From c5e8b547af2ed9edebc3573995ca2829c9a80d82 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 22 Oct 2021 11:21:58 -0700
Subject: [PATCH] Captures the attach flag and observes activation rule.

---
 Machines/Amiga/Chipset.cpp | 3 +++
 Machines/Amiga/Chipset.hpp | 1 +
 2 files changed, 4 insertions(+)

diff --git a/Machines/Amiga/Chipset.cpp b/Machines/Amiga/Chipset.cpp
index 5d44d376c..5e3a7d8da 100644
--- a/Machines/Amiga/Chipset.cpp
+++ b/Machines/Amiga/Chipset.cpp
@@ -911,16 +911,19 @@ void Chipset::Bitplanes::set_control(uint16_t control) {
 void Chipset::Sprite::set_start_position(uint16_t value) {
 	v_start_ = (v_start_ & 0xff00) | (value >> 8);
 	h_start_ = (h_start_ & 0xff00) | ((value & 0xff));
+	active_ = false;
 }
 
 void Chipset::Sprite::set_stop_and_control(uint16_t value) {
 	h_start_ = uint16_t((h_start_ & 0x00ff) | ((value & 0x01) << 8));
 	v_stop_ = uint16_t((value >> 8) | ((value & 0x02) << 7));
 	v_start_ = uint16_t((v_start_ & 0x00ff) | ((value & 0x04) << 6));
+	attached_ = value & 0x80;
 }
 
 void Chipset::Sprite::set_image_data(int slot, uint16_t value) {
 	data_[slot] = value;
+	active_ |= slot == 0;
 }
 
 // MARK: - Disk.
diff --git a/Machines/Amiga/Chipset.hpp b/Machines/Amiga/Chipset.hpp
index e1c1a9b7f..8867235fd 100644
--- a/Machines/Amiga/Chipset.hpp
+++ b/Machines/Amiga/Chipset.hpp
@@ -137,6 +137,7 @@ class Chipset: private ClockingHint::Observer {
 			private:
 				uint16_t v_start_ = 0, h_start_ = 0, v_stop_ = 0;
 				uint16_t data_[2]{};
+				bool active_ = false, attached_ = false;
 		} sprites_[8];
 
 		// MARK: - Raster position and state.