From fdf2b9cd7b44907181fddc1e0252adce8cd91cb9 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 4 Dec 2021 17:58:41 -0500
Subject: [PATCH] Add local data pointers.

---
 Machines/Amiga/Audio.cpp | 16 +++++++++++-----
 Machines/Amiga/Audio.hpp |  6 ++++++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/Machines/Amiga/Audio.cpp b/Machines/Amiga/Audio.cpp
index bad03caf1..3c2520911 100644
--- a/Machines/Amiga/Audio.cpp
+++ b/Machines/Amiga/Audio.cpp
@@ -27,6 +27,7 @@ Audio::Audio(Chipset &chipset, uint16_t *ram, size_t word_size, float output_rat
 	}
 
 	speaker_.set_input_rate(output_rate);
+	speaker_.set_high_frequency_cutoff(7000.0f);
 }
 
 // MARK: - Exposed setters.
@@ -76,9 +77,12 @@ bool Audio::advance_dma(int channel) {
 		return false;
 	}
 
-	set_data(channel, ram_[pointer_[size_t(channel) & ram_mask_]]);
-	if(channels_[channel].state != Channel::State::WaitingForDummyDMA) {
-		++pointer_[size_t(channel)];
+	set_data(channel, ram_[channels_[channel].data_address & ram_mask_]);
+	++channels_[channel].data_address;
+
+	if(channels_[channel].should_reload_address) {
+		channels_[channel].data_address = pointer_[size_t(channel)];
+		channels_[channel].should_reload_address = false;
 	}
 
 	return true;
@@ -342,9 +346,10 @@ template <> bool Audio::Channel::transit<
 	Audio::Channel::State::PlayingHigh>() {
 	begin_state<State::PlayingHigh>();
 
-	data_latch = data;			// i.e. pbufld1
+	data_latch = data;				// i.e. pbufld1
 	wants_data = true;
-	period_counter = period;	// i.e. percntrld
+	period_counter = period;		// i.e. percntrld
+	should_reload_address = true;	// i.e. dmasen
 	// TODO: volcntrld (see above).
 
 	// Request an interrupt.
@@ -447,6 +452,7 @@ template <> bool Audio::Channel::transit<
 		if(!length_counter) {
 			length_counter = length;
 			will_request_interrupt = true;
+			should_reload_address = true;	// ???
 		}
 	}
 
diff --git a/Machines/Amiga/Audio.hpp b/Machines/Amiga/Audio.hpp
index 3683e057d..685ef48c0 100644
--- a/Machines/Amiga/Audio.hpp
+++ b/Machines/Amiga/Audio.hpp
@@ -70,6 +70,12 @@ class Audio: public DMADevice<4> {
 			bool wants_data = false;
 			uint16_t data_latch = 0x0000;
 
+			// The DMA address; unlike most of the Amiga Chipset,
+			// the user posts a value to feed a pointer, rather
+			// than having access to the pointer itself.
+			bool should_reload_address = false;
+			uint32_t data_address = 0x0000'0000;
+
 			// Number of words remaining in DMA data.
 			uint16_t length = 0;
 			uint16_t length_counter = 0;