EmulatorPkg/Library/DxeCoreTimerLib/DxeCoreTimerLib.c

   1 /** @file
   2   A non-functional instance of the Timer Library.
   3
   4   Copyright (c) 2007 - 2010, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <PiPei.h>
  16 #include <Library/TimerLib.h>
  17 #include <Library/DebugLib.h>
  18 #include <Library/EmuThunkLib.h>
  19 #include <Library/UefiBootServicesTableLib.h>
  20 #include <Library/UefiLib.h>
  21
  22 #include <Protocol/Timer.h>
  23
  24
  25
  26 /**
  27   Stalls the CPU for at least the given number of microseconds.
  28
  29   Stalls the CPU for the number of microseconds specified by MicroSeconds.
  30
  31   @param  MicroSeconds  The minimum number of microseconds to delay.
  32
  33   @return The value of MicroSeconds inputted.
  34
  35 **/
  36 UINTN
  37 EFIAPI
  38 MicroSecondDelay (
  39   IN      UINTN                     MicroSeconds
  40   )
  41 {
  42   return NanoSecondDelay (MicroSeconds * 1000);
  43 }
  44
  45
  46 /**
  47   Stalls the CPU for at least the given number of nanoseconds.
  48
  49   Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
  50
  51   @param  NanoSeconds The minimum number of nanoseconds to delay.
  52
  53   @return The value of NanoSeconds inputted.
  54
  55 **/
  56 UINTN
  57 EFIAPI
  58 NanoSecondDelay (
  59   IN      UINTN                     NanoSeconds
  60   )
  61 {
  62   gEmuThunk->Sleep (NanoSeconds);
  63   return NanoSeconds;
  64 }
  65
  66
  67 /**
  68   Retrieves the current value of a 64-bit free running performance counter.
  69
  70   The counter can either count up by 1 or count down by 1. If the physical
  71   performance counter counts by a larger increment, then the counter values
  72   must be translated. The properties of the counter can be retrieved from
  73   GetPerformanceCounterProperties().
  74
  75   @return The current value of the free running performance counter.
  76
  77 **/
  78 UINT64
  79 EFIAPI
  80 GetPerformanceCounter (
  81   VOID
  82   )
  83 {
  84   return gEmuThunk->QueryPerformanceCounter ();
  85 }
  86
  87 /**
  88   Retrieves the 64-bit frequency in Hz and the range of performance counter
  89   values.
  90
  91   If StartValue is not NULL, then the value that the performance counter starts
  92   with immediately after is it rolls over is returned in StartValue. If
  93   EndValue is not NULL, then the value that the performance counter end with
  94   immediately before it rolls over is returned in EndValue. The 64-bit
  95   frequency of the performance counter in Hz is always returned. If StartValue
  96   is less than EndValue, then the performance counter counts up. If StartValue
  97   is greater than EndValue, then the performance counter counts down. For
  98   example, a 64-bit free running counter that counts up would have a StartValue
  99   of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
 100   that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
 101
 102   @param  StartValue  The value the performance counter starts with when it
 103                       rolls over.
 104   @param  EndValue    The value that the performance counter ends with before
 105                       it rolls over.
 106
 107   @return The frequency in Hz.
 108
 109 **/
 110 UINT64
 111 EFIAPI
 112 GetPerformanceCounterProperties (
 113   OUT      UINT64                    *StartValue,  OPTIONAL
 114   OUT      UINT64                    *EndValue     OPTIONAL
 115   )
 116 {
 117
 118   if (StartValue != NULL) {
 119     *StartValue = 0ULL;
 120   }
 121   if (EndValue != NULL) {
 122     *EndValue = (UINT64)-1LL;
 123   }
 124
 125   return gEmuThunk->QueryPerformanceFrequency ();
 126 }
 127
 128