FEXCore/Utils: Rename FutexSpinWait to SpinWaitLock

FEXCore/Source/Utils/SpinWaitLock.cpp

@@ -0,0 +1,27 @@
+#include "Utils/SpinWaitLock.h"
+
+namespace FEXCore::Utils::SpinWaitLock {
+#ifdef _M_ARM_64
+  constexpr uint64_t NanosecondsInSecond = 1'000'000'000ULL;
+
+  static uint32_t GetCycleCounterFrequency() {
+    uint64_t Result{};
+    __asm("mrs %[Res], CNTFRQ_EL0"
+        : [Res] "=r" (Result));
+    return Result;
+  }
+
+  static uint64_t CalculateCyclesPerNanosecond() {
+    // Snapdragon devices historically use a 19.2Mhz cycle counter frequency
+    // This means that the number of cycles per nanosecond ends up being 52.0833...
+    //
+    // ARMv8.6 and ARMv9.1 requires the cycle counter frequency to be 1Ghz.
+    // This means the number of cycles per nanosecond ends up being 1.
+    uint64_t CounterFrequency = GetCycleCounterFrequency();
+    return NanosecondsInSecond / CounterFrequency;
+  }
+
+  uint32_t CycleCounterFrequency = GetCycleCounterFrequency();
+  uint64_t CyclesPerNanosecond = CalculateCyclesPerNanosecond();
+#endif
+}