From 38325741dedc6148c6aa331065cb599ea804e3fd Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 10 Dec 2024 21:28:46 -0500
Subject: [PATCH] Forward address information to a video stub.

---
 Machines/Commodore/Plus4/Plus4.cpp            | 14 +++-
 Machines/Commodore/Plus4/Video.hpp            | 81 +++++++++++++++++++
 .../Clock Signal.xcodeproj/project.pbxproj    |  2 +
 3 files changed, 95 insertions(+), 2 deletions(-)
 create mode 100644 Machines/Commodore/Plus4/Video.hpp

diff --git a/Machines/Commodore/Plus4/Plus4.cpp b/Machines/Commodore/Plus4/Plus4.cpp
index 77aa25ef7..e638a3806 100644
--- a/Machines/Commodore/Plus4/Plus4.cpp
+++ b/Machines/Commodore/Plus4/Plus4.cpp
@@ -8,10 +8,10 @@
 
 #include "Plus4.hpp"
 
+#include "Video.hpp"
+
 #include "../../MachineTypes.hpp"
-
 #include "../../../Processors/6502/6502.hpp"
-
 #include "../../../Analyser/Static/Commodore/Target.hpp"
 
 using namespace Commodore::Plus4;
@@ -207,6 +207,15 @@ public:
 					case 0xff04:	timers_.write<4>(*value);	break;
 					case 0xff05:	timers_.write<5>(*value);	break;
 
+					case 0xff06:	video_.write<0xff06>(*value);	break;
+					case 0xff07:	video_.write<0xff07>(*value);	break;
+					case 0xff0c:	video_.write<0xff0c>(*value);	break;
+					case 0xff0d:	video_.write<0xff0d>(*value);	break;
+					case 0xff12:	video_.write<0xff12>(*value);	break;
+					case 0xff14:	video_.write<0xff14>(*value);	break;
+					case 0xff1a:	video_.write<0xff1a>(*value);	break;
+					case 0xff1b:	video_.write<0xff1b>(*value);	break;
+
 					default:
 						printf("TODO: TED write at %04x\n", address);
 				}
@@ -241,6 +250,7 @@ private:
 
 	Cycles timers_subcycles_;
 	Timers timers_;
+	Video video_;
 };
 
 }
diff --git a/Machines/Commodore/Plus4/Video.hpp b/Machines/Commodore/Plus4/Video.hpp
new file mode 100644
index 000000000..86b9f1f6f
--- /dev/null
+++ b/Machines/Commodore/Plus4/Video.hpp
@@ -0,0 +1,81 @@
+//
+//  Video.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/12/2024.
+//  Copyright © 2024 Thomas Harte. All rights reserved.
+//
+
+#pragma once
+
+namespace Commodore::Plus4 {
+
+struct Video {
+public:
+	template <uint16_t address>
+	void write(const uint8_t value) {
+		const auto load_high10 = [&](uint16_t &target) {
+			target = uint16_t(
+				(target & 0x00ff) | ((value & 0x3) << 8)
+			);
+		};
+		const auto load_low8 = [&](uint16_t &target) {
+			target = uint16_t(
+				(target & 0xff00) | value
+			);
+		};
+
+
+		switch(address) {
+			case 0xff06:
+				extended_colour_mode_ = value & 0x40;
+				bitmap_mode_ = value & 0x20;
+				display_enable_ = value & 0x10;
+				rows_25_ = value & 8;
+				y_scroll_ = value & 7;
+			break;
+
+			case 0xff07:
+				characters_256_ = value & 0x80;
+				is_ntsc_ = value & 0x40;
+				ted_off_ = value & 0x20;
+				multicolour_mode_ = value & 0x10;
+				columns_40_ = value & 8;
+				x_scroll_ = value & 7;
+			break;
+
+			case 0xff12:
+				character_generator_address_ = uint16_t((value & 0xfc) << 8);
+			break;
+			case 0xff14:
+				screen_memory_address_ = uint16_t((value & 0xf8) << 8);
+			break;
+
+			case 0xff0c:	load_high10(cursor_address_);			break;
+			case 0xff0d:	load_low8(cursor_address_);				break;
+			case 0xff1a:	load_high10(character_row_address_);	break;
+			case 0xff1b:	load_low8(character_row_address_);		break;
+		}
+	}
+
+private:
+	bool extended_colour_mode_ = false;
+	bool bitmap_mode_ = false;
+	bool display_enable_ = false;
+	bool rows_25_ = false;
+	int y_scroll_ = 0;
+
+	bool characters_256_ = false;
+	bool is_ntsc_ = false;
+	bool ted_off_ = false;
+	bool multicolour_mode_ = false;
+	bool columns_40_ = false;
+	int x_scroll_ = 0;
+
+	uint16_t cursor_address_ = 0;
+	uint16_t character_row_address_ = 0;
+	uint16_t character_generator_address_ = 0;
+	uint16_t screen_memory_address_ = 0;
+};
+
+}
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 5fd7733d7..f723807c1 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -1296,6 +1296,7 @@
 		42EB812C2B47008D00429AF4 /* MemoryMap.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = MemoryMap.cpp; sourceTree = "<group>"; };
 		4B018B88211930DE002A3937 /* 65C02_extended_opcodes_test.bin */ = {isa = PBXFileReference; lastKnownFileType = archive.macbinary; name = 65C02_extended_opcodes_test.bin; path = "Klaus Dormann/65C02_extended_opcodes_test.bin"; sourceTree = "<group>"; };
 		4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Z80MemptrTests.swift; sourceTree = "<group>"; };
+		4B03291F2D0923E300C51EB5 /* Video.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Video.hpp; sourceTree = "<group>"; };
 		4B0333AD2094081A0050B93D /* AppleDSK.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = AppleDSK.cpp; sourceTree = "<group>"; };
 		4B0333AE2094081A0050B93D /* AppleDSK.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = AppleDSK.hpp; sourceTree = "<group>"; };
 		4B046DC31CFE651500E9E45E /* ScanProducer.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = ScanProducer.hpp; sourceTree = "<group>"; };
@@ -3393,6 +3394,7 @@
 			children = (
 				4B596EAF2D037E8800FBF4B1 /* Plus4.hpp */,
 				4B596EB02D037E8800FBF4B1 /* Plus4.cpp */,
+				4B03291F2D0923E300C51EB5 /* Video.hpp */,
 			);
 			path = Plus4;
 			sourceTree = "<group>";