// for emergencies only! //------------------------------------------------- // eat_all_cycles - eat a ton of cycles on all // CPUs to force a quick exit //------------------------------------------------- public void eat_all_cycles() { for (device_execute_interface exec = m_execute_list; exec != null; exec = exec.nextexec) { exec.eat_cycles(1000000000); } }
// scheduling helpers //------------------------------------------------- // compute_perfect_interleave - compute the // "perfect" interleave interval //------------------------------------------------- public void compute_perfect_interleave() { // ensure we have a list of executing devices if (m_execute_list == null) { rebuild_execute_list(); } // start with the first one device_execute_interface first = m_execute_list; if (first != null) { // start with a huge time factor and find the 2nd smallest cycle time attoseconds_t smallest = first.minimum_quantum(); attoseconds_t perfect = attotime.ATTOSECONDS_PER_SECOND - 1; for (device_execute_interface exec = first.nextexec; exec != null; exec = exec.nextexec) { // find the 2nd smallest cycle interval attoseconds_t curquantum = exec.minimum_quantum(); if (curquantum < smallest) { perfect = smallest; smallest = curquantum; } else if (curquantum < perfect) { perfect = curquantum; } } // if this is a new minimum quantum, apply it if (m_quantum_minimum != perfect) { // adjust all the actuals; this doesn't affect the current m_quantum_minimum = perfect; for (quantum_slot quant = m_quantum_list.first(); quant != null; quant = quant.next()) { quant.actual_set(Math.Max(quant.requested(), m_quantum_minimum)); } } } }
//------------------------------------------------- // apply_suspend_changes - applies suspend/resume // changes to all device_execute_interfaces //------------------------------------------------- void apply_suspend_changes() { u32 suspendchanged = 0; for (device_execute_interface exec = m_execute_list; exec != null; exec = exec.nextexec) { suspendchanged |= exec.suspend_ ^ exec.nextsuspend; exec.suspend_ = exec.nextsuspend; exec.nextsuspend &= ~device_execute_interface.SUSPEND_REASON_TIMESLICE; exec.eatcycles = exec.nexteatcycles; } // recompute the execute list if any CPUs changed their suspension state if (suspendchanged != 0) { rebuild_execute_list(); } else { m_suspend_changes_pending = false; } }
//------------------------------------------------- // rebuild_execute_list - rebuild the list of // executing CPUs, moving suspended CPUs to the // end //------------------------------------------------- void rebuild_execute_list() { // if we haven't yet set a scheduling quantum, do it now if (m_quantum_list.empty()) { // set the core scheduling quantum attotime min_quantum = machine().config().minimum_quantum; // if none specified default to 60Hz if (min_quantum.is_zero()) { min_quantum = attotime.from_hz(60); } // if the configuration specifies a device to make perfect, pick that as the minimum if (!machine().config().perfect_cpu_quantum().empty()) { device_t device = machine().root_device().subdevice(machine().config().perfect_cpu_quantum().c_str()); if (device == null) { fatalerror("Device '{0}' specified for perfect interleave is not present!\n", machine().config().perfect_cpu_quantum()); } device_execute_interface exec; if (!device.interface_(out exec)) { fatalerror("Device '{0}' specified for perfect interleave is not an executing device!\n", machine().config().perfect_cpu_quantum()); } min_quantum = attotime.Min(new attotime(0, exec.minimum_quantum()), min_quantum); } // make sure it's no higher than 60Hz min_quantum = attotime.Min(min_quantum, attotime.from_hz(60)); // inform the timer system of our decision add_scheduling_quantum(min_quantum, attotime.never); } // start with an empty list //device_execute_interface **active_tailptr = &m_execute_list; //*active_tailptr = NULL; // also make an empty list of suspended devices //device_execute_interface *suspend_list = NULL; //device_execute_interface **suspend_tailptr = &suspend_list; List <device_execute_interface> active_list = new List <device_execute_interface>(); List <device_execute_interface> suspend_list = new List <device_execute_interface>(); // iterate over all devices foreach (device_execute_interface exec in new execute_interface_iterator(machine().root_device())) { // append to the appropriate list exec.nextexec = null; if (exec.suspend_ == 0) { //*active_tailptr = exec; //active_tailptr = &exec.m_nextexec; active_list.Add(exec); } else { //*suspend_tailptr = exec; //suspend_tailptr = &exec.m_nextexec; suspend_list.Add(exec); } } // append the suspend list to the end of the active list //*active_tailptr = suspend_list; active_list.AddRange(suspend_list); if (active_list.Count > 0) { m_execute_list = active_list[0]; for (int i = 0; i < active_list.Count; i++) { if (i < active_list.Count - 1) { active_list[i].nextexec = active_list[i + 1]; } else { active_list[i].nextexec = null; } } } }
// execution //------------------------------------------------- // timeslice - execute all devices for a single // timeslice //------------------------------------------------- public void timeslice() { bool call_debugger = (machine().debug_flags_get & machine_global.DEBUG_FLAG_ENABLED) != 0; // build the execution list if we don't have one yet //if (UNEXPECTED(m_execute_list == null)) if (m_execute_list == null) { rebuild_execute_list(); } // if the current quantum has expired, find a new one while (m_basetime >= m_quantum_list.first().expire()) { m_quantum_allocator.reclaim(m_quantum_list.detach_head()); } // loop until we hit the next timer while (m_basetime < m_timer_list.expire()) { // by default, assume our target is the end of the next quantum attotime target = m_basetime + new attotime(0, m_quantum_list.first().actual()); // however, if the next timer is going to fire before then, override if (m_timer_list.expire() < target) { target = m_timer_list.expire(); } if (machine().video().frame_update_count() % 1000 == 0) { //LOG(("------------------\n")); LOG("device_scheduler.timeslice() - cpu_timeslice: target = {0}, m_timer_list.expire: {1}\n", target.as_string(), m_timer_list.expire().as_string()); } // do we have pending suspension changes? if (m_suspend_changes_pending) { apply_suspend_changes(); } // loop over all CPUs for (device_execute_interface exec = m_execute_list; exec != null; exec = exec.nextexec) { // only process if this CPU is executing or truly halted (not yielding) // and if our target is later than the CPU's current time (coarse check) //if (EXPECTED((exec.m_suspend == 0 || exec.m_eatcycles) && target.seconds >= exec.m_localtime.seconds)) if ((exec.suspend_ == 0 || exec.eatcycles > 0) && target.seconds() >= exec.localtime.seconds()) { // compute how many attoseconds to execute this CPU attoseconds_t delta = target.attoseconds() - exec.localtime.attoseconds(); if (delta < 0 && target.seconds() > exec.localtime.seconds()) { delta += attotime.ATTOSECONDS_PER_SECOND; } assert(delta == (target - exec.localtime).as_attoseconds()); if (exec.attoseconds_per_cycle == 0) { exec.localtime = target; } // if we have enough for at least 1 cycle, do the math else if (delta >= exec.attoseconds_per_cycle) { // compute how many cycles we want to execute int ran = exec.cycles_running = (int)divu_64x32((UInt64)delta >> exec.divshift, (UInt32)exec.divisor); if (machine().video().frame_update_count() % 1000 == 0) { LOG("device_scheduler.timeslice() - cpu '{0}': {1} ({2} cycles)\n", exec.device().tag(), delta, exec.cycles_running); } // if we're not suspended, actually execute if (exec.suspend_ == 0) { profiler_global.g_profiler.start(exec.profiler); // note that this global variable cycles_stolen can be modified // via the call to cpu_execute exec.cycles_stolen = 0; m_executing_device = exec; exec.icount_set(exec.cycles_running); // *exec->m_icountptr = exec->m_cycles_running; if (!call_debugger) { exec.run(); } else { exec.debugger_start_cpu_hook(target); exec.run(); exec.debugger_stop_cpu_hook(); } // adjust for any cycles we took back /*assert(ran >= *exec->m_icountptr);*/ ran -= exec.icountptrRef.i; /*assert(ran >= exec->m_cycles_stolen);*/ ran -= exec.cycles_stolen; profiler_global.g_profiler.stop(); } // account for these cycles exec.totalcycles += (UInt64)ran; // update the local time for this CPU attotime deltatime; if (ran < exec.cycles_per_second) { deltatime = new attotime(0, exec.attoseconds_per_cycle * ran); } else { UInt32 remainder; int secs = (int)divu_64x32_rem((UInt64)ran, exec.cycles_per_second, out remainder); deltatime = new attotime(secs, remainder * exec.attoseconds_per_cycle); } assert(deltatime >= attotime.zero); exec.localtime += deltatime; if (machine().video().frame_update_count() % 100 == 0) { LOG("device_scheduler.timeslice() - {0} ran, {1} total, time = {2}\n", ran, exec.totalcycles, exec.localtime.as_string()); } // if the new local CPU time is less than our target, move the target up, but not before the base if (exec.localtime < target) { target = attotime.Max(exec.localtime, m_basetime); if (machine().video().frame_update_count() % 1000 == 0) { LOG("device_scheduler.timeslice() - (new target)\n"); } } } } } m_executing_device = null; // update the base time m_basetime = target; } // execute timers execute_timers(); }