Add system::initCpuFlags(). Call it by all new threads.

adapters/standalone.cpp

@@ -129,6 +129,7 @@ int main(int argc, char* argv[]) {
 
 	// Initialize environment
 	system::init();
+	system::initCpuFlags();
 	asset::init();
 	if (!settings::devMode) {
 		logger::logPath = asset::user("log.txt");

include/system.hpp

@@ -196,6 +196,9 @@ The launched process will continue running if the current process is closed.
 void runProcessDetached(const std::string& path);
 
 PRIVATE void init();
+/** Sets Rack-recommended CPU flags for the current thread.
+*/
+void initCpuFlags();
 
 
 } // namespace system

src/engine/Engine.cpp

@@ -21,24 +21,6 @@ namespace rack {
 namespace engine {
 
 
-static void initCpu() {
-	// Set CPU to flush-to-zero (FTZ) and denormals-are-zero (DAZ) mode
-	// https://software.intel.com/en-us/node/682949
-	// On ARM64, this is a SIMDe function.
-	_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
-	// ARM64 always uses DAZ
-#if defined ARCH_X64
-	_MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
-#endif
-
-	// Reset rounding mode
-#if !defined _MM_ROUND_NEAREST
-	#define _MM_ROUND_NEAREST 0x0000
-#endif
-	_MM_SET_ROUNDING_MODE(_MM_ROUND_NEAREST);
-}
-
-
 /** Barrier based on mutexes.
 Not finished or tested, do not use.
 */
@@ -495,7 +477,7 @@ void Engine::stepBlock(int frames) {
 	SharedLock<SharedMutex> lock(internal->mutex);
 	// Configure thread
 	uint32_t csr = _mm_getcsr();
-	initCpu();
+	system::initCpuFlags();
 	random::init();
 
 	internal->blockFrame = internal->frame;
@@ -1289,7 +1271,7 @@ void EngineWorker::run() {
 	// Configure thread
 	contextSet(engine->internal->context);
 	system::setThreadName(string::f("Worker %d", id));
-	initCpu();
+	system::initCpuFlags();
 	random::init();
 
 	while (true) {

src/system.cpp

@@ -1,6 +1,7 @@
 #include <thread>
 #include <regex>
 #include <chrono>
+#include <cfenv> // for std::fesetround
 #include <ghc/filesystem.hpp>
 
 #include <dirent.h>
@@ -38,6 +39,7 @@
 
 #include <system.hpp>
 #include <string.hpp>
+#include <simd/common.hpp>
 
 
 /*
@@ -955,5 +957,20 @@ void init() {
 }
 
 
+void initCpuFlags() {
+	// Set CPU to flush-to-zero (FTZ) and denormals-are-zero (DAZ) mode
+	// https://software.intel.com/en-us/node/682949
+	// On ARM64, this is a SIMDe function.
+	_MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
+	// ARM64 always uses DAZ
+#if defined ARCH_X64
+	_MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
+#endif
+
+	// Reset rounding mode to default (nearest)
+	std::fesetround(FE_TONEAREST);
+}
+
+
 } // namespace system
 } // namespace rack