From 54352cb1cb572826c9b28503f5b215d2f99af1a4 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 9 Nov 2020 21:54:25 -0500
Subject: [PATCH] Stubs in a couple more registers.

PC now hits $0000. Likely a bug.
---
 Machines/Apple/AppleIIgs/ADB.cpp       |  2 +-
 Machines/Apple/AppleIIgs/AppleIIgs.cpp | 21 +++++++++++++++++++++
 Machines/Apple/AppleIIgs/Video.cpp     |  7 +++++++
 Machines/Apple/AppleIIgs/Video.hpp     |  3 +++
 4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/Machines/Apple/AppleIIgs/ADB.cpp b/Machines/Apple/AppleIIgs/ADB.cpp
index 204201a42..86af5d525 100644
--- a/Machines/Apple/AppleIIgs/ADB.cpp
+++ b/Machines/Apple/AppleIIgs/ADB.cpp
@@ -87,7 +87,7 @@ uint8_t GLU::get_status() {
 	// b0:	1 = command register is full (set when command is written); 0 = empty (cleared when data is read).
 	const uint8_t status =
 		(pending_response_.empty() ? 0 : 0x20);	// Data is valid if a response is pending.
-	printf("ADB get status : %02x\n", status);
+//	printf("ADB get status : %02x\n", status);
 	return status;
 }
 
diff --git a/Machines/Apple/AppleIIgs/AppleIIgs.cpp b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
index 56451dde8..380e569ff 100644
--- a/Machines/Apple/AppleIIgs/AppleIIgs.cpp
+++ b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
@@ -391,6 +391,26 @@ class ConcreteMachine:
 						// TODO: begin analogue channel charge.
 					break;
 
+					// Monochome/colour register.
+					case 0xc021:
+						// "Uses bit 7 to determine whether composite output is colour 9) or gray scale (1)."
+						if(is_read) {
+							*value = video_->get_composite_is_colour() ? 0x00 : 0x80;
+						} else {
+							video_->set_composite_is_colour(!(*value & 0x80));
+						}
+					break;
+
+					// Language select. (?)
+					case 0xc02b:
+						if(is_read) {
+							*value = language_;
+						} else {
+							language_ = *value;
+						}
+					break;
+
+					// Slot select.
 					case 0xc02d:
 						// b7: 0 = internal ROM code for slot 7;
 						// b6: 0 = internal ROM code for slot 6;
@@ -580,6 +600,7 @@ class ConcreteMachine:
 		uint8_t card_mask_ = 0x00;
 
 		bool test_mode_ = false;
+		uint8_t language_ = 0;
 };
 
 }
diff --git a/Machines/Apple/AppleIIgs/Video.cpp b/Machines/Apple/AppleIIgs/Video.cpp
index f228076ec..c269d69d3 100644
--- a/Machines/Apple/AppleIIgs/Video.cpp
+++ b/Machines/Apple/AppleIIgs/Video.cpp
@@ -281,3 +281,10 @@ void VideoBase::set_text_colour(uint8_t colour) {
 	text_colour_ = appleii_palette[colour >> 4];
 	background_colour_ = appleii_palette[colour & 0xf];
 }
+
+void VideoBase::set_composite_is_colour(bool) {
+}
+
+bool VideoBase::get_composite_is_colour() {
+	return true;
+}
diff --git a/Machines/Apple/AppleIIgs/Video.hpp b/Machines/Apple/AppleIIgs/Video.hpp
index 52cda9611..ff16d8511 100644
--- a/Machines/Apple/AppleIIgs/Video.hpp
+++ b/Machines/Apple/AppleIIgs/Video.hpp
@@ -41,6 +41,9 @@ class VideoBase: public Apple::II::VideoSwitches<Cycles> {
 		void set_border_colour(uint8_t);
 		void set_text_colour(uint8_t);
 
+		void set_composite_is_colour(bool);
+		bool get_composite_is_colour();
+
 		/// Sets the scan target.
 		void set_scan_target(Outputs::Display::ScanTarget *scan_target);