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28 lines
982 B
C++
28 lines
982 B
C++
// SPDX-License-Identifier: MIT
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#include <FEXCore/Utils/SpinWaitLock.h>
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namespace FEXCore::Utils::SpinWaitLock {
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#ifdef ARCHITECTURE_arm64
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constexpr uint64_t NanosecondsInSecond = 1'000'000'000ULL;
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static uint64_t GetCycleCounterFrequency() {
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uint64_t Result {};
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__asm("mrs %[Res], CNTFRQ_EL0" : [Res] "=r"(Result));
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return Result;
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}
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static uint64_t CalculateCyclesPerNanosecond() {
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// Snapdragon devices historically use a 19.2Mhz cycle counter frequency
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// This means that the number of cycles per nanosecond ends up being 52.0833...
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//
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// ARMv8.6 and ARMv9.1 requires the cycle counter frequency to be 1Ghz.
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// This means the number of cycles per nanosecond ends up being 1.
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uint64_t CounterFrequency = GetCycleCounterFrequency();
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return NanosecondsInSecond / CounterFrequency;
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}
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uint64_t CycleCounterFrequency = GetCycleCounterFrequency();
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uint64_t CyclesPerNanosecond = CalculateCyclesPerNanosecond();
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#endif
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} // namespace FEXCore::Utils::SpinWaitLock
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