From f0e9d39f29b88e8affb1e14b05dcd3051631eb97 Mon Sep 17 00:00:00 2001
From: Fredrik Noring <noring@nocrew.org>
Date: Wed, 15 Jan 2025 18:33:37 +0100
Subject: [PATCH] Provisional check for RAM writes during STE DMA sound
 playback

---
 include/atari/sound.h |  2 ++
 lib/atari/ram.c       |  5 +++++
 lib/atari/sound.c     | 15 +++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/include/atari/sound.h b/include/atari/sound.h
index 30005e2..2a2d42d 100644
--- a/include/atari/sound.h
+++ b/include/atari/sound.h
@@ -78,4 +78,6 @@ extern const struct device sound_device;
 
 void sound_sample(sound_sample_f sample, void *sample_arg);
 
+void sound_check(u32 bus_address);
+
 #endif /* ATARI_SOUND_H */
diff --git a/lib/atari/ram.c b/lib/atari/ram.c
index bf7c8be..ec17c8b 100644
--- a/lib/atari/ram.c
+++ b/lib/atari/ram.c
@@ -9,6 +9,7 @@
 #include "atari/device.h"
 #include "atari/exception-vector.h"
 #include "atari/ram.h"
+#include "atari/sound.h"
 #include "atari/system-variable.h"
 
 static u8 ram[4 * 1024 * 1024];	/* 4 MiB of RAM */
@@ -31,12 +32,16 @@ static u16 ram_rd_u16(const struct device *device, u32 dev_address)
 static void ram_wr_u8(const struct device *device,
 	u32 dev_address, u8 data)
 {
+	sound_check(dev_address);
+
 	ram[dev_address] = data;
 }
 
 static void ram_wr_u16(const struct device *device,
 	u32 dev_address, u16 data)
 {
+	sound_check(dev_address);
+
 	ram[dev_address] = data >> 8;
 	ram[dev_address + 1] = data & 0xff;
 }
diff --git a/lib/atari/sound.c b/lib/atari/sound.c
index a32c1b2..86be270 100644
--- a/lib/atari/sound.c
+++ b/lib/atari/sound.c
@@ -320,6 +320,21 @@ void sound_sample(sound_sample_f sample, void *sample_arg)
 	output.sample_arg = sample_arg;
 }
 
+void sound_check(u32 bus_address)
+{
+	/*
+	 * FIXME: Provisional check for Quartet files such as Spaz that
+	 * write to RAM during DMA playback.
+	 */
+	extern const struct device sound_device;
+	const struct device *device = &sound_device;
+
+	if (state.regs.ctrl.dma &&
+	    state.start <= bus_address &&
+	    bus_address <  state.end)
+		sound_emit(device_cycle(device));
+}
+
 const struct device sound_device = {
 	.name = "snd",
 	.frequency = SOUND_FREQUENCY,