reactos/hal/halx86/generic/timer.c

   1 /*
   2  * PROJECT:         ReactOS HAL
   3  * LICENSE:         GPL - See COPYING in the top level directory
   4  * FILE:            hal/halx86/generic/timer.c
   5  * PURPOSE:         HAL Timer Routines
   6  * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
   7  */
   8
   9 /* INCLUDES ******************************************************************/
  10
  11 #include <hal.h>
  12 #define NDEBUG
  13 #include <debug.h>
  14
  15 /* GLOBALS *******************************************************************/
  16
  17 BOOLEAN HalpClockSetMSRate;
  18 ULONG HalpCurrentTimeIncrement;
  19 ULONG HalpCurrentRollOver;
  20 ULONG HalpNextMSRate = 14;
  21 ULONG HalpLargestClockMS = 15;
  22
  23 LARGE_INTEGER HalpRolloverTable[15] =
  24 {
  25     {{1197, 10032}},
  26     {{2394, 20064}},
  27     {{3591, 30096}},
  28     {{4767, 39952}},
  29     {{5964, 49984}},
  30     {{7161, 60016}},
  31     {{8358, 70048}},
  32     {{9555, 80080}},
  33     {{10731, 89936}},
  34     {{11949, 100144}},
  35     {{13125, 110000}},
  36     {{14322, 120032}},
  37     {{15519, 130064}},
  38     {{16695, 139920}},
  39     {{17892, 149952}}
  40 };
  41
  42 /* PRIVATE FUNCTIONS *********************************************************/
  43
  44 VOID
  45 NTAPI
  46 HalpInitializeClock(VOID)
  47 {
  48     PKPRCB Prcb = KeGetCurrentPrcb();
  49     ULONG Increment;
  50     USHORT RollOver;
  51     ULONG_PTR Flags = 0;
  52
  53     /* Check the CPU Type */
  54     if (Prcb->CpuType <= 4)
  55     {
  56         /* 486's or equal can't go higher then 10ms */
  57         HalpLargestClockMS = 10;
  58         HalpNextMSRate = 9;
  59     }
  60
  61     /* Get increment and rollover for the largest time clock ms possible */
  62     Increment= HalpRolloverTable[HalpLargestClockMS - 1].HighPart;
  63     RollOver = (USHORT)HalpRolloverTable[HalpLargestClockMS - 1].LowPart;
  64
  65     /* Set the maximum and minimum increment with the kernel */
  66     HalpCurrentTimeIncrement = Increment;
  67     KeSetTimeIncrement(Increment, HalpRolloverTable[0].HighPart);
  68
  69     /* Disable interrupts */
  70     Ke386SaveFlags(Flags);
  71     _disable();
  72
  73     /* Set the rollover */
  74     __outbyte(TIMER_CONTROL_PORT, TIMER_SC0 | TIMER_BOTH | TIMER_MD2);
  75     __outbyte(TIMER_DATA_PORT0, RollOver & 0xFF);
  76     __outbyte(TIMER_DATA_PORT0, RollOver >> 8);
  77
  78     /* Restore interrupts if they were previously enabled */
  79     Ke386RestoreFlags(Flags);
  80
  81     /* Save rollover and return */
  82     HalpCurrentRollOver = RollOver;
  83 }
  84
  85 /* PUBLIC FUNCTIONS ***********************************************************/
  86
  87 /*
  88  * @implemented
  89  */
  90 VOID
  91 NTAPI
  92 HalCalibratePerformanceCounter(IN volatile PLONG Count,
  93                                IN ULONGLONG NewCount)
  94 {
  95     ULONG_PTR Flags = 0;
  96
  97     /* Disable interrupts */
  98     Ke386SaveFlags(Flags);
  99     _disable();
 100
 101     /* Do a decrement for this CPU */
 102     _InterlockedDecrement(Count);
 103
 104     /* Wait for other CPUs */
 105     while (*Count);
 106
 107     /* Restore interrupts if they were previously enabled */
 108     Ke386RestoreFlags(Flags);
 109 }
 110
 111 /*
 112  * @implemented
 113  */
 114 ULONG
 115 NTAPI
 116 HalSetTimeIncrement(IN ULONG Increment)
 117 {
 118     /* Round increment to ms */
 119     Increment /= 10000;
 120
 121     /* Normalize between our minimum (1 ms) and maximum (variable) setting */
 122     if (Increment > HalpLargestClockMS) Increment = HalpLargestClockMS;
 123     if (Increment <= 0) Increment = 1;
 124
 125     /* Set the rate and tell HAL we want to change it */
 126     HalpNextMSRate = Increment;
 127     HalpClockSetMSRate = TRUE;
 128
 129     /* Return the increment */
 130     return HalpRolloverTable[Increment - 1].HighPart;
 131 }
 132
 133 /* EOF */