1 /** @file 2 Provides calibrated delay and performance counter services. 3 4 Copyright (c) 2006 - 2011, 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 #ifndef __TIMER_LIB__ 16 #define __TIMER_LIB__ 17 18 /** 19 Stalls the CPU for at least the given number of microseconds. 20 21 Stalls the CPU for the number of microseconds specified by MicroSeconds. 22 23 @param MicroSeconds The minimum number of microseconds to delay. 24 25 @return The value of MicroSeconds inputted. 26 27 **/ 28 UINTN 29 EFIAPI 30 MicroSecondDelay ( 31 IN UINTN MicroSeconds 32 ); 33 34 /** 35 Stalls the CPU for at least the given number of nanoseconds. 36 37 Stalls the CPU for the number of nanoseconds specified by NanoSeconds. 38 39 @param NanoSeconds The minimum number of nanoseconds to delay. 40 41 @return The value of NanoSeconds inputted. 42 43 **/ 44 UINTN 45 EFIAPI 46 NanoSecondDelay ( 47 IN UINTN NanoSeconds 48 ); 49 50 /** 51 Retrieves the current value of a 64-bit free running performance counter. 52 53 The counter can either count up by 1 or count down by 1. If the physical 54 performance counter counts by a larger increment, then the counter values 55 must be translated. The properties of the counter can be retrieved from 56 GetPerformanceCounterProperties(). 57 58 @return The current value of the free running performance counter. 59 60 **/ 61 UINT64 62 EFIAPI 63 GetPerformanceCounter ( 64 VOID 65 ); 66 67 /** 68 Retrieves the 64-bit frequency in Hz and the range of performance counter 69 values. 70 71 If StartValue is not NULL, then the value that the performance counter starts 72 with immediately after is it rolls over is returned in StartValue. If 73 EndValue is not NULL, then the value that the performance counter end with 74 immediately before it rolls over is returned in EndValue. The 64-bit 75 frequency of the performance counter in Hz is always returned. If StartValue 76 is less than EndValue, then the performance counter counts up. If StartValue 77 is greater than EndValue, then the performance counter counts down. For 78 example, a 64-bit free running counter that counts up would have a StartValue 79 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter 80 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0. 81 82 @param StartValue The value the performance counter starts with when it 83 rolls over. 84 @param EndValue The value that the performance counter ends with before 85 it rolls over. 86 87 @return The frequency in Hz. 88 89 **/ 90 UINT64 91 EFIAPI 92 GetPerformanceCounterProperties ( 93 OUT UINT64 *StartValue, OPTIONAL 94 OUT UINT64 *EndValue OPTIONAL 95 ); 96 97 /** 98 Converts elapsed ticks of performance counter to time in nanoseconds. 99 100 This function converts the elapsed ticks of running performance counter to 101 time value in unit of nanoseconds. 102 103 @param Ticks The number of elapsed ticks of running performance counter. 104 105 @return The elapsed time in nanoseconds. 106 107 **/ 108 UINT64 109 EFIAPI 110 GetTimeInNanoSecond ( 111 IN UINT64 Ticks 112 ); 113 114 #endif 115