dlls/krnl386.exe16/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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, 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 /* Number of milliseconds between IRQs. */
  62 static DWORD TIMER_millis = 0;
  63
  64 /***********************************************************************
  65  *              TIMER_Relay
  66  *
  67  * Decrement the number of pending IRQs after IRQ handler has been
  68  * called. This function will be called even if application has its
  69  * own IRQ handler that does not jump to builtin IRQ handler.
  70  */
  71 static void TIMER_Relay( CONTEXT86 *context, void *data )
  72 {
  73     InterlockedDecrement( &TIMER_pending );
  74 }
  75
  76
  77 /***********************************************************************
  78  *              TIMER_TimerProc
  79  */
  80 static void CALLBACK TIMER_TimerProc( HWND     hwnd,
  81                                       UINT     uMsg,
  82                                       UINT_PTR idEvent,
  83                                       DWORD    dwTime )
  84 {
  85     LONG pending = InterlockedIncrement( &TIMER_pending );
  86     DWORD delta = (dwTime >= TIMER_stamp) ?
  87         (dwTime - TIMER_stamp) : (0xffffffff - (TIMER_stamp - dwTime));
  88
  89     if (pending >= TIMER_MAX_PENDING)
  90     {
  91
  92         if (delta >= 60000)
  93         {
  94             ERR( "DOS timer has been stuck for 60 seconds...\n" );
  95             TIMER_stamp = dwTime;
  96         }
  97
  98         InterlockedDecrement( &TIMER_pending );
  99     }
 100     else
 101     {
 102         DWORD i;
 103
 104         /* Calculate the number of valid timer interrupts we can generate */
 105         DWORD count = delta / TIMER_millis;
 106
 107         /* Forward the timestamp with the time used */
 108         TIMER_stamp += (count * TIMER_millis);
 109
 110         /* Generate interrupts */
 111         for(i=0;i<count;i++)
 112         {
 113           DOSVM_QueueEvent( 0, DOS_PRIORITY_REALTIME, TIMER_Relay, NULL );
 114         }
 115     }
 116 }
 117
 118
 119 /***********************************************************************
 120  *              TIMER_DoSetTimer
 121  */
 122 static void WINAPI TIMER_DoSetTimer( ULONG_PTR arg )
 123 {
 124     INT millis = MulDiv( arg, 1000, TIMER_FREQ );
 125
 126     /* sanity check - too fast timer */
 127     if (millis < 1)
 128         millis = 1;
 129
 130     TRACE_(int)( "setting timer tick delay to %d ms\n", millis );
 131
 132     if (TIMER_id)
 133         KillTimer( NULL, TIMER_id );
 134
 135     TIMER_id = SetTimer( NULL, 0, millis, TIMER_TimerProc );
 136     TIMER_stamp = GetTickCount();
 137     TIMER_ticks = arg;
 138
 139     /* Remember number of milliseconds to wait */
 140     TIMER_millis = millis;
 141 }
 142
 143
 144 /***********************************************************************
 145  *              DOSVM_SetTimer
 146  */
 147 void DOSVM_SetTimer( UINT ticks )
 148 {
 149     /* PIT interprets zero as a maximum length delay. */
 150     if (ticks == 0)
 151         ticks = 0x10000;
 152
 153     if (!DOSVM_IsWin16())
 154         MZ_RunInThread( TIMER_DoSetTimer, ticks );
 155 }
 156
 157
 158 /***********************************************************************
 159  *              DOSVM_Int08Handler
 160  *
 161  * DOS interrupt 08h handler (IRQ0 - TIMER).
 162  */
 163 void WINAPI DOSVM_Int08Handler( CONTEXT86 *context )
 164 {
 165     BIOSDATA *bios_data      = DOSVM_BiosData();
 166     CONTEXT86 nested_context = *context;
 167     FARPROC16 int1c_proc     = DOSVM_GetRMHandler( 0x1c );
 168
 169     nested_context.SegCs = SELECTOROF(int1c_proc);
 170     nested_context.Eip   = OFFSETOF(int1c_proc);
 171
 172     /*
 173      * Update BIOS ticks since midnight.
 174      *
 175      * FIXME: What to do when number of ticks exceeds ticks per day?
 176      */
 177     bios_data->Ticks++;
 178
 179     /*
 180      * If IRQ is called from protected mode, convert
 181      * context into VM86 context. Stack is invalidated so
 182      * that DPMI_CallRMProc allocates a new stack.
 183      */
 184     if (!ISV86(&nested_context))
 185     {
 186         nested_context.EFlags |= V86_FLAG;
 187         nested_context.SegSs = 0;
 188     }
 189
 190     /*
 191      * Call interrupt 0x1c.
 192      */
 193     DPMI_CallRMProc( &nested_context, NULL, 0, TRUE );
 194
 195     DOSVM_AcknowledgeIRQ( context );
 196 }