClocks() const { return mySystem.m6532().timerClocks(); }
 
     /* Controller ports */
     Controller& controller(Controller::Jack jack) const;

src/emucore/M6532.cxx

@@ -401,6 +401,34 @@ bool M6532::load(Serializer& in)
   return true;
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+uInt8 M6532::intim() const
+{
+  // This method is documented in ::peek(0x284), and exists so that the
+  // debugger can read INTIM without changing the state of the system
+
+  // Get number of clocks since timer was set
+  Int32 timer = timerClocks();  
+  if(!(timer & 0x40000))
+    return (timer >> myIntervalShift) & 0xff;
+  else
+    return timer & 0xff;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+uInt8 M6532::timint() const
+{
+  // This method is documented in ::peek(0x285), and exists so that the
+  // debugger can read TIMINT without changing the state of the system
+
+  // Update timer flag if it is invalid and timer has expired
+  uInt8 interrupt = myInterruptFlag;
+  if(timerClocks() < 0)
+    interrupt |= TimerBit;
+
+  return interrupt;
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 M6532::M6532(const M6532& c)
   : myConsole(c.myConsole),

src/emucore/M6532.hxx

@@ -140,12 +140,18 @@ class M6532 : public Device
     bool poke(uInt16 address, uInt8 value);
 
   private:
-    Int32 timerClocks()
+    Int32 timerClocks() const
       { return myTimer - (mySystem->cycles() - myCyclesWhenTimerSet); }
 
     void setTimerRegister(uInt8 data, uInt8 interval);
     void setPinState(bool shcha);
 
+    // The following are used by the debugger to read INTIM/TIMINT
+    // We need separate methods to do this, so the state of the system
+    // isn't changed
+    uInt8 intim() const;
+    uInt8 timint() const;
+
   private:
     // Accessible bits in the interrupt flag register
     // All other bits are always zeroed