From 92754ace7a03f9df256415525ab403bc55f03e2e Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 29 Jan 2017 22:16:23 -0500
Subject: [PATCH] Some mild fixes get me up to having a rolling screen of
 vertical lines. Which is what I was hoping for right now!

---
 Machines/Atari2600/Atari2600.cpp              |  4 +-
 Machines/Atari2600/TIA.cpp                    | 43 ++++++++++++++++---
 Machines/Atari2600/TIA.hpp                    |  8 +++-
 .../xcschemes/Clock Signal.xcscheme           |  1 -
 4 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index cd67696a0..7f7f70ea6 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -130,8 +130,8 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
 			} else {
 				const uint16_t decodedAddress = address & 0x3f;
 				switch(decodedAddress) {
-					case 0x00:	update_video(); tia_->set_vsync(!!(*value & 0x02));		break;
-					case 0x01:	update_video();	tia_->set_vblank(!!(*value & 0x02));	break;
+					case 0x00:	update_video(); tia_->set_sync(!!(*value & 0x02));	break;
+					case 0x01:	update_video();	tia_->set_blank(!!(*value & 0x02));	break;
 
 					case 0x02:
 						set_ready_line(true);
diff --git a/Machines/Atari2600/TIA.cpp b/Machines/Atari2600/TIA.cpp
index 0a515bea1..2dbdd4c03 100644
--- a/Machines/Atari2600/TIA.cpp
+++ b/Machines/Atari2600/TIA.cpp
@@ -11,12 +11,17 @@
 using namespace Atari2600;
 namespace {
 	const int cycles_per_line = 228;
+
+	const int sync_flag	= 0x1;
+	const int blank_flag = 0x2;
 }
 
 TIA::TIA() :
 	horizontal_counter_(0),
 	output_cursor_(0),
-	pixel_target_(nullptr)
+	pixel_target_(nullptr),
+	requested_output_mode_(0),
+	output_mode_(0)
 {
 	crt_.reset(new Outputs::CRT::CRT(cycles_per_line * 2 + 1, 1, Outputs::CRT::DisplayType::NTSC60, 1));
 	crt_->set_output_device(Outputs::CRT::Television);
@@ -95,12 +100,14 @@ void TIA::run_for_cycles(int number_of_cycles)
 	}
 }
 
-void TIA::set_vsync(bool vsync)
+void TIA::set_sync(bool sync)
 {
+	requested_output_mode_ = (requested_output_mode_ & ~sync_flag) | (sync ? sync_flag : 0);
 }
 
-void TIA::set_vblank(bool vblank)
+void TIA::set_blank(bool blank)
 {
+	requested_output_mode_ = (requested_output_mode_ & ~blank_flag) | (blank ? blank_flag : 0);
 }
 
 void TIA::reset_horizontal_counter()
@@ -230,7 +237,12 @@ void TIA::output_for_cycles(int number_of_cycles)
 			8 cycles:	blank or pixels, depending on whether the blank extend bit is set
 			152 cycles:	pixels
 	*/
+//	if(output_mode_ != requested_output_mode_)
+//	{
+//		// flush the old output
+//	}
 	horizontal_counter_ += number_of_cycles;
+
 	if(!output_cursor_ && horizontal_counter_ >= 16)
 	{
 		crt_->output_blank(32);
@@ -248,7 +260,7 @@ void TIA::output_for_cycles(int number_of_cycles)
 	}
 	if(output_cursor_ == 48 && horizontal_counter_ >= 68)
 	{
-		crt_->output_default_colour_burst(40);
+		crt_->output_blank(40);
 		output_cursor_ = 68;
 	}
 	if(horizontal_counter_ > 68)
@@ -272,10 +284,29 @@ void TIA::output_for_cycles(int number_of_cycles)
 		}
 	}
 	horizontal_counter_ %= cycles_per_line;
+	output_cursor_ %= cycles_per_line;
 }
 
 void TIA::output_line()
 {
-	// TODO: optimise special case
-	output_for_cycles(cycles_per_line);
+	output_mode_ = requested_output_mode_;
+	switch(output_mode_)
+	{
+		default:
+			// TODO: optimise special case
+			output_for_cycles(cycles_per_line);
+		break;
+		case sync_flag:
+		case sync_flag | blank_flag:
+			crt_->output_sync(32);
+			crt_->output_blank(32);
+			crt_->output_sync(392);
+		break;
+		case blank_flag:
+			crt_->output_blank(32);
+			crt_->output_sync(32);
+			crt_->output_default_colour_burst(32);
+			crt_->output_blank(360);
+		break;
+	}
 }
diff --git a/Machines/Atari2600/TIA.hpp b/Machines/Atari2600/TIA.hpp
index b79fb3274..e5ec60a17 100644
--- a/Machines/Atari2600/TIA.hpp
+++ b/Machines/Atari2600/TIA.hpp
@@ -26,8 +26,8 @@ class TIA {
 		void run_for_cycles(int number_of_cycles);
 		void set_output_mode(OutputMode output_mode);
 
-		void set_vsync(bool vsync);
-		void set_vblank(bool vblank);
+		void set_sync(bool sync);
+		void set_blank(bool blank);
 		void reset_horizontal_counter(); 						// Reset is delayed by four cycles.
 
 		int get_cycles_until_horizontal_blank(unsigned int from_offset);
@@ -68,7 +68,11 @@ class TIA {
 		std::shared_ptr<Outputs::CRT::CRT> crt_;
 
 		int horizontal_counter_;
+
 		int output_cursor_;
+		int output_mode_;
+		int requested_output_mode_;
+
 		uint8_t *pixel_target_;
 
 		void output_for_cycles(int number_of_cycles);
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme
index 08fb44b13..6cceb313b 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme	
@@ -69,7 +69,6 @@
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"
-      enableAddressSanitizer = "YES"
       debugServiceExtension = "internal"
       allowLocationSimulation = "NO">
       <BuildableProductRunnable