Added debugger pseudo-registers to detect timer access on wraparound (fixes #606).

Changes.txt

@@ -53,6 +53,10 @@
 
   * Added option to disable aspect correct scaling.
 
+  * Added debugger pseudo-registers '_timwrapread' and '_timwrapwrite',
+    which are set when the RIOT timer is read/written on timer wraparound,
+    respectively.
+
   * Bankswitching schemes BUS, DPC+ and CDFx now work when startup bank
     randomization is enabled (these schemes now ignore that setting).
 

src/debugger/Debugger.cxx

@@ -877,23 +877,26 @@ std::array<Debugger::BuiltinFunction, 18> Debugger::ourBuiltinFunctions = { {
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 // Names are defined here, but processed in YaccParser
-std::array<Debugger::PseudoRegister, 12> Debugger::ourPseudoRegisters = { {
+std::array<Debugger::PseudoRegister, 14> Debugger::ourPseudoRegisters = { {
 // Debugger::PseudoRegister Debugger::ourPseudoRegisters[NUM_PSEUDO_REGS] = {
-  { "_bank",      "Currently selected bank" },
+  { "_bank",          "Currently selected bank" },
-  { "_cclocks",   "Color clocks on current scanline" },
+  { "_cclocks",       "Color clocks on current scanline" },
-  { "_cycleshi",  "Higher 32 bits of number of cycles since emulation started" },
+  { "_cycleshi",      "Higher 32 bits of number of cycles since emulation started" },
-  { "_cycleslo",  "Lower 32 bits of number of cycles since emulation started" },
+  { "_cycleslo",      "Lower 32 bits of number of cycles since emulation started" },
-  { "_fcount",    "Number of frames since emulation started" },
+  { "_fcount",        "Number of frames since emulation started" },
-  { "_fcycles",   "Number of cycles since frame started" },
+  { "_fcycles",       "Number of cycles since frame started" },
-  { "_icycles",   "Number of cycles of last instruction" },
+  { "_icycles",       "Number of cycles of last instruction" },
-  { "_scan",      "Current scanline count" },
+  { "_scan",          "Current scanline count" },
-  { "_scanend",   "Scanline count at end of last frame" },
+  { "_scanend",       "Scanline count at end of last frame" },
-  { "_scycles",   "Number of cycles in current scanline" },
+  { "_scycles",       "Number of cycles in current scanline" },
-  { "_vblank",    "Whether vertical blank is enabled (1 or 0)" },
+  { "_timwrapread",   "Timer read wrapped on this cycle" },
-  { "_vsync",     "Whether vertical sync is enabled (1 or 0)" }
+  { "_timwrapwrite",  "Timer write wrapped on this cycle" },
+  { "_vblank",        "Whether vertical blank is enabled (1 or 0)" },
+  { "_vsync",         "Whether vertical sync is enabled (1 or 0)" }
   // CPU address access functions:
   /*{ "_lastread", "last CPU read address" },
   { "_lastwrite", "last CPU write address" },
   { "__lastbaseread", "last CPU read base address" },
   { "__lastbasewrite", "last CPU write base address" }*/
 } };
+//

src/debugger/Debugger.hxx

@@ -363,7 +363,7 @@ class Debugger : public DialogContainer
       string name, help;
     };
     static std::array<BuiltinFunction, 18> ourBuiltinFunctions;
-    static std::array<PseudoRegister, 12> ourPseudoRegisters;
+    static std::array<PseudoRegister, 14> ourPseudoRegisters;
 
   private:
     // rewind/unwind n states

src/debugger/DebuggerExpressions.hxx

@@ -23,6 +23,7 @@
 #include "bspf.hxx"
 #include "CartDebug.hxx"
 #include "CpuDebug.hxx"
+#include "RiotDebug.hxx"
 #include "TIADebug.hxx"
 #include "Debugger.hxx"
 #include "Expression.hxx"
@@ -310,6 +311,18 @@ class ShiftRightExpression : public Expression
       { return myLHS->evaluate() >> myRHS->evaluate(); }
 };
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+class RiotMethodExpression : public Expression
+{
+  public:
+    RiotMethodExpression(RiotMethod method) : Expression(), myMethod(std::mem_fn(method)) { }
+    Int32 evaluate() const override
+      { return myMethod(Debugger::debugger().riotDebug()); }
+
+  private:
+    std::function<int(const RiotDebug&)> myMethod;
+};
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 class TiaMethodExpression : public Expression
 {

src/debugger/RiotDebug.cxx

@@ -235,6 +235,18 @@ Int32 RiotDebug::timDivider() const
   return mySystem.m6532().myDivider;
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+int RiotDebug::timWrappedOnRead() const
+{
+  return mySystem.m6532().myTimWrappedOnRead;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+int RiotDebug::timWrappedOnWrite() const
+{
+  return mySystem.m6532().myTimWrappedOnWrite;
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool RiotDebug::diffP0(int newVal)
 {

src/debugger/RiotDebug.hxx

@@ -22,6 +22,10 @@ class M6532;
 class Debugger;
 class RiotDebug;
 
+// Function type for RiotDebug instance methods
+class RiotDebug;
+using RiotMethod = int (RiotDebug::*)() const;
+
 #include "DebuggerSystem.hxx"
 
 class RiotState : public DebuggerState
@@ -75,6 +79,9 @@ class RiotDebug : public DebuggerSystem
     Int32 timClocks() const;
     Int32 intimClocks() const;
     Int32 timDivider() const;
+    /* Debugger pseudo-registers for timer accesses */
+    int timWrappedOnRead() const;
+    int timWrappedOnWrite() const;
 
     /* Console switches */
     bool diffP0(int newVal = -1);

src/emucore/M6532.cxx

@@ -145,6 +145,10 @@ void M6532::updateEmulation()
   }
 
   myLastCycle = mySystem->cycles();
+
+#ifdef DEBUGGER_SUPPORT
+  myTimWrappedOnRead = myTimWrappedOnWrite = false;
+#endif
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -220,7 +224,9 @@ uInt8 M6532::peek(uInt16 addr)
     {
       // Timer Flag is always cleared when accessing INTIM
       if (!myWrappedThisCycle) myInterruptFlag &= ~TimerBit;
-
+  #ifdef DEBUGGER_SUPPORT
+      myTimWrappedOnRead = myWrappedThisCycle;
+  #endif
       return myTimer;
     }
 
@@ -316,6 +322,9 @@ void M6532::setTimerRegister(uInt8 value, uInt8 interval)
 
   // Interrupt timer flag is cleared (and invalid) when writing to the timer
   if (!myWrappedThisCycle) myInterruptFlag &= ~TimerBit;
+#ifdef DEBUGGER_SUPPORT
+  myTimWrappedOnWrite = myWrappedThisCycle;
+#endif
 
   mySetTimerCycle = mySystem->cycles();
 }

src/emucore/M6532.hxx

@@ -250,6 +250,10 @@ class M6532 : public Device
     std::array<Device::AccessCounter, IO_SIZE * 2>    myIOAccessCounter;
     // The array used to skip the first ZP access tracking
     std::array<uInt8, RAM_SIZE>   myZPAccessDelay;
+
+    // Detect timer being accessed on wraparound
+    bool myTimWrappedOnRead{false};
+    bool myTimWrappedOnWrite{false};
 #endif // DEBUGGER_SUPPORT
 
   private:

src/yacc/YaccParser.cxx

@@ -228,6 +228,18 @@ CpuMethod getCpuSpecial(char* ch)
     return nullptr;
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+// special methods that get RIOT internal state
+RiotMethod getRiotSpecial(char* ch)
+{
+  if(BSPF::equalsIgnoreCase(ch, "_timwrapread"))
+    return &RiotDebug::timWrappedOnRead;
+  else if(BSPF::equalsIgnoreCase(ch, "_timwrapwrite"))
+    return &RiotDebug::timWrappedOnWrite;
+  else
+    return nullptr;
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 // special methods that get TIA internal state
 TiaMethod getTiaSpecial(char* ch)
@@ -281,6 +293,7 @@ int yylex() {
         {
           CartMethod cartMeth;
           CpuMethod  cpuMeth;
+          RiotMethod riotMeth;
           TiaMethod  tiaMeth;
 
           char *bufp = idbuf;
@@ -309,6 +322,9 @@ int yylex() {
           } else if( (cartMeth = getCartSpecial(idbuf)) ) {
             yylval.cartMethod = cartMeth;
             return CART_METHOD;
+          } else if( (riotMeth = getRiotSpecial(idbuf)) ) {
+            yylval.riotMethod = riotMeth;
+            return RIOT_METHOD;
           } else if( (tiaMeth = getTiaSpecial(idbuf)) ) {
             yylval.tiaMethod = tiaMeth;
             return TIA_METHOD;

src/yacc/YaccParser.hxx

@@ -21,6 +21,7 @@
 #include "Expression.hxx"
 #include "CartDebug.hxx"
 #include "CpuDebug.hxx"
+#include "RiotDebug.hxx"
 #include "TIADebug.hxx"
 
 #include "bspf.hxx"
@@ -37,6 +38,7 @@ namespace YaccParser
 
   CartMethod getCartSpecial(char* ch);
   CpuMethod getCpuSpecial(char* ch);
+  RiotMethod getRiotSpecial(char* ch);
   TiaMethod getTiaSpecial(char* ch);
 }
 

src/yacc/stella.y

@@ -30,6 +30,7 @@ void yyerror(const char *e) {
 	char* Equate;
 	CartMethod cartMethod;
 	CpuMethod cpuMethod;
+	RiotMethod riotMethod;
 	TiaMethod tiaMethod;
 	Expression* exp;
 	char* DefinedFunction;
@@ -41,6 +42,7 @@ void yyerror(const char *e) {
 %token <Equate> EQUATE
 %token <cartMethod> CART_METHOD
 %token <cpuMethod>  CPU_METHOD
+%token <riotMethod> RIOT_METHOD
 %token <tiaMethod>  TIA_METHOD
 %token <DefinedFunction> FUNCTION
 
@@ -97,6 +99,7 @@ expression:	expression '+' expression { if(DEBUG_EXP) fprintf(stderr, " +"); $$
 	|	EQUATE { if(DEBUG_EXP) fprintf(stderr, "equate %s", $1); $$ = new EquateExpression($1); lastExp = $$; }
 	|	CPU_METHOD { if(DEBUG_EXP) fprintf(stderr, " (CpuMethod)"); $$ = new CpuMethodExpression($1); lastExp = $$; }
 	|	CART_METHOD { if(DEBUG_EXP) fprintf(stderr, " (CartMethod)"); $$ = new CartMethodExpression($1); lastExp = $$; }
+	|	RIOT_METHOD { if(DEBUG_EXP) fprintf(stderr, " (RiotMethod)"); $$ = new RiotMethodExpression($1); lastExp = $$; }
 	|	TIA_METHOD { if(DEBUG_EXP) fprintf(stderr, " (TiaMethod)"); $$ = new TiaMethodExpression($1); lastExp = $$; }
 	|	FUNCTION { if(DEBUG_EXP) fprintf(stderr, " (DefinedFunction)"); $$ = new FunctionExpression($1); lastExp = $$; }
 	|  ERR { if(DEBUG_EXP) fprintf(stderr, " ERR: "); yyerror((const char*)"Invalid label or constant"); return 1; }

src/yacc/y.tab.h

@@ -1,8 +1,9 @@
-/* A Bison parser, made by GNU Bison 3.0.4.  */
+/* A Bison parser, made by GNU Bison 3.5.1.  */
 
 /* Bison interface for Yacc-like parsers in C
 
-   Copyright (C) 1984, 1989-1990, 2000-2015 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2020 Free Software Foundation,
+   Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -30,6 +31,9 @@
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
+/* Undocumented macros, especially those whose name start with YY_,
+   are private implementation details.  Do not rely on them.  */
+
 #ifndef YY_YY_Y_TAB_H_INCLUDED
 # define YY_YY_Y_TAB_H_INCLUDED
 /* Debug traces.  */
@@ -50,19 +54,20 @@ extern int yydebug;
     EQUATE = 260,
     CART_METHOD = 261,
     CPU_METHOD = 262,
-    TIA_METHOD = 263,
+    RIOT_METHOD = 263,
-    FUNCTION = 264,
+    TIA_METHOD = 264,
-    LOG_OR = 265,
+    FUNCTION = 265,
-    LOG_AND = 266,
+    LOG_OR = 266,
-    LOG_NOT = 267,
+    LOG_AND = 267,
-    SHR = 268,
+    LOG_NOT = 268,
-    SHL = 269,
+    SHR = 269,
-    GTE = 270,
+    SHL = 270,
-    LTE = 271,
+    GTE = 271,
-    NE = 272,
+    LTE = 272,
-    EQ = 273,
+    NE = 273,
-    DEREF = 274,
+    EQ = 274,
-    UMINUS = 275
+    DEREF = 275,
+    UMINUS = 276
   };
 #endif
 /* Tokens.  */
@@ -71,38 +76,39 @@ extern int yydebug;
 #define EQUATE 260
 #define CART_METHOD 261
 #define CPU_METHOD 262
-#define TIA_METHOD 263
+#define RIOT_METHOD 263
-#define FUNCTION 264
+#define TIA_METHOD 264
-#define LOG_OR 265
+#define FUNCTION 265
-#define LOG_AND 266
+#define LOG_OR 266
-#define LOG_NOT 267
+#define LOG_AND 267
-#define SHR 268
+#define LOG_NOT 268
-#define SHL 269
+#define SHR 269
-#define GTE 270
+#define SHL 270
-#define LTE 271
+#define GTE 271
-#define NE 272
+#define LTE 272
-#define EQ 273
+#define NE 273
-#define DEREF 274
+#define EQ 274
-#define UMINUS 275
+#define DEREF 275
+#define UMINUS 276
 
 /* Value type.  */
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
-
 union YYSTYPE
 {
-#line 28 "stella.y" /* yacc.c:1909  */
+#line 28 "stella.y"
 
 	int val;
 	char* Equate;
 	CartMethod cartMethod;
 	CpuMethod cpuMethod;
+	RiotMethod riotMethod;
 	TiaMethod tiaMethod;
 	Expression* exp;
 	char* DefinedFunction;
 
-#line 104 "y.tab.h" /* yacc.c:1909  */
+#line 110 "y.tab.h"
-};
 
+};
 typedef union YYSTYPE YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1
 # define YYSTYPE_IS_DECLARED 1