From 908878e45d3f13215f06f25b2700ec1dfda32efe Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Wed, 18 Aug 2021 10:52:45 -0400
Subject: [PATCH] Save and restore MXCSR back to original value in
 Engine::stepBlock().

---
 src/engine/Engine.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 397c17b3..04c9c2a0 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -564,7 +564,10 @@ void Engine::stepBlock(int frames) {
 	std::lock_guard<std::mutex> stepLock(internal->blockMutex);
 	ReadLock lock(internal->mutex);
 	// Configure thread
+	uint32_t csr = _mm_getcsr();
+	DEBUG("original MXCSR %x", csr);
 	initMXCSR();
+	DEBUG("new MXCSR %x", csr);
 	random::init();
 
 	internal->blockFrame = internal->frame;
@@ -606,6 +609,9 @@ void Engine::stepBlock(int frames) {
 		internal->meterTotal = 0.0;
 		internal->meterMax = 0.0;
 	}
+
+	// Reset MXCSR back to original value
+	_mm_setcsr(csr);
 }