554 lines
17 KiB
C++
554 lines
17 KiB
C++
////////////////////////////////////////////////////////////////////////
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// $Id: virt_timer.cc,v 1.22 2005-06-04 17:44:58 vruppert Exp $
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/////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2002 MandrakeSoft S.A.
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//
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// MandrakeSoft S.A.
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// 43, rue d'Aboukir
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// 75002 Paris - France
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// http://www.linux-mandrake.com/
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// http://www.mandrakesoft.com/
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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 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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//
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//Realtime Algorithm (with gettimeofday)
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// HAVE:
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// Real number of usec.
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// Emulated number of usec.
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// WANT:
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// Number of ticks to use.
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// Number of emulated usec to wait until next try.
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//
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// ticks=number of ticks needed to match total real usec.
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// if(desired ticks > max ticks for elapsed real time)
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// ticks = max ticks for elapsed real time.
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// if(desired ticks > max ticks for elapsed emulated usec)
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// ticks = max ticks for emulated usec.
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// next wait ticks = number of ticks until next event.
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// next wait real usec = (current ticks + next wait ticks) * usec per ticks
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// next wait emulated usec = next wait real usec * emulated usec / real usec
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// if(next wait emulated usec < minimum emulated usec for next wait ticks)
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// next wait emulated usec = minimum emulated usec for next wait ticks.
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// if(next wait emulated usec > max emulated usec wait)
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// next wait emulated usec = max emulated usec wait.
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//
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// How to calculate elapsed real time:
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// store an unused time value whenever no ticks are used in a given time.
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// add this to the current elapsed time.
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// How to calculate elapsed emulated time:
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// same as above.
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// Above can be done by not updating last_usec and last_sec.
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//
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// How to calculate emulated usec/real usec:
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// Each time there are actual ticks:
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// Alpha_product(old emulated usec, emulated usec);
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// Alpha_product(old real usec, real usec);
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// Divide resulting values.
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//
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/////////////////////////////////////////////////////////////////////////
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#include "iodev.h"
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#define BX_USE_VIRTUAL_TIMERS 1
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#define BX_VIRTUAL_TIMERS_REALTIME 1
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//Important constant #defines:
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#define USEC_PER_SECOND (1000000)
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// define a macro to convert floating point numbers into 64-bit integers.
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// In MSVC++ you can convert a 64-bit float into a 64-bit signed integer,
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// but it will not convert a 64-bit float into a 64-bit unsigned integer.
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// This macro works around that.
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#define F2I(x) ((Bit64u)(Bit64s) (x))
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#define I2F(x) ((double)(Bit64s) (x))
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//CONFIGURATION #defines:
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//MAINLINE Configuration (For realtime PIT):
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//How much faster than real time we can go:
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#define MAX_MULT (1.25)
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//Minimum number of emulated useconds per second.
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// Now calculated using BX_MIN_IPS, the minimum number of
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// instructions per second.
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#define MIN_USEC_PER_SECOND (((((Bit64u)USEC_PER_SECOND)*((Bit64u)BX_MIN_IPS))/((Bit64u)(bx_options.Oips->get())))+(Bit64u)1)
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//DEBUG configuration:
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//Debug with printf options.
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#define DEBUG_REALTIME_WITH_PRINTF 0
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//Use to test execution at multiples of real time.
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#define TIME_DIVIDER (1)
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#define TIME_MULTIPLIER (1)
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#define TIME_HEADSTART (0)
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#define GET_VIRT_REALTIME64_USEC() (((bx_get_realtime64_usec()*(Bit64u)TIME_MULTIPLIER/(Bit64u)TIME_DIVIDER)))
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//Set up Logging.
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#define LOG_THIS bx_virt_timer.
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//A single instance.
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bx_virt_timer_c bx_virt_timer;
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//Generic MAX and MIN Functions
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#define BX_MAX(a,b) ( ((a)>(b))?(a):(b) )
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#define BX_MIN(a,b) ( ((a)>(b))?(b):(a) )
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//USEC_ALPHA is multiplier for the past.
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//USEC_ALPHA_B is 1-USEC_ALPHA, or multiplier for the present.
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#define USEC_ALPHA ((double)(.8))
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#define USEC_ALPHA_B ((double)(((double)1)-USEC_ALPHA))
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#define USEC_ALPHA2 ((double)(.5))
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#define USEC_ALPHA2_B ((double)(((double)1)-USEC_ALPHA2))
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#define ALPHA_LOWER(old,new) ((Bit64u)((old<new)?((USEC_ALPHA*(I2F(old)))+(USEC_ALPHA_B*(I2F(new)))):((USEC_ALPHA2*(I2F(old)))+(USEC_ALPHA2_B*(I2F(new))))))
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//Conversion between emulated useconds and optionally realtime ticks.
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#define TICKS_TO_USEC(a) ( ((a)*usec_per_second)/ticks_per_second )
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#define USEC_TO_TICKS(a) ( ((a)*ticks_per_second)/usec_per_second )
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bx_virt_timer_c::bx_virt_timer_c( void )
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{
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put("VTIMER");
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settype(VTIMERLOG);
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numTimers = 0;
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current_timers_time = 0;
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timers_next_event_time = BX_MAX_VIRTUAL_TIME;
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last_sequential_time = 0;
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in_timer_handler = 0;
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virtual_next_event_time = BX_MAX_VIRTUAL_TIME;
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current_virtual_time = 0;
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use_virtual_timers = BX_USE_VIRTUAL_TIMERS;
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init_done = 0;
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}
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bx_virt_timer_c::~bx_virt_timer_c( void )
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{
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}
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const Bit64u bx_virt_timer_c::NullTimerInterval = BX_MAX_VIRTUAL_TIME;
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void
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bx_virt_timer_c::nullTimer(void* this_ptr) {
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UNUSED(this_ptr);
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}
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void
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bx_virt_timer_c::periodic(Bit64u time_passed) {
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//Assert that we haven't skipped any events.
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BX_ASSERT (time_passed <= timers_next_event_time);
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BX_ASSERT(!in_timer_handler);
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//Update time variables.
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timers_next_event_time -= time_passed;
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current_timers_time += time_passed;
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//If no events are occurring, just pass the time and we're done.
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if( time_passed < timers_next_event_time ) {
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return;
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}
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//Starting timer handler calls.
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in_timer_handler = 1;
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//Otherwise, cause any events to occur that should.
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unsigned i;
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for(i=0;i<numTimers;i++) {
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if( timer[i].inUse && timer[i].active ) {
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//Assert that we haven't skipped any timers.
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BX_ASSERT(current_timers_time <= timer[i].timeToFire);
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if(timer[i].timeToFire == current_timers_time) {
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if(timer[i].continuous) {
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timer[i].timeToFire+=timer[i].period;
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} else {
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timer[i].active = 0;
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}
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//This function MUST return, or the timer mechanism
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// will be broken.
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timer[i].funct(timer[i].this_ptr);
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}
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}
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}
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//Finished timer handler calls.
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in_timer_handler = 0;
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//Use a second FOR loop so that a timer function call can
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// change the behavior of another timer.
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//timers_next_event_time normally contains a cycle count, not a cycle time.
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// here we use it as a temporary variable that IS a cycle time,
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// but then convert it back to a cycle count afterwards.
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timers_next_event_time = current_timers_time + BX_MAX_VIRTUAL_TIME;
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for(i=0;i<numTimers;i++) {
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if( timer[i].inUse && timer[i].active && ((timer[i].timeToFire)<timers_next_event_time) ) {
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timers_next_event_time = timer[i].timeToFire;
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}
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}
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timers_next_event_time-=current_timers_time;
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next_event_time_update();
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//FIXME
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}
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//Get the current virtual time.
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// This may return the same value on subsequent calls.
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Bit64u
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bx_virt_timer_c::time_usec(void) {
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if(!use_virtual_timers) {
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return bx_pc_system.time_usec();
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}
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//Update the time here only if we're not in a timer handler.
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//If we're in a timer handler we're up-to-date, and otherwise
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// this prevents call stack loops.
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if(!in_timer_handler) {
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timer_handler();
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}
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return current_timers_time;
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}
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//Get the current virtual time.
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// This will return a monotonically increasing value.
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// MUST NOT be called from within a timer interrupt.
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Bit64u
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bx_virt_timer_c::time_usec_sequential(void) {
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if(!use_virtual_timers) {
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return bx_pc_system.time_usec_sequential();
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}
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//Can't prevent call stack loops here, so this
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// MUST NOT be called from within a timer handler.
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BX_ASSERT(timers_next_event_time>0);
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BX_ASSERT(!in_timer_handler);
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if(last_sequential_time >= current_timers_time) {
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periodic(1);
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last_sequential_time = current_timers_time;
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}
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return current_timers_time;
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}
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//Register a timer handler to go off after a given interval.
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//Register a timer handler to go off with a periodic interval.
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int
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bx_virt_timer_c::register_timer( void *this_ptr, bx_timer_handler_t handler,
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Bit32u useconds,
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bx_bool continuous, bx_bool active,
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const char *id) {
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if(!use_virtual_timers) {
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return bx_pc_system.register_timer(this_ptr, handler, useconds,
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continuous, active, id);
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}
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//We don't like starting with a zero period timer.
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BX_ASSERT((!active) || (useconds>0));
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//Search for an unused timer.
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unsigned int i;
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for (i=0; i < numTimers; i++) {
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if (timer[i].inUse == 0 || i==numTimers)
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break;
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}
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// If we didn't find a free slot, increment the bound, numTimers.
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if (i==numTimers)
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numTimers++; // One new timer installed.
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BX_ASSERT(numTimers<BX_MAX_VIRTUAL_TIMERS);
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timer[i].inUse = 1;
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timer[i].period = useconds;
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timer[i].timeToFire = current_timers_time + (Bit64u)useconds;
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timer[i].active = active;
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timer[i].continuous = continuous;
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timer[i].funct = handler;
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timer[i].this_ptr = this_ptr;
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strncpy(timer[i].id, id, BxMaxTimerIDLen);
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timer[i].id[BxMaxTimerIDLen-1]=0; //I like null terminated strings.
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if(useconds < timers_next_event_time) {
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timers_next_event_time = useconds;
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next_event_time_update();
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//FIXME
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}
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return i;
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}
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//unregister a previously registered timer.
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unsigned
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bx_virt_timer_c::unregisterTimer(int timerID) {
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if(!use_virtual_timers) {
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return bx_pc_system.unregisterTimer(timerID);
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}
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BX_ASSERT(timerID >= 0);
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BX_ASSERT(timerID < BX_MAX_VIRTUAL_TIMERS);
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if (timer[timerID].active) {
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BX_PANIC(("unregisterTimer: timer '%s' is still active!", timer[timerID].id));
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return(0); // Fail.
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}
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//No need to prevent doing this to unused timers.
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timer[timerID].inUse = 0;
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return(1);
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}
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void
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bx_virt_timer_c::start_timers(void) {
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if(!use_virtual_timers) {
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bx_pc_system.start_timers();
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return;
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}
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//FIXME
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}
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//activate a deactivated but registered timer.
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void
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bx_virt_timer_c::activate_timer( unsigned timer_index, Bit32u useconds,
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bx_bool continuous ) {
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if(!use_virtual_timers) {
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bx_pc_system.activate_timer(timer_index, useconds, continuous);
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return;
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}
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BX_ASSERT(timer_index >= 0);
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BX_ASSERT(timer_index < BX_MAX_VIRTUAL_TIMERS);
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BX_ASSERT(timer[timer_index].inUse);
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BX_ASSERT(useconds>0);
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timer[timer_index].period=useconds;
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timer[timer_index].timeToFire = current_timers_time + (Bit64u)useconds;
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timer[timer_index].active=1;
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timer[timer_index].continuous=continuous;
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if(useconds < timers_next_event_time) {
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timers_next_event_time = useconds;
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next_event_time_update();
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//FIXME
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}
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}
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//deactivate (but don't unregister) a currently registered timer.
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void
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bx_virt_timer_c::deactivate_timer( unsigned timer_index ) {
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if(!use_virtual_timers) {
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bx_pc_system.deactivate_timer(timer_index);
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return;
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}
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BX_ASSERT(timer_index >= 0);
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BX_ASSERT(timer_index < BX_MAX_VIRTUAL_TIMERS);
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//No need to prevent doing this to unused/inactive timers.
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timer[timer_index].active = 0;
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}
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void
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bx_virt_timer_c::advance_virtual_time(Bit64u time_passed) {
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BX_ASSERT(time_passed <= virtual_next_event_time);
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current_virtual_time += time_passed;
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virtual_next_event_time -= time_passed;
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if(current_virtual_time > current_timers_time) {
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periodic(current_virtual_time - current_timers_time);
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}
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}
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//Called when next_event_time changes.
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void
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bx_virt_timer_c::next_event_time_update(void) {
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virtual_next_event_time = timers_next_event_time + current_timers_time - current_virtual_time;
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if(init_done) {
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bx_pc_system.deactivate_timer(system_timer_id);
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BX_ASSERT(virtual_next_event_time);
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bx_pc_system.activate_timer(system_timer_id,
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(Bit32u)BX_MIN(0x7FFFFFFF,BX_MAX(1,TICKS_TO_USEC(virtual_next_event_time))),
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0);
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}
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}
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void
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bx_virt_timer_c::init(void) {
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if ( (bx_options.clock.Osync->get ()!=BX_CLOCK_SYNC_REALTIME)
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&& (bx_options.clock.Osync->get ()!=BX_CLOCK_SYNC_BOTH) )
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virtual_timers_realtime = 0;
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else
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virtual_timers_realtime = 1;
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if (virtual_timers_realtime) {
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BX_INFO(("using 'realtime pit' synchronization method"));
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}
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register_timer(this, nullTimer, (Bit32u)NullTimerInterval, 1, 1, "Null Timer");
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system_timer_id = bx_pc_system.register_timer(this, pc_system_timer_handler,
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(Bit32u)virtual_next_event_time, 0, 1, "Virtual Timer");
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//Real time variables:
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#if BX_HAVE_REALTIME_USEC
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last_real_time=GET_VIRT_REALTIME64_USEC()+(Bit64u)TIME_HEADSTART*(Bit64u)USEC_PER_SECOND;
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#endif
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total_real_usec=0;
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last_realtime_delta=0;
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//System time variables:
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last_usec = 0
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;
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usec_per_second = USEC_PER_SECOND;
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stored_delta=0;
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last_system_usec=0;
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em_last_realtime=0;
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//Virtual timer variables:
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total_ticks=0;
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last_realtime_ticks=0;
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ticks_per_second = USEC_PER_SECOND;
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init_done = 1;
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}
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void
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bx_virt_timer_c::timer_handler(void) {
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if(!virtual_timers_realtime) {
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Bit64u temp_final_time = bx_pc_system.time_usec();
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temp_final_time-=current_virtual_time;
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while(temp_final_time) {
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if((temp_final_time)>(virtual_next_event_time)) {
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temp_final_time-=virtual_next_event_time;
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advance_virtual_time(virtual_next_event_time);
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} else {
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advance_virtual_time(temp_final_time);
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temp_final_time-=temp_final_time;
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}
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}
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bx_pc_system.activate_timer(system_timer_id,
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(Bit32u)BX_MIN(0x7FFFFFFF,(virtual_next_event_time>2)?(virtual_next_event_time-2):1),
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0);
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return;
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}
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Bit64u usec_delta = bx_pc_system.time_usec()-last_usec;
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if (usec_delta) {
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#if BX_HAVE_REALTIME_USEC
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Bit64u ticks_delta = 0;
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Bit64u real_time_delta = GET_VIRT_REALTIME64_USEC() - last_real_time;
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Bit64u real_time_total = real_time_delta + total_real_usec;
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Bit64u system_time_delta = (Bit64u)usec_delta + (Bit64u)stored_delta;
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if(real_time_delta) {
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last_realtime_delta = real_time_delta;
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last_realtime_ticks = total_ticks;
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}
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ticks_per_second = USEC_PER_SECOND;
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//Start out with the number of ticks we would like
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// to have to line up with real time.
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ticks_delta = real_time_total - total_ticks;
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if(real_time_total < total_ticks) {
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//This slows us down if we're already ahead.
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// probably only an issue on startup, but it solves some problems.
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ticks_delta = 0;
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}
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if(ticks_delta + total_ticks - last_realtime_ticks > (F2I(MAX_MULT * I2F(last_realtime_delta)))) {
|
|
//This keeps us from going too fast in relation to real time.
|
|
#if 0
|
|
ticks_delta = (F2I(MAX_MULT * I2F(last_realtime_delta))) + last_realtime_ticks - total_ticks;
|
|
#endif
|
|
ticks_per_second = F2I(MAX_MULT * I2F(USEC_PER_SECOND));
|
|
}
|
|
if(ticks_delta > system_time_delta * USEC_PER_SECOND / MIN_USEC_PER_SECOND) {
|
|
//This keeps us from having too few instructions between ticks.
|
|
ticks_delta = system_time_delta * USEC_PER_SECOND / MIN_USEC_PER_SECOND;
|
|
}
|
|
if(ticks_delta > virtual_next_event_time) {
|
|
//This keeps us from missing ticks.
|
|
ticks_delta = virtual_next_event_time;
|
|
}
|
|
|
|
if(ticks_delta) {
|
|
|
|
# if DEBUG_REALTIME_WITH_PRINTF
|
|
//Every second print some info.
|
|
if(((last_real_time + real_time_delta) / USEC_PER_SECOND) > (last_real_time / USEC_PER_SECOND)) {
|
|
Bit64u temp1, temp2, temp3, temp4;
|
|
temp1 = (Bit64u) total_real_usec;
|
|
temp2 = (total_real_usec);
|
|
temp3 = (Bit64u)total_ticks;
|
|
temp4 = (Bit64u)((total_real_usec) - total_ticks);
|
|
printf("useconds: %llu, ",temp1);
|
|
printf("expect ticks: %llu, ",temp2);
|
|
printf("ticks: %llu, ",temp3);
|
|
printf("diff: %llu\n",temp4);
|
|
}
|
|
# endif
|
|
|
|
last_real_time += real_time_delta;
|
|
total_real_usec += real_time_delta;
|
|
last_system_usec += system_time_delta;
|
|
stored_delta = 0;
|
|
total_ticks += ticks_delta;
|
|
} else {
|
|
stored_delta = system_time_delta;
|
|
}
|
|
|
|
|
|
Bit64u a,b;
|
|
a=(usec_per_second);
|
|
if(real_time_delta) {
|
|
//FIXME
|
|
Bit64u em_realtime_delta = last_system_usec + stored_delta - em_last_realtime;
|
|
b=((Bit64u)USEC_PER_SECOND * em_realtime_delta / real_time_delta);
|
|
em_last_realtime = last_system_usec + stored_delta;
|
|
} else {
|
|
b=a;
|
|
}
|
|
usec_per_second = ALPHA_LOWER(a,b);
|
|
#else
|
|
BX_ASSERT(0);
|
|
#endif
|
|
#if BX_HAVE_REALTIME_USEC
|
|
advance_virtual_time(ticks_delta);
|
|
#endif
|
|
}
|
|
|
|
last_usec=last_usec + usec_delta;
|
|
bx_pc_system.deactivate_timer(system_timer_id);
|
|
BX_ASSERT(virtual_next_event_time);
|
|
bx_pc_system.activate_timer(system_timer_id,
|
|
(Bit32u)BX_MIN(0x7FFFFFFF,BX_MAX(1,TICKS_TO_USEC(virtual_next_event_time))),
|
|
0);
|
|
|
|
}
|
|
|
|
void
|
|
bx_virt_timer_c::pc_system_timer_handler(void* this_ptr) {
|
|
((bx_virt_timer_c *)this_ptr)->timer_handler();
|
|
}
|
|
|