From 7b376abd3bd59eeeeddb3cdb6f0000e8c901ba1e Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Sat, 9 May 2015 23:50:45 -0400
Subject: [PATCH] Mixer: Convert volatile variables to atomics.

---
 Source/Core/AudioCommon/Mixer.cpp | 23 ++++++++++-------------
 Source/Core/AudioCommon/Mixer.h   | 15 ++++++++-------
 2 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/Source/Core/AudioCommon/Mixer.cpp b/Source/Core/AudioCommon/Mixer.cpp
index 90f771d3fa..90fcbd06ae 100644
--- a/Source/Core/AudioCommon/Mixer.cpp
+++ b/Source/Core/AudioCommon/Mixer.cpp
@@ -4,7 +4,6 @@
 
 #include "AudioCommon/AudioCommon.h"
 #include "AudioCommon/Mixer.h"
-#include "Common/Atomic.h"
 #include "Common/CPUDetect.h"
 #include "Common/MathUtil.h"
 #include "Core/ConfigManager.h"
@@ -31,8 +30,8 @@ unsigned int CMixer::MixerFifo::Mix(short* samples, unsigned int numSamples, boo
 	// so we will just ignore new written data while interpolating.
 	// Without this cache, the compiler wouldn't be allowed to optimize the
 	// interpolation loop.
-	u32 indexR = Common::AtomicLoad(m_indexR);
-	u32 indexW = Common::AtomicLoad(m_indexW);
+	u32 indexR = m_indexR.load();
+	u32 indexW = m_indexW.load();
 
 	float numLeft = (float)(((indexW - indexR) & INDEX_MASK) / 2);
 	m_numLeftI = (numLeft + m_numLeftI*(CONTROL_AVG-1)) / CONTROL_AVG;
@@ -53,8 +52,8 @@ unsigned int CMixer::MixerFifo::Mix(short* samples, unsigned int numSamples, boo
 
 	const u32 ratio = (u32)(65536.0f * aid_sample_rate / (float)m_mixer->m_sampleRate);
 
-	s32 lvolume = m_LVolume;
-	s32 rvolume = m_RVolume;
+	s32 lvolume = m_LVolume.load();
+	s32 rvolume = m_RVolume.load();
 
 	// TODO: consider a higher-quality resampling algorithm.
 	for (; currentSample < numSamples * 2 && ((indexW-indexR) & INDEX_MASK) > 2; currentSample += 2)
@@ -99,7 +98,7 @@ unsigned int CMixer::MixerFifo::Mix(short* samples, unsigned int numSamples, boo
 	}
 
 	// Flush cached variable
-	Common::AtomicStore(m_indexR, indexR);
+	m_indexR.store(indexR);
 
 	return numSamples;
 }
@@ -130,11 +129,11 @@ void CMixer::MixerFifo::PushSamples(const short *samples, unsigned int num_sampl
 	// Cache access in non-volatile variable
 	// indexR isn't allowed to cache in the audio throttling loop as it
 	// needs to get updates to not deadlock.
-	u32 indexW = Common::AtomicLoad(m_indexW);
+	u32 indexW = m_indexW.load();
 
 	// Check if we have enough free space
 	// indexW == m_indexR results in empty buffer, so indexR must always be smaller than indexW
-	if (num_samples * 2 + ((indexW - Common::AtomicLoad(m_indexR)) & INDEX_MASK) >= MAX_SAMPLES * 2)
+	if (num_samples * 2 + ((indexW - m_indexR.load()) & INDEX_MASK) >= MAX_SAMPLES * 2)
 		return;
 
 	// AyuanX: Actual re-sampling work has been moved to sound thread
@@ -151,9 +150,7 @@ void CMixer::MixerFifo::PushSamples(const short *samples, unsigned int num_sampl
 		memcpy(&m_buffer[indexW & INDEX_MASK], samples, num_samples * 4);
 	}
 
-	Common::AtomicAdd(m_indexW, num_samples * 2);
-
-	return;
+	m_indexW.fetch_add(num_samples * 2);
 }
 
 void CMixer::PushSamples(const short *samples, unsigned int num_samples)
@@ -215,6 +212,6 @@ void CMixer::MixerFifo::SetInputSampleRate(unsigned int rate)
 
 void CMixer::MixerFifo::SetVolume(unsigned int lvolume, unsigned int rvolume)
 {
-	m_LVolume = lvolume + (lvolume >> 7);
-	m_RVolume = rvolume + (rvolume >> 7);
+	m_LVolume.store(lvolume + (lvolume >> 7));
+	m_RVolume.store(rvolume + (rvolume >> 7));
 }
diff --git a/Source/Core/AudioCommon/Mixer.h b/Source/Core/AudioCommon/Mixer.h
index ba9809d5bc..cc73b95406 100644
--- a/Source/Core/AudioCommon/Mixer.h
+++ b/Source/Core/AudioCommon/Mixer.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <atomic>
 #include <mutex>
 #include <string>
 
@@ -109,8 +110,8 @@ public:
 
 	std::mutex& MixerCritical() { return m_csMixing; }
 
-	float GetCurrentSpeed() const { return m_speed; }
-	void UpdateSpeed(volatile float val) { m_speed = val; }
+	float GetCurrentSpeed() const { return m_speed.load(); }
+	void UpdateSpeed(float val) { m_speed.store(val); }
 
 protected:
 	class MixerFifo {
@@ -135,11 +136,11 @@ protected:
 		CMixer *m_mixer;
 		unsigned m_input_sample_rate;
 		short m_buffer[MAX_SAMPLES * 2];
-		volatile u32 m_indexW;
-		volatile u32 m_indexR;
+		std::atomic<u32> m_indexW;
+		std::atomic<u32> m_indexR;
 		// Volume ranges from 0-256
-		volatile s32 m_LVolume;
-		volatile s32 m_RVolume;
+		std::atomic<s32> m_LVolume;
+		std::atomic<s32> m_RVolume;
 		float m_numLeftI;
 		u32 m_frac;
 	};
@@ -156,5 +157,5 @@ protected:
 
 	std::mutex m_csMixing;
 
-	volatile float m_speed; // Current rate of the emulation (1.0 = 100% speed)
+	std::atomic<float> m_speed; // Current rate of the emulation (1.0 = 100% speed)
 };