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Last change
on this file since 85788 was 80721, checked in by vboxsync, 6 years ago |
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Devices/EFI/FirmwareNew: Start upgrade process to edk2-stable201908 (compiles on Windows and works to some extent), bugref:4643
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Property svn:eol-style
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File size:
946 bytes
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| 1 | /** @file
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| 2 | CPUID Leaf 0x15 for Core Crystal Clock frequency instance as Base Timer Library.
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| 3 |
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| 4 | Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
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| 5 | SPDX-License-Identifier: BSD-2-Clause-Patent
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| 6 |
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| 7 | **/
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| 8 |
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| 9 | #include <Base.h>
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| 10 | #include <Library/TimerLib.h>
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| 11 | #include <Library/BaseLib.h>
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| 12 |
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| 13 | /**
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| 14 | CPUID Leaf 0x15 for Core Crystal Clock Frequency.
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| 15 |
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| 16 | The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX.
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| 17 | In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported.
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| 18 | @return The number of TSC counts per second.
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| 19 |
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| 20 | **/
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| 21 | UINT64
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| 22 | CpuidCoreClockCalculateTscFrequency (
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| 23 | VOID
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| 24 | );
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| 25 |
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| 26 | /**
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| 27 | Internal function to retrieves the 64-bit frequency in Hz.
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| 28 |
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| 29 | Internal function to retrieves the 64-bit frequency in Hz.
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| 30 |
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| 31 | @return The frequency in Hz.
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| 32 |
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| 33 | **/
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| 34 | UINT64
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| 35 | InternalGetPerformanceCounterFrequency (
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| 36 | VOID
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| 37 | )
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| 38 | {
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| 39 | return CpuidCoreClockCalculateTscFrequency ();
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| 40 | }
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| 41 |
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