166 lines
4.7 KiB
C
166 lines
4.7 KiB
C
/*
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* 8253/8254 Programmable Interval Timer (PIT) emulation
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*
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* Copyright 2003 Jukka Heinonen
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "config.h"
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#include "dosexe.h"
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#include "wine/debug.h"
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#include "wingdi.h"
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#include "winuser.h"
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WINE_DEFAULT_DEBUG_CHANNEL(int);
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/*
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* FIXME: Use QueryPerformanceCounter for
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* more precise GetTimer implementation.
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* FIXME: Use QueryPerformanceCounter (or GetTimer implementation)
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* in timer tick routine to compensate for lost ticks.
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* This should also make it possible to
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* emulate really fast timers.
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* FIXME: Support special timer modes in addition to periodic mode.
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* FIXME: Make sure that there are only limited number
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* of pending timer IRQ events queued. This makes sure that
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* timer handling does not eat all available memory even
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* if IRQ handling stops for some reason (suspended process?).
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* This is easy to do by using DOSRELAY parameter.
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* FIXME: Use timeSetEvent, NtSetEvent or timer thread for more precise
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* timing.
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* FIXME: Move Win16 timer emulation code here.
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*/
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/* The PC clocks ticks at 1193180 Hz. */
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#define TIMER_FREQ 1193180
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/* Unique system timer identifier. */
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static UINT_PTR TIMER_id = 0;
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/* Time when timer IRQ was last queued. */
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static DWORD TIMER_stamp = 0;
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/* Timer ticks between timer IRQs. */
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static UINT TIMER_ticks = 0;
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/***********************************************************************
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* TIMER_TimerProc
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*/
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static void CALLBACK TIMER_TimerProc( HWND hwnd,
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UINT uMsg,
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UINT_PTR idEvent,
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DWORD dwTime )
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{
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TIMER_stamp = dwTime;
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DOSVM_QueueEvent( 0, DOS_PRIORITY_REALTIME, NULL, NULL );
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}
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/***********************************************************************
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* TIMER_DoSetTimer
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*/
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static void WINAPI TIMER_DoSetTimer( ULONG_PTR arg )
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{
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INT millis = MulDiv( arg, 1000, TIMER_FREQ );
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/* sanity check - too fast timer */
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if (millis < 1)
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millis = 1;
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TRACE_(int)( "setting timer tick delay to %d ms\n", millis );
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if (TIMER_id)
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KillTimer( NULL, TIMER_id );
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TIMER_id = SetTimer( NULL, 0, millis, TIMER_TimerProc );
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TIMER_stamp = GetTickCount();
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TIMER_ticks = arg;
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}
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/***********************************************************************
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* DOSVM_GetTimer
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*/
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UINT WINAPI DOSVM_GetTimer( void )
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{
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if (!DOSVM_IsWin16())
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{
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DWORD millis = GetTickCount() - TIMER_stamp;
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INT ticks = MulDiv( millis, TIMER_FREQ, 1000 );
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/* sanity check - tick wrap or suspended process or update race */
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if (ticks < 0 || ticks >= TIMER_ticks)
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ticks = 0;
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return ticks;
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}
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return 0;
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}
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/***********************************************************************
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* DOSVM_SetTimer
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*/
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void WINAPI DOSVM_SetTimer( UINT ticks )
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{
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if (!DOSVM_IsWin16())
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MZ_RunInThread( TIMER_DoSetTimer, ticks );
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}
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/***********************************************************************
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* DOSVM_Int08Handler
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*
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* DOS interrupt 08h handler (IRQ0 - TIMER).
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*/
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void WINAPI DOSVM_Int08Handler( CONTEXT86 *context )
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{
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BIOSDATA *bios_data = DOSVM_BiosData();
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CONTEXT86 nested_context = *context;
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FARPROC16 int1c_proc = DOSVM_GetRMHandler( 0x1c );
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nested_context.SegCs = SELECTOROF(int1c_proc);
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nested_context.Eip = OFFSETOF(int1c_proc);
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/*
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* Update BIOS ticks since midnight.
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*
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* FIXME: What to do when number of ticks exceeds ticks per day?
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*/
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bios_data->Ticks++;
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/*
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* If IRQ is called from protected mode, convert
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* context into VM86 context. Stack is invalidated so
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* that DPMI_CallRMProc allocates a new stack.
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*/
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if (!ISV86(&nested_context))
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{
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nested_context.EFlags |= V86_FLAG;
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nested_context.SegSs = 0;
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}
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/*
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* Call interrupt 0x1c.
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*/
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DPMI_CallRMProc( &nested_context, NULL, 0, TRUE );
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DOSVM_AcknowledgeIRQ( context );
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}
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