/** @file CPUID Leaf 0x15 for Core Crystal Clock frequency instance as Base Timer Library. Copyright (c) 2019 Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent **/ #include #include #include /** CPUID Leaf 0x15 for Core Crystal Clock Frequency. The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX. In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported. @return The number of TSC counts per second. **/ UINT64 CpuidCoreClockCalculateTscFrequency ( VOID ); /** Internal function to retrieves the 64-bit frequency in Hz. Internal function to retrieves the 64-bit frequency in Hz. @return The frequency in Hz. **/ UINT64 InternalGetPerformanceCounterFrequency ( VOID ) { return CpuidCoreClockCalculateTscFrequency (); }