// SPDX-License-Identifier: MIT
#include <FEXCore/Utils/SpinWaitLock.h>

namespace FEXCore::Utils::SpinWaitLock {
#ifdef ARCHITECTURE_arm64
constexpr uint64_t NanosecondsInSecond = 1'000'000'000ULL;

static uint64_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;
}

uint64_t CycleCounterFrequency = GetCycleCounterFrequency();
uint64_t CyclesPerNanosecond = CalculateCyclesPerNanosecond();
#endif
} // namespace FEXCore::Utils::SpinWaitLock