Core/DSPCore: Improve Interpreter address register add/sub, convert to

 assembler for JIT. Replace JIT ToMask() with a different variant. Remove
 superfluous zeroWriteBackLog calls(added by me).
Core/Common: Don't bother creating a string and calling into a Logs trigger()
 when there is noone listening. Change AtomicLoadAcquire for gcc to just
 make the compiler not reorder memory accesses around it instead of doing
 a full memory barrier, per the comment in the win32 variant.
Core/AudioCommon: Fix a use of uninitialized variable inside libalsa.

Microbenchmarking results for ToMask variants:(1 000 000 000 iterations):
             cpu\variant| shifts | bit scan
intel mobile C2D@2.5GHz | 5.5s   | 4.0s
amd athlon64x2@3GHz     | 6.1s   | 6.4s
(including some constant overhead identical to both variants)



git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@6667 8ced0084-cf51-0410-be5f-012b33b47a6e

3 files changed, 8 insertions, 3 deletions

diff --git a/Source/Core/Common/Src/Atomic_GCC.h b/Source/Core/Common/Src/Atomic_GCC.h
index 363cf7a4f7..8eb2f5d818 100644
--- a/Source/Core/Common/Src/Atomic_GCC.h
+++ b/Source/Core/Common/Src/Atomic_GCC.h
@@ -57,8 +57,12 @@ inline u32 AtomicLoad(volatile u32& src) {
 	return src; // 32-bit reads are always atomic.
 }
 inline u32 AtomicLoadAcquire(volatile u32& src) {
-	__sync_synchronize(); // TODO: May not be necessary.
-	return src;
+	//keep the compiler from caching any memory references
+	u32 result = src; // 32-bit reads are always atomic.
+	//__sync_synchronize(); // TODO: May not be necessary.
+	// Compiler instruction only. x86 loads always have acquire semantics.
+	__asm__ __volatile__ ( "":::"memory" );
+	return result;
 }
 
 inline void AtomicOr(volatile u32& target, u32 value) {
diff --git a/Source/Core/Common/Src/LogManager.cpp b/Source/Core/Common/Src/LogManager.cpp
index 651cb01ad2..cdf9a99acb 100644
--- a/Source/Core/Common/Src/LogManager.cpp
+++ b/Source/Core/Common/Src/LogManager.cpp
@@ -116,7 +116,7 @@ void LogManager::Log(LogTypes::LOG_LEVELS level, LogTypes::LOG_TYPE type,
 	char msg[MAX_MSGLEN * 2];
 	LogContainer *log = m_Log[type];
 
-	if (! log->isEnable() || level > log->getLevel())
+	if (! log->isEnable() || level > log->getLevel() || ! log->hasListeners())
 		return;
 
 	CharArrayFromFormatV(temp, MAX_MSGLEN, format, args);
diff --git a/Source/Core/Common/Src/LogManager.h b/Source/Core/Common/Src/LogManager.h
index 7e247925c4..37a0ca3c45 100644
--- a/Source/Core/Common/Src/LogManager.h
+++ b/Source/Core/Common/Src/LogManager.h
@@ -89,6 +89,7 @@ public:
 	void setLevel(LogTypes::LOG_LEVELS level) {
 		m_level = level;
 	}
+	bool hasListeners() const { return listeners.size() > 0; }
 
 private:
 	char m_fullName[128];