From a379ad4c1aed147a3dd33e2fc8c613dda8695aca Mon Sep 17 00:00:00 2001
From: Stephen Anthony <sa666666@gmail.com>
Date: Mon, 4 May 2020 14:19:02 -0230
Subject: [PATCH] Added '_scanend' pseudo-register to track scanlines at end of
 last frame.  Fixes #624.

---
 Changes.txt               | 3 +++
 docs/debugger.html        | 1 +
 src/debugger/Debugger.cxx | 5 +++--
 src/debugger/Debugger.hxx | 2 +-
 src/yacc/YaccParser.cxx   | 4 +++-
 5 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/Changes.txt b/Changes.txt
index 2fe5ad2b5..2fb02da2b 100644
--- a/Changes.txt
+++ b/Changes.txt
@@ -40,6 +40,9 @@
 
   * Removed unused CV+ and DASH bank switching types.
 
+  * Added debugger pseudo-register '_scanend', which gives the number of
+    scanlines at the end of the last frame.
+
 -Have fun!
 
 
diff --git a/docs/debugger.html b/docs/debugger.html
index 4f0c1cf6f..91e71bd47 100644
--- a/docs/debugger.html
+++ b/docs/debugger.html
@@ -755,6 +755,7 @@ that holds 'number of scanlines' on an actual console).</p>
 <tr><td> _fcycles</td><td> Number of cycles since frame started</td></tr>
 <tr><td> _icycles</td><td> Number of cycles of last instruction</td></tr>
 <tr><td> _scan</td><td> Current scanline count</td></tr>
+<tr><td> _scanend</td><td> Scanline count at end of last frame</td></tr>
 <tr><td> _scycles</td><td> Number of cycles in current scanline</td></tr>
 <tr><td> _vblank</td><td> Whether vertical blank is enabled (1 or 0)</td></tr>
 <tr><td> _vsync</td><td> Whether vertical sync is enabled (1 or 0)</td></tr>
diff --git a/src/debugger/Debugger.cxx b/src/debugger/Debugger.cxx
index 6f5078228..b46570a6a 100644
--- a/src/debugger/Debugger.cxx
+++ b/src/debugger/Debugger.cxx
@@ -875,7 +875,7 @@ std::array<Debugger::BuiltinFunction, 18> Debugger::ourBuiltinFunctions = { {
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 // Names are defined here, but processed in YaccParser
-std::array<Debugger::PseudoRegister, 11> Debugger::ourPseudoRegisters = { {
+std::array<Debugger::PseudoRegister, 12> Debugger::ourPseudoRegisters = { {
 // Debugger::PseudoRegister Debugger::ourPseudoRegisters[NUM_PSEUDO_REGS] = {
   { "_bank",      "Currently selected bank" },
   { "_cclocks",   "Color clocks on current scanline" },
@@ -883,8 +883,9 @@ std::array<Debugger::PseudoRegister, 11> Debugger::ourPseudoRegisters = { {
   { "_cycleslo",  "Lower 32 bits of number of cycles since emulation started" },
   { "_fcount",    "Number of frames since emulation 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" },
+  { "_scanend",   "Scanline count at end of last frame" },
   { "_scycles",   "Number of cycles in current scanline" },
   { "_vblank",    "Whether vertical blank is enabled (1 or 0)" },
   { "_vsync",     "Whether vertical sync is enabled (1 or 0)" }
diff --git a/src/debugger/Debugger.hxx b/src/debugger/Debugger.hxx
index 2b0ce6c1c..d063f2e90 100644
--- a/src/debugger/Debugger.hxx
+++ b/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, 11> ourPseudoRegisters;
+    static std::array<PseudoRegister, 12> ourPseudoRegisters;
 
   private:
     // rewind/unwind n states
diff --git a/src/yacc/YaccParser.cxx b/src/yacc/YaccParser.cxx
index 82163c433..8bc728ca0 100644
--- a/src/yacc/YaccParser.cxx
+++ b/src/yacc/YaccParser.cxx
@@ -234,7 +234,9 @@ TiaMethod getTiaSpecial(char* ch)
 {
   if(BSPF::equalsIgnoreCase(ch, "_scan"))
     return &TIADebug::scanlines;
-  if(BSPF::equalsIgnoreCase(ch, "_scycles"))
+  else if(BSPF::equalsIgnoreCase(ch, "_scanend"))
+    return &TIADebug::scanlinesLastFrame;
+  else if(BSPF::equalsIgnoreCase(ch, "_scycles"))
     return &TIADebug::cyclesThisLine;
   else if(BSPF::equalsIgnoreCase(ch, "_fcount"))
     return &TIADebug::frameCount;