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: Make sure that there are only limited number
  39  *        of pending timer IRQ events queued. This makes sure that
  40  *        timer handling does not eat all available memory even
  41  *        if IRQ handling stops for some reason (suspended process?).
  42  *        This is easy to do by using DOSRELAY parameter.
  43  * FIXME: Use timeSetEvent, NtSetEvent or timer thread for more precise
  44  *        timing.
  45  * FIXME: Move Win16 timer emulation code here.
  46  */
  47
  48 /* The PC clocks ticks at 1193180 Hz. */
  49 #define TIMER_FREQ 1193180
  50
  51 /* Unique system timer identifier. */
  52 static UINT_PTR TIMER_id = 0;
  53
  54 /* Time when timer IRQ was last queued. */
  55 static DWORD TIMER_stamp = 0;
  56
  57 /* Timer ticks between timer IRQs. */
  58 static UINT TIMER_ticks = 0;
  59
  60
  61 /***********************************************************************
  62  *              TIMER_TimerProc
  63  */
  64 static void CALLBACK TIMER_TimerProc( HWND     hwnd,
  65                                       UINT     uMsg,
  66                                       UINT_PTR idEvent,
  67                                       DWORD    dwTime )
  68 {
  69     TIMER_stamp = dwTime;
  70     DOSVM_QueueEvent( 0, DOS_PRIORITY_REALTIME, NULL, NULL );
  71 }
  72
  73
  74 /***********************************************************************
  75  *              TIMER_DoSetTimer
  76  */
  77 static void WINAPI TIMER_DoSetTimer( ULONG_PTR arg )
  78 {
  79     INT millis = MulDiv( arg, 1000, TIMER_FREQ );
  80
  81     /* sanity check - too fast timer */
  82     if (millis < 1)
  83         millis = 1;
  84
  85     TRACE_(int)( "setting timer tick delay to %d ms\n", millis );
  86
  87     if (TIMER_id)
  88         KillTimer( NULL, TIMER_id );
  89
  90     TIMER_id = SetTimer( NULL, 0, millis, TIMER_TimerProc );
  91     TIMER_stamp = GetTickCount();
  92     TIMER_ticks = arg;
  93 }
  94
  95
  96 /***********************************************************************
  97  *              DOSVM_GetTimer
  98  */
  99 UINT WINAPI DOSVM_GetTimer( void )
 100 {
 101     if (!DOSVM_IsWin16())
 102     {
 103         DWORD millis = GetTickCount() - TIMER_stamp;
 104         INT   ticks = MulDiv( millis, TIMER_FREQ, 1000 );
 105
 106         /* sanity check - tick wrap or suspended process or update race */
 107         if (ticks < 0 || ticks >= TIMER_ticks)
 108             ticks = 0;
 109
 110         return ticks;
 111     }
 112
 113     return 0;
 114 }
 115
 116
 117 /***********************************************************************
 118  *              DOSVM_SetTimer
 119  */
 120 void WINAPI DOSVM_SetTimer( UINT ticks )
 121 {
 122     if (!DOSVM_IsWin16())
 123         MZ_RunInThread( TIMER_DoSetTimer, ticks );
 124 }
 125
 126
 127 /***********************************************************************
 128  *              DOSVM_Int08Handler
 129  *
 130  * DOS interrupt 08h handler (IRQ0 - TIMER).
 131  */
 132 void WINAPI DOSVM_Int08Handler( CONTEXT86 *context )
 133 {
 134     BIOSDATA *bios_data      = DOSVM_BiosData();
 135     CONTEXT86 nested_context = *context;
 136     FARPROC16 int1c_proc     = DOSVM_GetRMHandler( 0x1c );
 137
 138     nested_context.SegCs = SELECTOROF(int1c_proc);
 139     nested_context.Eip   = OFFSETOF(int1c_proc);
 140
 141     /*
 142      * Update BIOS ticks since midnight.
 143      *
 144      * FIXME: What to do when number of ticks exceeds ticks per day?
 145      */
 146     bios_data->Ticks++;
 147
 148     /*
 149      * If IRQ is called from protected mode, convert
 150      * context into VM86 context. Stack is invalidated so
 151      * that DPMI_CallRMProc allocates a new stack.
 152      */
 153     if (!ISV86(&nested_context))
 154     {
 155         nested_context.EFlags |= V86_FLAG;
 156         nested_context.SegSs = 0;
 157     }
 158
 159     /*
 160      * Call interrupt 0x1c.
 161      */
 162     DPMI_CallRMProc( &nested_context, NULL, 0, TRUE );
 163
 164     DOSVM_AcknowledgeIRQ( context );
 165 }