From 2ac2a39a214decb16ec5193eaafdb4a30bc976c1 Mon Sep 17 00:00:00 2001
From: hogliux <fabian.renn@gmail.com>
Date: Tue, 17 Oct 2017 09:57:39 +0100
Subject: [PATCH] Added disableDenormalisedNumberSupport to query if denormals
 are disabled and improved documentation

---
 .../buffers/juce_FloatVectorOperations.cpp    | 21 +++++++++++++++++--
 .../buffers/juce_FloatVectorOperations.h      | 15 +++++++------
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.cpp b/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.cpp
index 86933ba6c4..4dc3a86d85 100644
--- a/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.cpp
+++ b/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.cpp
@@ -1084,7 +1084,7 @@ void JUCE_CALLTYPE FloatVectorOperations::enableFlushToZeroMode (bool shouldEnab
   #endif
 }
 
-void JUCE_CALLTYPE FloatVectorOperations::disableDenormalisedNumberSupport() noexcept
+void JUCE_CALLTYPE FloatVectorOperations::disableDenormalisedNumberSupport (bool shouldDisable) noexcept
 {
   #if JUCE_USE_SSE_INTRINSICS || (JUCE_USE_ARM_NEON || defined (__arm64__) || defined (__aarch64__))
    #if JUCE_USE_SSE_INTRINSICS
@@ -1093,14 +1093,31 @@ void JUCE_CALLTYPE FloatVectorOperations::disableDenormalisedNumberSupport() noe
     intptr_t mask = (1 << 24 /* FZ */);
    #endif
 
-    setFpStatusRegister (getFpStatusRegister() | mask);
+    setFpStatusRegister ((getFpStatusRegister() & (~mask)) | (shouldDisable ? mask : 0));
   #else
+    ignoreUnused (shouldDisable);
+
    #if ! (defined (JUCE_INTEL) || defined (JUCE_ARM))
     jassertfalse; // No support for disable denormals mode on your platform
    #endif
   #endif
 }
 
+bool JUCE_CALLTYPE FloatVectorOperations::areDenormalsDisabled() noexcept
+{
+  #if JUCE_USE_SSE_INTRINSICS || (JUCE_USE_ARM_NEON || defined (__arm64__) || defined (__aarch64__))
+   #if JUCE_USE_SSE_INTRINSICS
+    intptr_t mask = 0x8040;
+   #else /*JUCE_USE_ARM_NEON*/
+    intptr_t mask = (1 << 24 /* FZ */);
+   #endif
+
+    return ((getFpStatusRegister() & mask) == mask);
+  #else
+    return false;
+  #endif
+}
+
 ScopedNoDenormals::ScopedNoDenormals() noexcept
 {
   #if JUCE_USE_SSE_INTRINSICS || (JUCE_USE_ARM_NEON || defined (__arm64__) || defined (__aarch64__))
diff --git a/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.h b/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.h
index ca5d734691..18f840414d 100644
--- a/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.h
+++ b/modules/juce_audio_basics/buffers/juce_FloatVectorOperations.h
@@ -210,16 +210,19 @@ public:
     /** Finds the maximum value in the given array. */
     static double JUCE_CALLTYPE findMaximum (const double* src, int numValues) noexcept;
 
-    /** On Intel CPUs, this method enables or disables the SSE flush-to-zero mode.
-        Effectively, this is a wrapper around a call to _MM_SET_FLUSH_ZERO_MODE
-    */
+    /** This method enables or disables the SSE/NEON flush-to-zero mode. */
     static void JUCE_CALLTYPE enableFlushToZeroMode (bool shouldEnable) noexcept;
 
     /** On Intel CPUs, this method enables the SSE flush-to-zero and denormalised-are-zero modes.
-        This effectively sets the DAZ and FZ bits of the MXCSR register. It's a convenient thing to
-        call before audio processing code where you really want to avoid denormalisation performance hits.
+        This effectively sets the DAZ and FZ bits of the MXCSR register. On arm CPUs this will
+        enable flush to zero mode.
+        It's a convenient thing to call before audio processing code where you really want to
+        avoid denormalisation performance hits.
     */
-    static void JUCE_CALLTYPE disableDenormalisedNumberSupport() noexcept;
+    static void JUCE_CALLTYPE disableDenormalisedNumberSupport (bool shouldDisable = true) noexcept;
+
+    /** This method returns true if denormals are currently disabled. */
+    static bool JUCE_CALLTYPE areDenormalsDisabled() noexcept;
 
 private:
     friend ScopedNoDenormals;