From eff25e007eb88a4cd9c9737f2359c9530d34d816 Mon Sep 17 00:00:00 2001
From: Thomas Jentzsch <tjentzsch@yahoo.de>
Date: Sun, 27 Jun 2021 13:04:35 +0200
Subject: [PATCH] fixed a bug in branch cycle counting (now the test value is
 less than 0.1% off)

---
 src/debugger/gui/CartARMWidget.cxx | 2 +-
 src/emucore/Settings.cxx           | 2 +-
 src/emucore/Thumbulator.cxx        | 9 +++++----
 src/emucore/Thumbulator.hxx        | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/debugger/gui/CartARMWidget.cxx b/src/debugger/gui/CartARMWidget.cxx
index ab6cb38e4..aca0f7b9b 100644
--- a/src/debugger/gui/CartARMWidget.cxx
+++ b/src/debugger/gui/CartARMWidget.cxx
@@ -49,7 +49,7 @@ void CartridgeARMWidget::addCycleWidgets(int xpos, int ypos)
   myCycleFactor = new SliderWidget(_boss, _font, myIncCycles->getRight() + _fontWidth * 2, ypos - 1,
                                    _fontWidth * 10, _lineHeight, "Cycle factor", _fontWidth * 14,
                                    kFactorChanged, _fontWidth * 4, "%");
-  myCycleFactor->setMinValue(80); myCycleFactor->setMaxValue(100);
+  myCycleFactor->setMinValue(90); myCycleFactor->setMaxValue(110);
   myCycleFactor->setTickmarkIntervals(4);
   myCycleFactor->setToolTip("Correct approximated ARM cycles by factor.");
   myCycleFactor->setTarget(this);
diff --git a/src/emucore/Settings.cxx b/src/emucore/Settings.cxx
index 6c731e420..4a74dfc1e 100644
--- a/src/emucore/Settings.cxx
+++ b/src/emucore/Settings.cxx
@@ -248,7 +248,7 @@ Settings::Settings()
   setPermanent("dev.thumb.trapfatal", "true");
 #ifdef DEBUGGER_SUPPORT
   setPermanent("dev.thumb.inccycles", "true");
-  setPermanent("dev.thumb.cyclefactor", "0.95");
+  setPermanent("dev.thumb.cyclefactor", "1.05");
   setPermanent("dev.thumb.chiptype", "0"); // = LPC2103
   setPermanent("dev.thumb.mammode", "2");
 #endif
diff --git a/src/emucore/Thumbulator.cxx b/src/emucore/Thumbulator.cxx
index 6a6042e30..8a79b49c7 100644
--- a/src/emucore/Thumbulator.cxx
+++ b/src/emucore/Thumbulator.cxx
@@ -629,8 +629,8 @@ void Thumbulator::write_register(uInt32 reg, uInt32 data, bool isFlowBreak)
     if(isFlowBreak)
     {
       // dummy fetch + fill the pipeline
-      INC_N_CYCLES(reg_norm[15] + 4, AccessType::data);
-      INC_S_CYCLES(data, AccessType::branch);
+      INC_N_CYCLES(reg_norm[15] - 2, AccessType::prefetch);
+      INC_S_CYCLES(data - 2, AccessType::branch);
     }
   }
 //#endif
@@ -1176,13 +1176,14 @@ int Thumbulator::execute()
 
     //B(1) conditional branch
     case Op::b1: {
-      rb = (inst >> 0) & 0xFF;
+      rb = inst & 0xFF;
       if(rb & 0x80)
         rb |= (~0U) << 8;
-      op=(inst >> 8) & 0xF;
       rb <<= 1;
       rb += pc;
       rb += 2;
+
+      op = (inst >> 8) & 0xF;
       switch(op)
       {
         case 0x0: //b eq  z set
diff --git a/src/emucore/Thumbulator.hxx b/src/emucore/Thumbulator.hxx
index 3d5707a9d..c63cc9fef 100644
--- a/src/emucore/Thumbulator.hxx
+++ b/src/emucore/Thumbulator.hxx
@@ -300,7 +300,7 @@ class Thumbulator
     bool _lockMamcr{false};
 
   #ifdef THUMB_CYCLE_COUNT
-    double _armCyclesFactor{0.90};
+    double _armCyclesFactor{1.05};
     CycleType _fetchCycleType{CycleType::S};
    #ifdef EMULATE_PIPELINE
     uInt32 _fetchPipeline{0}; // reserve fetch cycles resulting from pipelining (execution stage)