From c6a5b96796433358a32dbb175851026d58ffbf5d Mon Sep 17 00:00:00 2001
From: thrust26 <tjentzsch@yahoo.de>
Date: Fri, 13 Oct 2017 11:17:53 +0200
Subject: [PATCH] fixes #244 (wrong source address display for cleared peeks)

---
 src/debugger/DiStella.cxx |  7 +++++++
 src/emucore/M6502.ins     | 20 ++++++++++----------
 src/emucore/M6502.m4      |  4 ++--
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/src/debugger/DiStella.cxx b/src/debugger/DiStella.cxx
index a0705c6e9..c9c470185 100644
--- a/src/debugger/DiStella.cxx
+++ b/src/debugger/DiStella.cxx
@@ -120,6 +120,12 @@ void DiStella::disasm(uInt32 distart, int pass)
   myPC = distart - myOffset;
   while (myPC <= myAppData.end) {
 
+    // since -1 is used in m6502.m4 for clearing the last peek
+    // and this results into an access at e.g. 0xffff,
+    // we have to fix the consequences here (ugly!).
+    if(myPC == myAppData.end)
+      goto FIX_LAST;
+
     if (checkBits(myPC, CartDebug::GFX | CartDebug::PGFX,
         CartDebug::CODE)) {
       if (pass == 2)
@@ -137,6 +143,7 @@ void DiStella::disasm(uInt32 distart, int pass)
         myPC++;
     } else if (checkBits(myPC, CartDebug::ROW,
                CartDebug::CODE | CartDebug::DATA | CartDebug::GFX | CartDebug::PGFX)) {
+FIX_LAST:
       if (pass == 2)
         mark(myPC + myOffset, CartDebug::VALID_ENTRY);
 
diff --git a/src/emucore/M6502.ins b/src/emucore/M6502.ins
index 0ea0115b5..53256c733 100644
--- a/src/emucore/M6502.ins
+++ b/src/emucore/M6502.ins
@@ -38,7 +38,7 @@
 
 #ifndef CLEAR_LAST_PEEK
   #ifdef DEBUGGER_SUPPORT
-    #define CLEAR_LAST_PEEK(_addr) _addr = 0;
+    #define CLEAR_LAST_PEEK(_addr) _addr = -1;
   #else
     #define CLEAR_LAST_PEEK(_addr)
   #endif
@@ -428,7 +428,7 @@ case 0x7d:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -700,7 +700,7 @@ case 0x3d:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -1232,7 +1232,7 @@ case 0xdd:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -1700,7 +1700,7 @@ case 0x5d:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -2416,7 +2416,7 @@ case 0xbd:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -2646,7 +2646,7 @@ case 0xbc:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -2853,7 +2853,7 @@ case 0xfc:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -2930,7 +2930,7 @@ case 0x1d:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
@@ -3976,7 +3976,7 @@ case 0xfd:
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);
diff --git a/src/emucore/M6502.m4 b/src/emucore/M6502.m4
index 78171780c..85776530e 100644
--- a/src/emucore/M6502.m4
+++ b/src/emucore/M6502.m4
@@ -38,7 +38,7 @@
 
 #ifndef CLEAR_LAST_PEEK
   #ifdef DEBUGGER_SUPPORT
-    #define CLEAR_LAST_PEEK(_addr) _addr = 0;
+    #define CLEAR_LAST_PEEK(_addr) _addr = -1;
   #else
     #define CLEAR_LAST_PEEK(_addr)
   #endif
@@ -88,7 +88,7 @@ define(M6502_ABSOLUTEX_READ, `{
     operand = peek(intermediateAddress, DISASM_NONE);
     intermediateAddress = (high | low) + X;
     operand = peek(intermediateAddress, DISASM_DATA);
-  } 
+  }
   else
   {
     operand = peek(intermediateAddress, DISASM_DATA);