ReactOS 0.4.15-dev-8222-g9164419
time.c File Reference
#include "bl.h"
Include dependency graph for time.c:

Go to the source code of this file.

Functions

NTSTATUS BlpTimeMeasureTscFrequency (VOID)
 
NTSTATUS BlpTimeCalibratePerformanceCounter (VOID)
 
ULONGLONG BlTimeQueryPerformanceCounter (_Out_opt_ PLARGE_INTEGER Frequency)
 

Variables

ULONGLONG BlpTimePerformanceFrequency
 

Function Documentation

◆ BlpTimeCalibratePerformanceCounter()

NTSTATUS BlpTimeCalibratePerformanceCounter ( VOID  )

Definition at line 62 of file time.c.

65{
66#if defined(_M_IX86) || defined(_M_X64)
67 INT CpuInfo[4];
68
69 /* Check if the ISVM bit it set, meaning we're in a hypervisor */
70 __cpuid(CpuInfo, 1);
71 if (CpuInfo[2] & 0x80000000)
72 {
73 /* Get the Hypervisor Identification Leaf */
74 __cpuid(CpuInfo, 0x40000001);
75
76 /* Is this Hyper-V? */
77 if (CpuInfo[0] == '1#vH')
78 {
79 /* Get the Hypervisor Feature Identification Leaf */
80 __cpuid(CpuInfo, 0x40000003);
81
82 /* Check if HV_X64_MSR_REFERENCE_TSC is present */
83 if (CpuInfo[3] & 0x100)
84 {
85 /* Read the TSC frequency from the MSR */
87 return STATUS_SUCCESS;
88 }
89 }
90 }
91
92 /* On other systems, compute it */
94#else
95 EfiPrintf(L"BlpTimeCalibratePerformanceCounter not implemented for this platform.\r\n");
97#endif
98}
VOID EfiPrintf(_In_ PWCHAR Format,...)
Definition: firmware.c:126
ULONGLONG BlpTimePerformanceFrequency
Definition: time.c:15
NTSTATUS BlpTimeMeasureTscFrequency(VOID)
Definition: time.c:20
PPC_QUAL void __cpuid(int CPUInfo[], const int InfoType)
Definition: intrin_ppc.h:682
PPC_QUAL unsigned long long __readmsr()
Definition: intrin_ppc.h:741
#define STATUS_NOT_IMPLEMENTED
Definition: ntstatus.h:239
#define L(x)
Definition: ntvdm.h:50
#define STATUS_SUCCESS
Definition: shellext.h:65
int32_t INT
Definition: typedefs.h:58

Referenced by InitializeLibrary().

◆ BlpTimeMeasureTscFrequency()

NTSTATUS BlpTimeMeasureTscFrequency ( VOID  )

Definition at line 20 of file time.c.

23{
24#if defined(_M_IX86) || defined(_M_X64)
26 INT CpuInfo[4];
27 ULONGLONG TimeStamp1, TimeStamp2, Delta;
28
29 /* Check if the ISVM bit it set, meaning we're in a hypervisor */
30 __cpuid(CpuInfo, 1);
31 Count = CpuInfo[2] & 0x80000000 ? 10 : 1;
32
33 /* Loop trying to get an accurate TSC */
34 do
35 {
36 /* Stall for 1us and get count 1 */
37 EfiStall(1);
38 TimeStamp1 = __rdtsc();
39
40 /* Stall for 1000us and get count 2*/
41 EfiStall(1000);
42 TimeStamp2 = __rdtsc();
43
44 /* Stall for 9000us and get the difference */
45 EfiStall(9000);
46 Delta = __rdtsc() - TimeStamp2;
47
48 /* Keep going as long as the TSC is fluctuating */
49 --Count;
50 } while (((TimeStamp2 - TimeStamp1) > Delta) && (Count));
51
52 /* Set the frequency based on the two measurements we took */
53 BlpTimePerformanceFrequency = 125 * (Delta - (TimeStamp2 - TimeStamp1)) & 0x1FFFFFFFFFFFFFF;
54 return STATUS_SUCCESS;
55#else
56 EfiPrintf(L"BlpTimeMeasureTscFrequency not implemented for this platform.\r\n");
58#endif
59}
NTSTATUS EfiStall(_In_ ULONG StallTime)
Definition: firmware.c:1003
PPC_QUAL unsigned long long __rdtsc(void)
Definition: intrin_ppc.h:688
int Count
Definition: noreturn.cpp:7
uint32_t ULONG
Definition: typedefs.h:59
uint64_t ULONGLONG
Definition: typedefs.h:67
static ULONG Delta
Definition: xboxvideo.c:33

Referenced by BlpTimeCalibratePerformanceCounter().

◆ BlTimeQueryPerformanceCounter()

ULONGLONG BlTimeQueryPerformanceCounter ( _Out_opt_ PLARGE_INTEGER  Frequency)

Definition at line 101 of file time.c.

104{
105#if defined(_M_IX86) || defined(_M_X64)
106 /* Check if caller wants frequency */
107 if (Frequency)
108 {
109 /* Return it */
111 }
112
113 /* Return the TSC value */
114 return __rdtsc();
115#else
116 EfiPrintf(L"BlTimeQueryPerformanceCounter not implemented for this platform.\r\n");
117 return 0;
118#endif
119};
static LARGE_INTEGER Frequency
Definition: clock.c:41
LONGLONG QuadPart
Definition: typedefs.h:114

Referenced by BlImgLoadBootApplication().

Variable Documentation

◆ BlpTimePerformanceFrequency