Use RAII when handling the mixer's FPU state

6 files changed, 47 insertions, 61 deletions

diff --git a/Alc/alc.cpp b/Alc/alc.cpp
index 5c46b950..d9fa549a 100644
--- a/Alc/alc.cpp
+++ b/Alc/alc.cpp
@@ -2241,7 +2241,7 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const ALCint *attrList)
      * allocated with the appropriate size.
      */
     update_failed = AL_FALSE;
-    START_MIXER_MODE();
+    FPUCtl mixer_mode{};
     context = device->ContextList.load();
     while(context)
     {
@@ -2354,7 +2354,7 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const ALCint *attrList)
 
         context = context->next.load(std::memory_order_relaxed);
     }
-    END_MIXER_MODE();
+    mixer_mode.leave();
     if(update_failed)
         return ALC_INVALID_DEVICE;
 
diff --git a/Alc/alu.cpp b/Alc/alu.cpp
index faa011a2..b3ffd24b 100644
--- a/Alc/alu.cpp
+++ b/Alc/alu.cpp
@@ -1697,7 +1697,7 @@ void aluMixData(ALCdevice *device, ALvoid *OutBuffer, ALsizei NumSamples)
     ALCcontext *ctx;
     ALsizei i, c;
 
-    START_MIXER_MODE();
+    FPUCtl mixer_mode{};
     for(SamplesDone = 0;SamplesDone < NumSamples;)
     {
         SamplesToDo = mini(NumSamples-SamplesDone, BUFFERSIZE);
@@ -1815,7 +1815,6 @@ void aluMixData(ALCdevice *device, ALvoid *OutBuffer, ALsizei NumSamples)
 
         SamplesDone += SamplesToDo;
     }
-    END_MIXER_MODE();
 }
 
 
diff --git a/Alc/converter.cpp b/Alc/converter.cpp
index d64bc328..72015db0 100644
--- a/Alc/converter.cpp
+++ b/Alc/converter.cpp
@@ -154,7 +154,7 @@ SampleConverter *CreateSampleConverter(enum DevFmtType srcType, enum DevFmtType
     converter->mFracOffset = 0;
 
     /* Have to set the mixer FPU mode since that's what the resampler code expects. */
-    START_MIXER_MODE();
+    FPUCtl mixer_mode{};
     step = (ALsizei)mind(((ALdouble)srcRate/dstRate*FRACTIONONE) + 0.5,
                          MAX_PITCH * FRACTIONONE);
     converter->mIncrement = maxi(step, 1);
@@ -166,7 +166,6 @@ SampleConverter *CreateSampleConverter(enum DevFmtType srcType, enum DevFmtType
         BsincPrepare(converter->mIncrement, &converter->mState.bsinc, &bsinc12);
         converter->mResample = SelectResampler(BSinc12Resampler);
     }
-    END_MIXER_MODE();
 
     return converter;
 }
@@ -227,7 +226,7 @@ ALsizei SampleConverterInput(SampleConverter *converter, const ALvoid **src, ALs
     const ALsizei increment = converter->mIncrement;
     ALsizei pos = 0;
 
-    START_MIXER_MODE();
+    FPUCtl mixer_mode{};
     while(pos < dstframes && *srcframes > 0)
     {
         ALfloat *RESTRICT SrcData = converter->mSrcSamples;
@@ -339,7 +338,6 @@ ALsizei SampleConverterInput(SampleConverter *converter, const ALvoid **src, ALs
         dst = (ALbyte*)dst + DstFrameSize*DstSize;
         pos += DstSize;
     }
-    END_MIXER_MODE();
 
     return pos;
 }
diff --git a/Alc/fpu_modes.h b/Alc/fpu_modes.h
index e8858ad9..1afd6618 100644
--- a/Alc/fpu_modes.h
+++ b/Alc/fpu_modes.h
@@ -1,41 +1,25 @@
 #ifndef FPU_MODES_H
 #define FPU_MODES_H
 
-#ifdef HAVE_FENV_H
-#include <fenv.h>
-#endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-typedef struct FPUCtl {
+class FPUCtl {
 #if defined(__GNUC__) && defined(HAVE_SSE)
-    unsigned int sse_state;
+    unsigned int sse_state{};
 #elif defined(HAVE___CONTROL87_2)
-    unsigned int state;
-    unsigned int sse_state;
+    unsigned int state{};
+    unsigned int sse_state{};
 #elif defined(HAVE__CONTROLFP)
-    unsigned int state;
+    unsigned int state{};
 #endif
-} FPUCtl;
-void SetMixerFPUMode(FPUCtl *ctl);
-void RestoreFPUMode(const FPUCtl *ctl);
+    bool in_mode{};
 
-#ifdef __GNUC__
-/* Use an alternate macro set with GCC to avoid accidental continue or break
- * statements within the mixer mode.
- */
-#define START_MIXER_MODE() __extension__({ FPUCtl _oldMode; SetMixerFPUMode(&_oldMode)
-#define END_MIXER_MODE() RestoreFPUMode(&_oldMode); })
-#else
-#define START_MIXER_MODE() do { FPUCtl _oldMode; SetMixerFPUMode(&_oldMode)
-#define END_MIXER_MODE() RestoreFPUMode(&_oldMode); } while(0)
-#endif
-#define LEAVE_MIXER_MODE() RestoreFPUMode(&_oldMode)
+public:
+    FPUCtl() noexcept;
+    ~FPUCtl() { leave(); }
 
-#ifdef __cplusplus
-} // extern "C"
-#endif
+    FPUCtl(const FPUCtl&) = delete;
+    FPUCtl& operator=(const FPUCtl&) = delete;
+
+    void leave() noexcept;
+};
 
 #endif /* FPU_MODES_H */
diff --git a/Alc/helpers.cpp b/Alc/helpers.cpp
index a78e3d83..658c7d09 100644
--- a/Alc/helpers.cpp
+++ b/Alc/helpers.cpp
@@ -260,13 +260,13 @@ void FillCPUCaps(int capfilter)
 }
 
 
-void SetMixerFPUMode(FPUCtl *ctl)
+FPUCtl::FPUCtl() noexcept
 {
 #if defined(__GNUC__) && defined(HAVE_SSE)
     if((CPUCapFlags&CPU_CAP_SSE))
     {
-        __asm__ __volatile__("stmxcsr %0" : "=m" (*&ctl->sse_state));
-        unsigned int sseState = ctl->sse_state;
+        __asm__ __volatile__("stmxcsr %0" : "=m" (*&this->sse_state));
+        unsigned int sseState = this->sse_state;
         sseState |= 0x8000; /* set flush-to-zero */
         if((CPUCapFlags&CPU_CAP_SSE2))
             sseState |= 0x0040; /* set denormals-are-zero */
@@ -275,32 +275,37 @@ void SetMixerFPUMode(FPUCtl *ctl)
 
 #elif defined(HAVE___CONTROL87_2)
 
-    __control87_2(0, 0, &ctl->state, &ctl->sse_state);
+    __control87_2(0, 0, &this->state, &this->sse_state);
     _control87(_DN_FLUSH, _MCW_DN);
 
 #elif defined(HAVE__CONTROLFP)
 
-    ctl->state = _controlfp(0, 0);
+    this->state = _controlfp(0, 0);
     _controlfp(_DN_FLUSH, _MCW_DN);
 #endif
+
+    this->in_mode = true;
 }
 
-void RestoreFPUMode(const FPUCtl *ctl)
+void FPUCtl::leave() noexcept
 {
+    if(!this->in_mode) return;
+
 #if defined(__GNUC__) && defined(HAVE_SSE)
     if((CPUCapFlags&CPU_CAP_SSE))
-        __asm__ __volatile__("ldmxcsr %0" : : "m" (*&ctl->sse_state));
+        __asm__ __volatile__("ldmxcsr %0" : : "m" (*&this->sse_state));
 
 #elif defined(HAVE___CONTROL87_2)
 
     unsigned int mode;
-    __control87_2(ctl->state, _MCW_DN, &mode, nullptr);
-    __control87_2(ctl->sse_state, _MCW_DN, nullptr, &mode);
+    __control87_2(this->state, _MCW_DN, &mode, nullptr);
+    __control87_2(this->sse_state, _MCW_DN, nullptr, &mode);
 
 #elif defined(HAVE__CONTROLFP)
 
-    _controlfp(ctl->state, _MCW_DN);
+    _controlfp(this->state, _MCW_DN);
 #endif
+    this->in_mode = false;
 }
 
 
diff --git a/OpenAL32/alAuxEffectSlot.cpp b/OpenAL32/alAuxEffectSlot.cpp
index df2c2a43..60c44f49 100644
--- a/OpenAL32/alAuxEffectSlot.cpp
+++ b/OpenAL32/alAuxEffectSlot.cpp
@@ -514,19 +514,19 @@ ALenum InitializeEffect(ALCcontext *Context, ALeffectslot *EffectSlot, ALeffect
         EffectState *State{factory->create()};
         if(!State) return AL_OUT_OF_MEMORY;
 
-        START_MIXER_MODE(); {
-            ALCdevice *Device{Context->Device};
-            std::unique_lock<almtx_t> backlock{Device->BackendLock};
-            State->mOutBuffer = Device->Dry.Buffer;
-            State->mOutChannels = Device->Dry.NumChannels;
-            if(State->deviceUpdate(Device) == AL_FALSE)
-            {
-                backlock.unlock();
-                LEAVE_MIXER_MODE();
-                State->DecRef();
-                return AL_OUT_OF_MEMORY;
-            }
-        } END_MIXER_MODE();
+        FPUCtl mixer_mode{};
+        ALCdevice *Device{Context->Device};
+        std::unique_lock<almtx_t> backlock{Device->BackendLock};
+        State->mOutBuffer = Device->Dry.Buffer;
+        State->mOutChannels = Device->Dry.NumChannels;
+        if(State->deviceUpdate(Device) == AL_FALSE)
+        {
+            backlock.unlock();
+            mixer_mode.leave();
+            State->DecRef();
+            return AL_OUT_OF_MEMORY;
+        }
+        mixer_mode.leave();
 
         if(!effect)
         {