dlls/winedos/timer.c

   1 /*
   2  * 8253/8254 Programmable Interval Timer (PIT) emulation
   3  *
   4  * Copyright 2003 Jukka Heinonen
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22
  23 #include "dosexe.h"
  24 #include "wine/debug.h"
  25 #include "wingdi.h"
  26 #include "winuser.h"
  27
  28 WINE_DEFAULT_DEBUG_CHANNEL(int);
  29
  30 /*
  31  * FIXME: Use QueryPerformanceCounter for
  32  *        more precise GetTimer implementation.
  33  * FIXME: Use QueryPerformanceCounter (or GetTimer implementation)
  34  *        in timer tick routine to compensate for lost ticks.
  35  *        This should also make it possible to
  36  *        emulate really fast timers.
  37  * FIXME: Support special timer modes in addition to periodic mode.
  38  * FIXME: Use timeSetEvent, NtSetEvent or timer thread for more precise
  39  *        timing.
  40  * FIXME: Move Win16 timer emulation code here.
  41  */
  42
  43 /* The PC clocks ticks at 1193180 Hz. */
  44 #define TIMER_FREQ 1193180
  45
  46 /* How many timer IRQs can be pending at any time. */
  47 #define TIMER_MAX_PENDING 20
  48
  49 /* Unique system timer identifier. */
  50 static UINT_PTR TIMER_id = 0;
  51
  52 /* Time when timer IRQ was last queued. */
  53 static DWORD TIMER_stamp = 0;
  54
  55 /* Timer ticks between timer IRQs. */
  56 static UINT TIMER_ticks = 0;
  57
  58 /* Number of pending timer IRQs. */
  59 static LONG TIMER_pending = 0;
  60
  61
  62 /***********************************************************************
  63  *              TIMER_Relay
  64  *
  65  * Decrement the number of pending IRQs after IRQ handler has been
  66  * called. This function will be called even if application has its
  67  * own IRQ handler that does not jump to builtin IRQ handler.
  68  */
  69 static void TIMER_Relay( CONTEXT86 *context, void *data )
  70 {
  71     InterlockedDecrement( &TIMER_pending );
  72 }
  73
  74
  75 /***********************************************************************
  76  *              TIMER_TimerProc
  77  */
  78 static void CALLBACK TIMER_TimerProc( HWND     hwnd,
  79                                       UINT     uMsg,
  80                                       UINT_PTR idEvent,
  81                                       DWORD    dwTime )
  82 {
  83     LONG pending = InterlockedIncrement( &TIMER_pending );
  84
  85     if (pending >= TIMER_MAX_PENDING)
  86     {
  87         DWORD delta = (dwTime >= TIMER_stamp) ?
  88             (dwTime - TIMER_stamp) : (0xffffffff - (TIMER_stamp - dwTime));
  89
  90         if (delta >= 60000)
  91         {
  92             ERR( "DOS timer has been stuck for 60 seconds...\n" );
  93             TIMER_stamp = dwTime;
  94         }
  95
  96         InterlockedDecrement( &TIMER_pending );
  97     }
  98     else
  99     {
 100         TIMER_stamp = dwTime;
 101         DOSVM_QueueEvent( 0, DOS_PRIORITY_REALTIME, TIMER_Relay, NULL );
 102     }
 103 }
 104
 105
 106 /***********************************************************************
 107  *              TIMER_DoSetTimer
 108  */
 109 static void WINAPI TIMER_DoSetTimer( ULONG_PTR arg )
 110 {
 111     INT millis = MulDiv( arg, 1000, TIMER_FREQ );
 112
 113     /* sanity check - too fast timer */
 114     if (millis < 1)
 115         millis = 1;
 116
 117     TRACE_(int)( "setting timer tick delay to %d ms\n", millis );
 118
 119     if (TIMER_id)
 120         KillTimer( NULL, TIMER_id );
 121
 122     TIMER_id = SetTimer( NULL, 0, millis, TIMER_TimerProc );
 123     TIMER_stamp = GetTickCount();
 124     TIMER_ticks = arg;
 125 }
 126
 127
 128 /***********************************************************************
 129  *              DOSVM_GetTimer
 130  */
 131 UINT WINAPI DOSVM_GetTimer( void )
 132 {
 133     if (!DOSVM_IsWin16())
 134     {
 135         DWORD millis = GetTickCount() - TIMER_stamp;
 136         INT   ticks = MulDiv( millis, TIMER_FREQ, 1000 );
 137
 138         /* sanity check - tick wrap or suspended process or update race */
 139         if (ticks < 0 || ticks >= TIMER_ticks)
 140             ticks = 0;
 141
 142         return ticks;
 143     }
 144
 145     return 0;
 146 }
 147
 148
 149 /***********************************************************************
 150  *              DOSVM_SetTimer
 151  */
 152 void WINAPI DOSVM_SetTimer( UINT ticks )
 153 {
 154     /* PIT interprets zero as a maximum length delay. */
 155     if (ticks == 0)
 156         ticks = 0x10000;
 157
 158     if (!DOSVM_IsWin16())
 159         MZ_RunInThread( TIMER_DoSetTimer, ticks );
 160 }
 161
 162
 163 /***********************************************************************
 164  *              DOSVM_Int08Handler
 165  *
 166  * DOS interrupt 08h handler (IRQ0 - TIMER).
 167  */
 168 void WINAPI DOSVM_Int08Handler( CONTEXT86 *context )
 169 {
 170     BIOSDATA *bios_data      = DOSVM_BiosData();
 171     CONTEXT86 nested_context = *context;
 172     FARPROC16 int1c_proc     = DOSVM_GetRMHandler( 0x1c );
 173
 174     nested_context.SegCs = SELECTOROF(int1c_proc);
 175     nested_context.Eip   = OFFSETOF(int1c_proc);
 176
 177     /*
 178      * Update BIOS ticks since midnight.
 179      *
 180      * FIXME: What to do when number of ticks exceeds ticks per day?
 181      */
 182     bios_data->Ticks++;
 183
 184     /*
 185      * If IRQ is called from protected mode, convert
 186      * context into VM86 context. Stack is invalidated so
 187      * that DPMI_CallRMProc allocates a new stack.
 188      */
 189     if (!ISV86(&nested_context))
 190     {
 191         nested_context.EFlags |= V86_FLAG;
 192         nested_context.SegSs = 0;
 193     }
 194
 195     /*
 196      * Call interrupt 0x1c.
 197      */
 198     DPMI_CallRMProc( &nested_context, NULL, 0, TRUE );
 199
 200     DOSVM_AcknowledgeIRQ( context );
 201 }