From 0e0aab88de679927a1ecff980d88727cc5ebd1e6 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Tue, 18 Feb 2025 05:53:54 -0500
Subject: [PATCH] GA20: another optimization

---
 src/engine/platform/sound/ga20/iremga20.cpp | 8 +++++---
 src/engine/platform/sound/ga20/iremga20.h   | 2 ++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/engine/platform/sound/ga20/iremga20.cpp b/src/engine/platform/sound/ga20/iremga20.cpp
index e9af15fa0..182d21e11 100644
--- a/src/engine/platform/sound/ga20/iremga20.cpp
+++ b/src/engine/platform/sound/ga20/iremga20.cpp
@@ -77,6 +77,7 @@ void iremga20_device::device_reset()
 	{
 		m_channel[i].rate = 0;
 		m_channel[i].pos = 0;
+		m_channel[i].sample = 0;
 		m_channel[i].counter = 0;
 		m_channel[i].end = 0;
 		m_channel[i].volume = 0;
@@ -99,17 +100,17 @@ void iremga20_device::sound_stream_update(short** outputs, int len)
 			channel_def &ch = m_channel[j];
 			if (ch.play)
 			{
-				int sample = m_intf.read_byte(ch.pos);
-				if (sample == 0x00) // check for sample end marker
+				if (ch.sample == 0x00) // check for sample end marker
 					ch.play = false;
 				else
 				{
-					sampleout = ch.mute ? 0 : (sample - 0x80) * (s32)ch.volume;
+					sampleout = ch.mute ? 0 : (ch.sample - 0x80) * (s32)ch.volume;
 					ch.counter--;
 					if (ch.counter <= ch.rate)
 					{
 						ch.pos++;
 						ch.counter = 0x100;
+				                ch.sample = m_intf.read_byte(ch.pos);
 					}
 				}
 			}
@@ -150,6 +151,7 @@ void iremga20_device::write(u32 offset, u8 data)
 				m_channel[ch].pos = (m_regs[ch << 3 | 0] | m_regs[ch << 3 | 1] << 8) << 4;
 				m_channel[ch].end = (m_regs[ch << 3 | 2] | m_regs[ch << 3 | 3] << 8) << 4;
 				m_channel[ch].counter = 0x100;
+				                                           m_channel[ch].sample = m_intf.read_byte(m_channel[ch].pos);
 			}
 			else
 				m_channel[ch].play = false;
diff --git a/src/engine/platform/sound/ga20/iremga20.h b/src/engine/platform/sound/ga20/iremga20.h
index 1a27891ec..cfe181397 100644
--- a/src/engine/platform/sound/ga20/iremga20.h
+++ b/src/engine/platform/sound/ga20/iremga20.h
@@ -57,6 +57,7 @@ private:
 	struct channel_def
 	{
 		channel_def() :
+                        sample(0),
 			rate(0),
 			pos(0),
 			counter(0),
@@ -67,6 +68,7 @@ private:
 		{
 		}
 
+                int sample;
 		u32 rate;
 		u32 pos;
 		u32 counter;