From 18631399ad3e6987cf4c85c543dce2f969f87b12 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 5 Oct 2021 15:38:56 -0700
Subject: [PATCH] Attempts to clock the disk controller.

---
 Machines/Amiga/Chipset.cpp | 18 ++++++++++++++++++
 Machines/Amiga/Chipset.hpp | 11 +++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/Machines/Amiga/Chipset.cpp b/Machines/Amiga/Chipset.cpp
index 6c64cfff5..1853ead29 100644
--- a/Machines/Amiga/Chipset.cpp
+++ b/Machines/Amiga/Chipset.cpp
@@ -15,6 +15,7 @@
 #include <algorithm>
 #include <cassert>
 
+
 using namespace Amiga;
 
 namespace {
@@ -43,6 +44,7 @@ Chipset::Chipset(MemoryMap &map, int input_clock_rate) :
 	cia_b_handler_(disk_controller_),
 	cia_a(cia_a_handler_),
 	cia_b(cia_b_handler_) {
+	disk_controller_.set_clocking_hint_observer(this);
 }
 
 Chipset::Changes Chipset::run_for(HalfCycles length) {
@@ -412,10 +414,19 @@ template <bool stop_on_cpu> Chipset::Changes Chipset::run(HalfCycles length) {
 		cia_b.run_for(e_clocks);
 	}
 
+	// Propagate TOD updates to the CIAs, and feed their new interrupt
+	// outputs back to here.
 	cia_a.advance_tod(vsyncs);
 	cia_b.advance_tod(hsyncs);
 	set_cia_interrupts(cia_a.get_interrupt_line(), cia_b.get_interrupt_line());
 
+	// Update the disk controller, if any drives are active.
+	if(!disk_controller_is_sleeping_) {
+		disk_controller_.run_for(changes.duration.cycles());
+	}
+
+	// Record the interrupt level.
+	// TODO: is this useful?
 	changes.interrupt_level = interrupt_level_;
 	return changes;
 }
@@ -994,6 +1005,13 @@ uint8_t Chipset::CIABHandler::get_port_input(MOS::MOS6526::Port) {
 	return 0xff;
 }
 
+// MARK: - ClockingHintObserver.
+
+void Chipset::set_component_prefers_clocking(ClockingHint::Source *, ClockingHint::Preference preference) {
+	disk_controller_is_sleeping_ = preference == ClockingHint::Preference::None;
+	LOG("Disk controller is " << (disk_controller_is_sleeping_ ? "sleeping" : "awake"));
+}
+
 // MARK: - Disk Controller.
 
 Chipset::DiskController::DiskController(Cycles clock_rate) :
diff --git a/Machines/Amiga/Chipset.hpp b/Machines/Amiga/Chipset.hpp
index 675461941..88e589e3e 100644
--- a/Machines/Amiga/Chipset.hpp
+++ b/Machines/Amiga/Chipset.hpp
@@ -13,6 +13,7 @@
 #include <cstdint>
 
 #include "../../Activity/Source.hpp"
+#include "../../ClockReceiver/ClockingHintSource.hpp"
 #include "../../Components/6526/6526.hpp"
 #include "../../Outputs/CRT/CRT.hpp"
 #include "../../Processors/68000/68000.hpp"
@@ -59,7 +60,7 @@ enum class DMAFlag: uint16_t {
 	BlitterBusy				= 1 << 14,
 };
 
-class Chipset {
+class Chipset: private ClockingHint::Observer {
 	public:
 		Chipset(MemoryMap &memory_map, int input_clock_rate);
 
@@ -218,13 +219,17 @@ class Chipset {
 
 		// MARK: - Disk drives.
 
-		class DiskController: private Storage::Disk::Controller {
+		class DiskController: public Storage::Disk::Controller {
 			public:
 				DiskController(Cycles clock_rate);
 
 				void set_mtr_sel_side_dir_step(uint8_t);
 				uint8_t get_rdy_trk0_wpro_chng();
 
+				void run_for(Cycles duration) {
+					Storage::Disk::Controller::run_for(duration);
+				}
+
 			private:
 				void process_input_bit(int value) final;
 				void process_index_hole() final;
@@ -235,6 +240,8 @@ class Chipset {
 				uint32_t previous_select_ = 0;
 
 		} disk_controller_;
+		void set_component_prefers_clocking(ClockingHint::Source *, ClockingHint::Preference) final;
+		bool disk_controller_is_sleeping_ = false;
 
 		class DiskDMA: public DMADevice<1> {
 			public: