summaryrefslogblamecommitdiffstatshomepage
path: root/src/emu/cpuexec.c
blob: eebe6a89398f2248820f0f389f28f22b4084172e (plain) (tree)
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996






























                                                                            
                                                         

























































                                                                                                             
                                                                                                                    












































































































                                                                                                                                                                                                               

                                                             







































































































































































                                                                                                                                            
                                                                                      
















































































































































































































































































































































































































































































































































































































































                                                                                                                                                                       
                                                                     














































                                                             















                                                       















                                                 








                                                             




















                                                                  


















































































                                                                                                       
                                                 
























































                                                                                                                                                                                            
                                                  




























                                                                                                          
                                          




























































































                                                                                                                                                         
                                                                                                                                     



















                                                                                
                                                                   


                                                                             

                                                                             













































                                                                                                                     
                                                             













                                                                                              
                                                                      




                                                                                                                         
                                                                                             









                                                                                                                                   
                                                      

                                                                     
                                                                




                                                                       
/***************************************************************************

    cpuexec.c

    Core multi-CPU execution engine.

    Copyright (c) 1996-2007, Nicola Salmoria and the MAME Team.
    Visit http://mamedev.org for licensing and usage restrictions.

***************************************************************************/

#include <math.h>
#include "driver.h"
#include "cheat.h"
#include "profiler.h"
#include "debugger.h"

#ifdef MAME_DEBUG
#include "debug/debugcpu.h"
#endif



/*************************************
 *
 *  Debug logging
 *
 *************************************/

#define VERBOSE 0

#define LOG(x)	do { if (VERBOSE) logerror x; } while (0)



/*************************************
 *
 *  Macros to help verify active CPU
 *
 *************************************/

#define VERIFY_ACTIVECPU(name) \
	int activecpu = cpu_getactivecpu(); \
	assert_always(activecpu >= 0, #name "() called with no active cpu!")

#define VERIFY_EXECUTINGCPU(name) \
	int activecpu = cpu_getexecutingcpu(); \
	assert_always(activecpu >= 0, #name "() called with no executing cpu!")

#define VERIFY_CPUNUM(name) \
	assert_always(cpunum >= 0 && cpunum < cpu_gettotalcpu(), #name "() called for invalid cpu num!")



/*************************************
 *
 *  Triggers for the timer system
 *
 *************************************/

enum
{
	TRIGGER_TIMESLICE 	= -1000,
	TRIGGER_INT 		= -2000,
	TRIGGER_YIELDTIME 	= -3000,
	TRIGGER_SUSPENDTIME = -4000
};



/*************************************
 *
 *  Internal CPU info structure
 *
 *************************************/

typedef struct _cpuexec_data cpuexec_data;
struct _cpuexec_data
{
	UINT8	saveable;				/* true if saveable */

	UINT8	suspend;				/* suspend reason mask (0 = not suspended) */
	UINT8	nextsuspend;			/* pending suspend reason mask */
	UINT8	eatcycles;				/* true if we eat cycles while suspended */
	UINT8	nexteatcycles;			/* pending value */
	INT32	trigger;				/* pending trigger to release a trigger suspension */

	INT32 	iloops; 				/* number of interrupts remaining this frame */

	UINT64 	totalcycles;			/* total CPU cycles executed */
	attotime localtime;				/* local time, relative to the timer system's global time */
	INT32	clock;					/* current active clock */
	double	clockscale;				/* current active clock scale factor */

	INT32	vblankint_countdown;	/* number of vblank callbacks left until we interrupt */
	INT32 	vblankint_multiplier;	/* number of vblank callbacks per interrupt */
	void *	vblankint_timer;		/* reference to elapsed time counter */

	void *	timedint_timer;			/* reference to this CPU's timer */
	attotime timedint_period; 		/* timing period of the timed interrupt */
};



/*************************************
 *
 *  General CPU variables
 *
 *************************************/

static cpuexec_data cpu[MAX_CPU];

static UINT8 vblank;
static UINT32 current_frame;
static INT32 watchdog_counter;

static int cycles_running;
static int cycles_stolen;



/*************************************
 *
 *  Timer variables
 *
 *************************************/

static emu_timer *vblank_timer;
static INT32 vblank_countdown;
static INT32 vblank_multiplier;
static attotime vblank_period;

static emu_timer *update_timer;

emu_timer *refresh_timer;	/* temporarily made non-static (for ccpu) */
static attotime refresh_period;

static emu_timer *timeslice_timer;
static attotime timeslice_period;

static emu_timer *interleave_boost_timer;
static emu_timer *interleave_boost_timer_end;
static attotime perfect_interleave;

static emu_timer *watchdog_timer;



/*************************************
 *
 *  Static prototypes
 *
 *************************************/

static void cpuexec_exit(running_machine *machine);
static void cpuexec_reset(running_machine *machine);
static void cpu_inittimers(running_machine *machine);
static void cpu_vblankreset(void);
static TIMER_CALLBACK( cpu_vblankcallback );
static TIMER_CALLBACK( cpu_updatecallback );
static TIMER_CALLBACK( end_interleave_boost );
static void compute_perfect_interleave(void);
static void watchdog_setup(int alloc_new);



/*************************************
 *
 *  Watchdog Flags
 *
 *************************************/

#define WATCHDOG_IS_STARTED_DISABLED	-1
#define WATCHDOG_IS_DISABLED			-2
#define WATCHDOG_IS_TIMER_BASED			-3
#define WATCHDOG_IS_INVALID				-4
#define WATCHDOG_IS_BEING_STARTED		-5



#if 0
#pragma mark CORE CPU
#endif

/*************************************
 *
 *  Initialize all the CPUs
 *
 *************************************/

void cpuexec_init(running_machine *machine)
{
	int cpunum;

	/* if there has been no VBLANK time specified in the MACHINE_DRIVER, compute it now
       from the visible area */
	if (machine->screen[0].vblank == 0 && !machine->screen[0].oldstyle_vblank_supplied)
		machine->screen[0].vblank = (machine->screen[0].refresh / machine->screen[0].height) * (machine->screen[0].height - (machine->screen[0].visarea.max_y + 1 - machine->screen[0].visarea.min_y));

	/* allocate vblank and refresh timers, and compute the initial timing */
	vblank_timer = timer_alloc(cpu_vblankcallback, NULL);
	refresh_timer = timer_alloc(NULL, NULL);
	cpu_compute_vblank_timing();

	/* loop over all our CPUs */
	for (cpunum = 0; cpunum < MAX_CPU; cpunum++)
	{
		cpu_type cputype = machine->drv->cpu[cpunum].type;
		int num_regs;

		/* if this is a dummy, stop looking */
		if (cputype == CPU_DUMMY)
			break;

		/* initialize the cpuinfo struct */
		memset(&cpu[cpunum], 0, sizeof(cpu[cpunum]));
		cpu[cpunum].suspend = SUSPEND_REASON_RESET;
		cpu[cpunum].clock = machine->drv->cpu[cpunum].clock;
		cpu[cpunum].clockscale = 1.0;
		cpu[cpunum].localtime = attotime_zero;

		/* compute the cycle times */
		cycles_per_second[cpunum] = cpu[cpunum].clockscale * cpu[cpunum].clock;
		attoseconds_per_cycle[cpunum] = ATTOSECONDS_PER_SECOND / (cpu[cpunum].clockscale * cpu[cpunum].clock);

		/* register some of our variables for later */
		state_save_register_item("cpu", cpunum, cpu[cpunum].suspend);
		state_save_register_item("cpu", cpunum, cpu[cpunum].nextsuspend);
		state_save_register_item("cpu", cpunum, cpu[cpunum].eatcycles);
		state_save_register_item("cpu", cpunum, cpu[cpunum].nexteatcycles);
		state_save_register_item("cpu", cpunum, cpu[cpunum].trigger);

		state_save_register_item("cpu", cpunum, cpu[cpunum].iloops);

		state_save_register_item("cpu", cpunum, cpu[cpunum].totalcycles);
		state_save_register_item("cpu", cpunum, cpu[cpunum].localtime.seconds);
		state_save_register_item("cpu", cpunum, cpu[cpunum].localtime.attoseconds);
		state_save_register_item("cpu", cpunum, cpu[cpunum].clock);
		state_save_register_item("cpu", cpunum, cpu[cpunum].clockscale);

		state_save_register_item("cpu", cpunum, cpu[cpunum].vblankint_countdown);

		/* initialize this CPU */
		state_save_push_tag(cpunum + 1);
		num_regs = state_save_get_reg_count();
		if (cpuintrf_init_cpu(cpunum, cputype, cpu[cpunum].clock, machine->drv->cpu[cpunum].reset_param, cpu_irq_callbacks[cpunum]))
			fatalerror("Unable to initialize CPU #%d (%s)", cpunum, cputype_name(cputype));
		num_regs = state_save_get_reg_count() - num_regs;
		state_save_pop_tag();

		/* if no state registered for saving, we can't save */
		if (num_regs == 0)
		{
			logerror("CPU #%d (%s) did not register any state to save!\n", cpunum, cputype_name(cputype));
			if (machine->gamedrv->flags & GAME_SUPPORTS_SAVE)
				fatalerror("CPU #%d (%s) did not register any state to save!", cpunum, cputype_name(cputype));
		}
	}
	add_reset_callback(machine, cpuexec_reset);
	add_exit_callback(machine, cpuexec_exit);

	/* compute the perfect interleave factor */
	compute_perfect_interleave();

	/* save some stuff in the default tag */
	state_save_push_tag(0);
	state_save_register_item("cpu", 0, vblank);
	state_save_register_item("cpu", 0, current_frame);
	state_save_register_item("cpu", 0, watchdog_counter);
	state_save_register_item("cpu", 0, vblank_countdown);
	state_save_pop_tag();
}



/*************************************
 *
 *  Prepare the system for execution
 *
 *************************************/

static void cpuexec_reset(running_machine *machine)
{
	int cpunum;

	/* initialize the various timers (suspends all CPUs at startup) */
	cpu_inittimers(machine);
	watchdog_counter = WATCHDOG_IS_INVALID;
	watchdog_setup(TRUE);

	/* first pass over CPUs */
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
	{
		/* enable all CPUs (except for disabled CPUs) */
		if (!(machine->drv->cpu[cpunum].flags & CPU_DISABLE))
			cpunum_resume(cpunum, SUSPEND_ANY_REASON);
		else
			cpunum_suspend(cpunum, SUSPEND_REASON_DISABLE, 1);

		/* reset the total number of cycles */
		cpu[cpunum].totalcycles = 0;

		/* then reset the CPU directly */
		cpunum_reset(cpunum);
	}

	/* reset the globals */
	cpu_vblankreset();
	vblank = 0;
	current_frame = 0;
}



/*************************************
 *
 *  Deinitialize all the CPUs
 *
 *************************************/

static void cpuexec_exit(running_machine *machine)
{
	int cpunum;

	/* shut down the CPU cores */
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
		cpuintrf_exit_cpu(cpunum);
}




#if 0
#pragma mark -
#pragma mark WATCHDOG
#endif

/*************************************
 *
 *  Watchdog timer callback
 *
 *************************************/

static TIMER_CALLBACK( watchdog_callback )
{
	logerror("reset caused by the (time) watchdog\n");
	mame_schedule_soft_reset(machine);
}



/*************************************
 *
 *  Watchdog setup routine
 *
 *************************************/

static void watchdog_setup(int alloc_new)
{
	if (watchdog_counter != WATCHDOG_IS_DISABLED)
	{
		if (Machine->drv->watchdog_vblank_count)
		{
			/* Start a vblank based watchdog. */
			watchdog_counter = Machine->drv->watchdog_vblank_count;
		}
		else if (attotime_compare(Machine->drv->watchdog_time, attotime_zero) != 0)
		{
			/* Start a time based watchdog. */
			if (alloc_new)
				watchdog_timer = timer_alloc(watchdog_callback, NULL);
			timer_adjust(watchdog_timer, Machine->drv->watchdog_time, 0, attotime_zero);
			watchdog_counter = WATCHDOG_IS_TIMER_BASED;
		}
		else if (watchdog_counter == WATCHDOG_IS_INVALID)
		{
			/* The watchdog was not initialized in the MACHINE_DRIVER,
             * so we will start with it disabled.
             */
			watchdog_counter = WATCHDOG_IS_STARTED_DISABLED;
		}
		else
		{
			/* The watchdog was not initialized in the MACHINE_DRIVER.
             * But it has been manually started, so we will default to
             * using a vblank watchdog.  We will set up a default time
             * of 3 times the refresh rate.  Which is 3 seconds @ 60Hz
             * refresh.

             * The 3 seconds delay is targeted at qzshowby, which otherwise
             * would reset at the start of a game.
             */
			watchdog_counter = 3 * ATTOSECONDS_TO_HZ(Machine->screen[0].refresh);
		}
	}
}



/*************************************
 *
 *  Watchdog reset
 *
 *************************************/

void watchdog_reset(void)
{
	if (watchdog_counter == WATCHDOG_IS_TIMER_BASED)
	{
		timer_reset(watchdog_timer, Machine->drv->watchdog_time);
	}
	else
	{
		if (watchdog_counter == WATCHDOG_IS_STARTED_DISABLED)
		{
			watchdog_counter = WATCHDOG_IS_BEING_STARTED;
			logerror("(vblank) watchdog armed by reset\n");
		}

		watchdog_setup(FALSE);
	}
}



/*************************************
 *
 *  Watchdog enable/disable
 *
 *************************************/

void watchdog_enable(int enable)
{
	if (!enable)
	{
		// Disable all timers
		watchdog_counter = WATCHDOG_IS_DISABLED;
	}
	else
	// Setup only on change from disable to enable.
	// Do not setup if watchdog is disabled from machine init.
	if (watchdog_counter == WATCHDOG_IS_DISABLED)
	{
		watchdog_counter = WATCHDOG_IS_BEING_STARTED;
		watchdog_setup(FALSE);
	}
}



#if 0
#pragma mark -
#pragma mark CPU SCHEDULING
#endif

/*************************************
 *
 *  Execute all the CPUs for one
 *  timeslice
 *
 *************************************/

void cpuexec_timeslice(void)
{
	attotime target = timer_next_fire_time();
	attotime base = timer_get_time();
	int cpunum, ran;

	LOG(("------------------\n"));
	LOG(("cpu_timeslice: target = %s\n", attotime_string(target, 9)));

	/* process any pending suspends */
	for (cpunum = 0; Machine->drv->cpu[cpunum].type != CPU_DUMMY; cpunum++)
	{
		if (cpu[cpunum].suspend != cpu[cpunum].nextsuspend)
			LOG(("--> updated CPU%d suspend from %X to %X\n", cpunum, cpu[cpunum].suspend, cpu[cpunum].nextsuspend));
		cpu[cpunum].suspend = cpu[cpunum].nextsuspend;
		cpu[cpunum].eatcycles = cpu[cpunum].nexteatcycles;
	}

	/* loop over CPUs */
	for (cpunum = 0; Machine->drv->cpu[cpunum].type != CPU_DUMMY; cpunum++)
	{
		/* only process if we're not suspended */
		if (!cpu[cpunum].suspend)
		{
			/* compute how long to run */
			cycles_running = ATTOTIME_TO_CYCLES(cpunum, attotime_sub(target, cpu[cpunum].localtime));
			LOG(("  cpu %d: %d cycles\n", cpunum, cycles_running));

			/* run for the requested number of cycles */
			if (cycles_running > 0)
			{
				profiler_mark(PROFILER_CPU1 + cpunum);

				/* note that this global variable cycles_stolen can be modified */
				/* via the call to the cpunum_execute */
				cycles_stolen = 0;
				ran = cpunum_execute(cpunum, cycles_running);

#ifdef MAME_DEBUG
				if (ran < cycles_stolen)
					fatalerror("Negative CPU cycle count!");
#endif /* MAME_DEBUG */

				ran -= cycles_stolen;
				profiler_mark(PROFILER_END);

				/* account for these cycles */
				cpu[cpunum].totalcycles += ran;
				cpu[cpunum].localtime = attotime_add(cpu[cpunum].localtime, ATTOTIME_IN_CYCLES(ran, cpunum));
				LOG(("         %d ran, %d total, time = %s\n", ran, (INT32)cpu[cpunum].totalcycles, attotime_string(cpu[cpunum].localtime, 9)));

				/* if the new local CPU time is less than our target, move the target up */
				if (attotime_compare(cpu[cpunum].localtime, target) < 0)
				{
					if (attotime_compare(cpu[cpunum].localtime, base) > 0)
						target = cpu[cpunum].localtime;
					else
						target = base;
					LOG(("         (new target)\n"));
				}
			}
		}
	}

	/* update the local times of all CPUs */
	for (cpunum = 0; Machine->drv->cpu[cpunum].type != CPU_DUMMY; cpunum++)
	{
		/* if we're suspended and counting, process */
		if (cpu[cpunum].suspend && cpu[cpunum].eatcycles && attotime_compare(cpu[cpunum].localtime, target) < 0)
		{
			/* compute how long to run */
			cycles_running = ATTOTIME_TO_CYCLES(cpunum, attotime_sub(target, cpu[cpunum].localtime));
			LOG(("  cpu %d: %d cycles (suspended)\n", cpunum, cycles_running));

			cpu[cpunum].totalcycles += cycles_running;
			cpu[cpunum].localtime = attotime_add(cpu[cpunum].localtime, ATTOTIME_IN_CYCLES(cycles_running, cpunum));
			LOG(("         %d skipped, %d total, time = %s\n", cycles_running, (INT32)cpu[cpunum].totalcycles, attotime_string(cpu[cpunum].localtime, 9)));
		}

		/* update the suspend state */
		if (cpu[cpunum].suspend != cpu[cpunum].nextsuspend)
			LOG(("--> updated CPU%d suspend from %X to %X\n", cpunum, cpu[cpunum].suspend, cpu[cpunum].nextsuspend));
		cpu[cpunum].suspend = cpu[cpunum].nextsuspend;
		cpu[cpunum].eatcycles = cpu[cpunum].nexteatcycles;
	}

	/* update the global time */
	timer_set_global_time(target);
}



/*************************************
 *
 *  Abort the timeslice for the
 *  active CPU
 *
 *************************************/

void activecpu_abort_timeslice(void)
{
	int current_icount;

	VERIFY_EXECUTINGCPU(activecpu_abort_timeslice);
	LOG(("activecpu_abort_timeslice (CPU=%d, cycles_left=%d)\n", cpu_getexecutingcpu(), activecpu_get_icount() + 1));

	/* swallow the remaining cycles */
	current_icount = activecpu_get_icount() + 1;
	cycles_stolen += current_icount;
	cycles_running -= current_icount;
	activecpu_adjust_icount(-current_icount);
}



/*************************************
 *
 *  Return the current local time for
 *  a CPU, relative to the current
 *  timeslice
 *
 *************************************/

attotime cpunum_get_localtime(int cpunum)
{
	attotime result;

	VERIFY_CPUNUM(cpunum_get_localtime);

	/* if we're active, add in the time from the current slice */
	result = cpu[cpunum].localtime;
	if (cpunum == cpu_getexecutingcpu())
	{
		int cycles = cycles_currently_ran();
		result = attotime_add(result, ATTOTIME_IN_CYCLES(cycles, cpunum));
	}
	return result;
}



/*************************************
 *
 *  Set a suspend reason for the
 *  given CPU
 *
 *************************************/

void cpunum_suspend(int cpunum, int reason, int eatcycles)
{
	VERIFY_CPUNUM(cpunum_suspend);
	LOG(("cpunum_suspend (CPU=%d, r=%X, eat=%d)\n", cpunum, reason, eatcycles));

	/* set the pending suspend bits, and force a resync */
	cpu[cpunum].nextsuspend |= reason;
	cpu[cpunum].nexteatcycles = eatcycles;
	if (cpu_getexecutingcpu() >= 0)
		activecpu_abort_timeslice();
}



/*************************************
 *
 *  Clear a suspend reason for a
 *  given CPU
 *
 *************************************/

void cpunum_resume(int cpunum, int reason)
{
	VERIFY_CPUNUM(cpunum_resume);
	LOG(("cpunum_resume (CPU=%d, r=%X)\n", cpunum, reason));

	/* clear the pending suspend bits, and force a resync */
	cpu[cpunum].nextsuspend &= ~reason;
	if (cpu_getexecutingcpu() >= 0)
		activecpu_abort_timeslice();
}



/*************************************
 *
 *  Return true if a given CPU is
 *  suspended
 *
 *************************************/

int cpunum_is_suspended(int cpunum, int reason)
{
	VERIFY_CPUNUM(cpunum_suspend);
	return ((cpu[cpunum].nextsuspend & reason) != 0);
}



/*************************************
 *
 *  Gets the current CPU's clock speed
 *
 *************************************/

int cpunum_get_clock(int cpunum)
{
	VERIFY_CPUNUM(cpunum_get_clock);
	return cpu[cpunum].clock;
}



/*************************************
 *
 *  Sets the current CPU's clock speed
 *
 *************************************/

void cpunum_set_clock(int cpunum, int clock)
{
	VERIFY_CPUNUM(cpunum_set_clock);

	cpu[cpunum].clock = clock;
	cycles_per_second[cpunum] = (double)clock * cpu[cpunum].clockscale;
	attoseconds_per_cycle[cpunum] = ATTOSECONDS_PER_SECOND / ((double)clock * cpu[cpunum].clockscale);

	/* re-compute the perfect interleave factor */
	compute_perfect_interleave();
}



void cpunum_set_clock_period(int cpunum, attoseconds_t clock_period)
{
	VERIFY_CPUNUM(cpunum_set_clock);

	cpu[cpunum].clock = ATTOSECONDS_PER_SECOND / clock_period;
	cycles_per_second[cpunum] = (double) (ATTOSECONDS_PER_SECOND / clock_period) * cpu[cpunum].clockscale;
	attoseconds_per_cycle[cpunum] = clock_period;

	/* re-compute the perfect interleave factor */
	compute_perfect_interleave();
}



/*************************************
 *
 *  Returns the current scaling factor
 *  for a CPU's clock speed
 *
 *************************************/

double cpunum_get_clockscale(int cpunum)
{
	VERIFY_CPUNUM(cpunum_get_clockscale);
	return cpu[cpunum].clockscale;
}



/*************************************
 *
 *  Sets the current scaling factor
 *  for a CPU's clock speed
 *
 *************************************/

void cpunum_set_clockscale(int cpunum, double clockscale)
{
	VERIFY_CPUNUM(cpunum_set_clockscale);

	cpu[cpunum].clockscale = clockscale;
	cycles_per_second[cpunum] = (double)cpu[cpunum].clock * clockscale;
	attoseconds_per_cycle[cpunum] = ATTOSECONDS_PER_SECOND / ((double)cpu[cpunum].clock * clockscale);

	/* re-compute the perfect interleave factor */
	compute_perfect_interleave();
}



/*************************************
 *
 *  Temporarily boosts the interleave
 *  factor
 *
 *************************************/

void cpu_boost_interleave(attotime timeslice_time, attotime boost_duration)
{
	/* if you pass 0 for the timeslice_time, it means pick something reasonable */
	if (attotime_compare(timeslice_time, perfect_interleave) < 0)
		timeslice_time = perfect_interleave;

	LOG(("cpu_boost_interleave(%s, %s)\n", attotime_string(timeslice_time, 9), attotime_string(boost_duration, 9)));

	/* adjust the interleave timer */
	timer_adjust(interleave_boost_timer, timeslice_time, 0, timeslice_time);

	/* adjust the end timer, but only if we are going to extend it */
	if (!timer_enabled(interleave_boost_timer_end) || attotime_compare(timer_timeleft(interleave_boost_timer_end), boost_duration) < 0)
		timer_adjust(interleave_boost_timer_end, boost_duration, 0, attotime_never);
}



#if 0
#pragma mark -
#pragma mark TIMING HELPERS
#endif

/*************************************
 *
 *  Return cycles ran this iteration
 *
 *************************************/

int cycles_currently_ran(void)
{
	VERIFY_EXECUTINGCPU(cycles_currently_ran);
	return cycles_running - activecpu_get_icount();
}



/*************************************
 *
 *  Return total number of CPU cycles
 *  for the active CPU or for a given CPU.
 *
 *************************************/

/*--------------------------------------------------------------

    IMPORTANT: this value wraps around in a relatively short
    time. For example, for a 6MHz CPU, it will wrap around in
    2^32/6000000 = 716 seconds = 12 minutes.

    Make sure you don't do comparisons between values returned
    by this function, but only use the difference (which will
    be correct regardless of wraparound).

    Alternatively, use the new 64-bit variants instead.

--------------------------------------------------------------*/

UINT32 activecpu_gettotalcycles(void)
{
	VERIFY_ACTIVECPU(activecpu_gettotalcycles);
	if (activecpu == cpu_getexecutingcpu())
		return cpu[activecpu].totalcycles + cycles_currently_ran();
	else
		return cpu[activecpu].totalcycles;
}

UINT32 cpunum_gettotalcycles(int cpunum)
{
	VERIFY_CPUNUM(cpunum_gettotalcycles);
	if (cpunum == cpu_getexecutingcpu())
		return cpu[cpunum].totalcycles + cycles_currently_ran();
	else
		return cpu[cpunum].totalcycles;
}


UINT64 activecpu_gettotalcycles64(void)
{
	VERIFY_ACTIVECPU(activecpu_gettotalcycles64);
	if (activecpu == cpu_getexecutingcpu())
		return cpu[activecpu].totalcycles + cycles_currently_ran();
	else
		return cpu[activecpu].totalcycles;
}

UINT64 cpunum_gettotalcycles64(int cpunum)
{
	VERIFY_CPUNUM(cpunum_gettotalcycles64);
	if (cpunum == cpu_getexecutingcpu())
		return cpu[cpunum].totalcycles + cycles_currently_ran();
	else
		return cpu[cpunum].totalcycles;
}



/*************************************
 *
 *  Safely eats cycles so we don't
 *  cross a timeslice boundary
 *
 *************************************/

void activecpu_eat_cycles(int cycles)
{
	int cyclesleft = activecpu_get_icount();
	if (cycles > cyclesleft)
		cycles = cyclesleft;
	activecpu_adjust_icount(-cycles);
}



/*************************************
 *
 *  Scales a given value by the fraction
 *  of time elapsed between refreshes
 *
 *************************************/

int cpu_scalebyfcount(int value)
{
	attotime refresh_elapsed = timer_timeelapsed(refresh_timer);
	int result;

	/* shift off some bits to ensure no overflow */
	if (value < 65536)
		result = value * (refresh_elapsed.attoseconds >> 16) / (refresh_period.attoseconds >> 16);
	else
		result = value * (refresh_elapsed.attoseconds >> 32) / (refresh_period.attoseconds >> 32);
	if (value >= 0)
		return (result < value) ? result : value;
	else
		return (result > value) ? result : value;
}



#if 0
#pragma mark -
#pragma mark VIDEO TIMING
#endif

/*************************************
 *
 *  Computes the VBLANK timing
 *
 *************************************/

void cpu_compute_vblank_timing(void)
{
	refresh_period = attotime_make(0, Machine->screen[0].refresh);

	/* recompute the vblank period */
	vblank_period = attotime_make(0, Machine->screen[0].refresh / (vblank_multiplier ? vblank_multiplier : 1));
	if (vblank_timer != NULL && timer_enable(vblank_timer, FALSE))
	{
		attotime remaining = timer_timeleft(vblank_timer);
		if (remaining.seconds == 0 && remaining.attoseconds == 0)
			remaining = vblank_period;
		timer_adjust(vblank_timer, remaining, 0, vblank_period);
	}

	LOG(("cpu_compute_vblank_timing: refresh=%s vblank=%s\n", attotime_string(refresh_period, 9), attotime_string(vblank_period, 9)));
}



/*************************************
 *
 *  Returns the VBLANK state
 *
 *************************************/

int cpu_getvblank(void)
{
	return vblank;
}



/*************************************
 *
 *  Returns the current frame count
 *
 *************************************/

int cpu_getcurrentframe(void)
{
	return current_frame;
}



#if 0
#pragma mark -
#pragma mark SYNCHRONIZATION
#endif

/*************************************
 *
 *  Generate a specific trigger
 *
 *************************************/

void cpu_trigger(int trigger)
{
	int cpunum;

	/* cause an immediate resynchronization */
	if (cpu_getexecutingcpu() >= 0)
		activecpu_abort_timeslice();

	/* look for suspended CPUs waiting for this trigger and unsuspend them */
	for (cpunum = 0; cpunum < MAX_CPU; cpunum++)
	{
		/* if this is a dummy, stop looking */
		if (Machine->drv->cpu[cpunum].type == CPU_DUMMY)
			break;

		/* see if this is a matching trigger */
		if (cpu[cpunum].suspend && cpu[cpunum].trigger == trigger)
		{
			cpunum_resume(cpunum, SUSPEND_REASON_TRIGGER);
			cpu[cpunum].trigger = 0;
		}
	}
}



/*************************************
 *
 *  Generate a trigger in the future
 *
 *************************************/

static TIMER_CALLBACK( cpu_triggertime_callback )
{
	cpu_trigger(param);
}


void cpu_triggertime(attotime duration, int trigger)
{
	timer_set(duration, NULL, trigger, cpu_triggertime_callback);
}



/*************************************
 *
 *  Generate a trigger for an int
 *
 *************************************/

void cpu_triggerint(int cpunum)
{
	cpu_trigger(TRIGGER_INT + cpunum);
}



/*************************************
 *
 *  Burn/yield CPU cycles until a trigger
 *
 *************************************/

void cpu_spinuntil_trigger(int trigger)
{
	int cpunum = cpu_getexecutingcpu();

	VERIFY_EXECUTINGCPU(cpu_spinuntil_trigger);

	/* suspend the CPU immediately if it's not already */
	cpunum_suspend(cpunum, SUSPEND_REASON_TRIGGER, 1);

	/* set the trigger */
	cpu[cpunum].trigger = trigger;
}

void cpunum_spinuntil_trigger( int cpunum, int trigger )
{
	VERIFY_CPUNUM(cpunum_spinuntil_trigger);

	/* suspend the CPU immediately if it's not already */
	cpunum_suspend(cpunum, SUSPEND_REASON_TRIGGER, 1);

	/* set the trigger */
	cpu[cpunum].trigger = trigger;
}



/*************************************
 *
 *  Burn/yield CPU cycles until an
 *  interrupt
 *
 *************************************/

void cpu_spinuntil_int(void)
{
	VERIFY_EXECUTINGCPU(cpu_spinuntil_int);
	cpu_spinuntil_trigger(TRIGGER_INT + activecpu);
}



/*************************************
 *
 *  Burn/yield CPU cycles until the
 *  end of the current timeslice
 *
 *************************************/

void cpu_spin(void)
{
	cpu_spinuntil_trigger(TRIGGER_TIMESLICE);
}


void cpu_yield(void)
{
	int cpunum = cpu_getexecutingcpu();

	VERIFY_EXECUTINGCPU(cpu_yielduntil_trigger);

	/* suspend the CPU immediately if it's not already */
	cpunum_suspend(cpunum, SUSPEND_REASON_TRIGGER, 0);

	/* set the trigger */
	cpu[cpunum].trigger = TRIGGER_TIMESLICE;
}



/*************************************
 *
 *  Burn/yield CPU cycles for a
 *  specific period of time
 *
 *************************************/

void cpu_spinuntil_time(attotime duration)
{
	static int timetrig = 0;

	cpu_spinuntil_trigger(TRIGGER_SUSPENDTIME + timetrig);
	cpu_triggertime(duration, TRIGGER_SUSPENDTIME + timetrig);
	timetrig = (timetrig + 1) & 255;
}



#if 0
#pragma mark -
#pragma mark CORE TIMING
#endif

/*************************************
 *
 *  Returns the number of times the
 *  interrupt handler will be called
 *  before the end of the current
 *  video frame.
 *
 *************************************/

/*--------------------------------------------------------------

    This can be useful to interrupt handlers to synchronize
    their operation. If you call this from outside an interrupt
    handler, add 1 to the result, i.e. if it returns 0, it means
    that the interrupt handler will be called once.

--------------------------------------------------------------*/

int cpu_getiloops(void)
{
	VERIFY_ACTIVECPU(cpu_getiloops);
	return cpu[activecpu].iloops;
}



/*************************************
 *
 *  Hook for updating things on the
 *  real VBLANK (once per frame)
 *
 *************************************/

static void cpu_vblankreset(void)
{
	int cpunum;

	/* notify the video system of a VBLANK start */
	video_vblank_start(Machine);

	/* read keyboard & update the status of the input ports */
	input_port_vblank_start();

	/* check the watchdog */
	if (watchdog_counter > 0)
	{
		if (--watchdog_counter == 0)
		{
			logerror("reset caused by the (vblank) watchdog\n");
			mame_schedule_soft_reset(Machine);
		}
	}

	/* reset the cycle counters */
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
	{
		if (!(cpu[cpunum].suspend & SUSPEND_REASON_DISABLE))
			cpu[cpunum].iloops = Machine->drv->cpu[cpunum].vblank_interrupts_per_frame - 1;
		else
			cpu[cpunum].iloops = -1;
	}
}



/*************************************
 *
 *  First-run callback for VBLANKs
 *
 *************************************/

static TIMER_CALLBACK( cpu_firstvblankcallback )
{
	/* now that we're synced up, pulse from here on out */
	timer_adjust(vblank_timer, vblank_period, param, vblank_period);

	/* but we need to call the standard routine as well */
	cpu_vblankcallback(machine, NULL, param);
}



/*************************************
 *
 *  VBLANK core handler
 *
 *************************************/

static TIMER_CALLBACK( cpu_vblankcallback )
{
	int cpunum;

	if (vblank_countdown == 1)
		vblank = 1;

	/* loop over CPUs */
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
	{
		/* if the interrupt multiplier is valid */
		if (cpu[cpunum].vblankint_multiplier != -1)
		{
			/* decrement; if we hit zero, generate the interrupt and reset the countdown */
			if (!--cpu[cpunum].vblankint_countdown)
			{
				/* a param of -1 means don't call any callbacks */
				if (param != -1)
				{
					/* if the CPU has a VBLANK handler, call it */
					if (machine->drv->cpu[cpunum].vblank_interrupt && !cpunum_is_suspended(cpunum, SUSPEND_REASON_HALT | SUSPEND_REASON_RESET | SUSPEND_REASON_DISABLE))
					{
						cpuintrf_push_context(cpunum);
						(*machine->drv->cpu[cpunum].vblank_interrupt)();
						cpuintrf_pop_context();
					}

					/* update the counters */
					cpu[cpunum].iloops--;
				}

				/* reset the countdown and timer */
				cpu[cpunum].vblankint_countdown = cpu[cpunum].vblankint_multiplier;
				timer_adjust(cpu[cpunum].vblankint_timer, attotime_never, 0, attotime_never);
			}
		}

		/* else reset the VBLANK timer if this is going to be a real VBLANK */
		else if (vblank_countdown == 1)
			timer_adjust(cpu[cpunum].vblankint_timer, attotime_never, 0, attotime_never);
	}

	/* is it a real VBLANK? */
	if (!--vblank_countdown)
	{
		/* do we update the screen now? */
		if (!(machine->drv->video_attributes & VIDEO_UPDATE_AFTER_VBLANK))
			video_frame_update(FALSE);

		/* Set the timer to update the screen */
		timer_adjust(update_timer, attotime_make(0, machine->screen[0].vblank), 0, attotime_zero);

		/* reset the globals */
		cpu_vblankreset();

		/* reset the counter */
		vblank_countdown = vblank_multiplier;

#ifdef MAME_DEBUG
		/* notify the debugger */
		debug_vblank_hook();
#endif
	}
}



/*************************************
 *
 *  End-of-VBLANK callback
 *
 *************************************/

static TIMER_CALLBACK( cpu_updatecallback )
{
	/* update the screen if we didn't before */
	if (machine->drv->video_attributes & VIDEO_UPDATE_AFTER_VBLANK)
		video_frame_update(FALSE);
	vblank = 0;

	/* update IPT_VBLANK input ports */
	input_port_vblank_end();

	/* track total frames */
	current_frame++;

	/* reset the refresh timer */
	timer_adjust(refresh_timer, attotime_never, 0, attotime_never);
}



/*************************************
 *
 *  Callback for timed interrupts
 *  (not tied to a VBLANK)
 *
 *************************************/

static TIMER_CALLBACK( cpu_timedintcallback )
{
	/* bail if there is no routine */
	if (machine->drv->cpu[param].timed_interrupt && !cpunum_is_suspended(param, SUSPEND_REASON_HALT | SUSPEND_REASON_RESET | SUSPEND_REASON_DISABLE))
	{
		cpuintrf_push_context(param);
		(*machine->drv->cpu[param].timed_interrupt)();
		cpuintrf_pop_context();
	}
}



/*************************************
 *
 *  Callback to force a timeslice
 *
 *************************************/

static TIMER_CALLBACK( cpu_timeslicecallback )
{
	cpu_trigger(TRIGGER_TIMESLICE);
}



/*************************************
 *
 *  Callback to end a temporary
 *  interleave boost
 *
 *************************************/

static TIMER_CALLBACK( end_interleave_boost )
{
	timer_adjust(interleave_boost_timer, attotime_never, 0, attotime_never);
	LOG(("end_interleave_boost\n"));
}



/*************************************
 *
 *  Compute the "perfect" interleave
 *  interval
 *
 *************************************/

static void compute_perfect_interleave(void)
{
	attoseconds_t smallest = attoseconds_per_cycle[0];
	int cpunum;

	/* start with a huge time factor and find the 2nd smallest cycle time */
	perfect_interleave = attotime_zero;
	perfect_interleave.attoseconds = ATTOSECONDS_PER_SECOND - 1;
	for (cpunum = 1; Machine->drv->cpu[cpunum].type != CPU_DUMMY; cpunum++)
	{
		/* find the 2nd smallest cycle interval */
		if (attoseconds_per_cycle[cpunum] < smallest)
		{
			perfect_interleave.attoseconds = smallest;
			smallest = attoseconds_per_cycle[cpunum];
		}
		else if (attoseconds_per_cycle[cpunum] < perfect_interleave.attoseconds)
			perfect_interleave.attoseconds = attoseconds_per_cycle[cpunum];
	}

	/* adjust the final value */
	if (perfect_interleave.attoseconds == ATTOSECONDS_PER_SECOND - 1)
		perfect_interleave.attoseconds = attoseconds_per_cycle[0];

	LOG(("Perfect interleave = %s, smallest = %.9f\n", attotime_string(perfect_interleave, 9), ATTOSECONDS_TO_DOUBLE(smallest)));
}



/*************************************
 *
 *  Setup all the core timers
 *
 *************************************/

static void cpu_inittimers(running_machine *machine)
{
	attotime first_time;
	int cpunum, max, ipf;

	/* allocate a dummy timer at the minimum frequency to break things up */
	ipf = machine->drv->cpu_slices_per_frame;
	if (ipf <= 0)
		ipf = 1;
	timeslice_period = attotime_make(0, machine->screen[0].refresh / ipf);
	timeslice_timer = timer_alloc(cpu_timeslicecallback, NULL);
	timer_adjust(timeslice_timer, timeslice_period, 0, timeslice_period);

	/* allocate timers to handle interleave boosts */
	interleave_boost_timer = timer_alloc(NULL, NULL);
	interleave_boost_timer_end = timer_alloc(end_interleave_boost, NULL);

	/*
     *  The following code finds all the CPUs that are interrupting in sync with the VBLANK
     *  and sets up the VBLANK timer to run at the minimum number of cycles per frame in
     *  order to service all the synced interrupts
     */

	/* find the CPU with the maximum interrupts per frame */
	max = 1;
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
	{
		ipf = machine->drv->cpu[cpunum].vblank_interrupts_per_frame;
		if (ipf > max)
			max = ipf;
	}

	/* now find the LCD with the rest of the CPUs (brute force - these numbers aren't huge) */
	vblank_multiplier = max;
	while (1)
	{
		for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
		{
			ipf = machine->drv->cpu[cpunum].vblank_interrupts_per_frame;
			if (ipf > 0 && (vblank_multiplier % ipf) != 0)
				break;
		}
		if (cpunum == cpu_gettotalcpu())
			break;
		vblank_multiplier += max;
	}

	/* initialize the countdown timers and intervals */
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
	{
		ipf = machine->drv->cpu[cpunum].vblank_interrupts_per_frame;
		if (ipf > 0)
			cpu[cpunum].vblankint_countdown = cpu[cpunum].vblankint_multiplier = vblank_multiplier / ipf;
		else
			cpu[cpunum].vblankint_countdown = cpu[cpunum].vblankint_multiplier = -1;
	}

	/* allocate a vblank timer at the frame rate * the LCD number of interrupts per frame */
	vblank_period = attotime_make(0, machine->screen[0].refresh / vblank_multiplier);
	vblank_countdown = vblank_multiplier;

	/* allocate an update timer that will be used to time the actual screen updates */
	update_timer = timer_alloc(cpu_updatecallback, NULL);

	/*
     *      The following code creates individual timers for each CPU whose interrupts are not
     *      synced to the VBLANK, and computes the typical number of cycles per interrupt
     */

	/* start the CPU interrupt timers */
	for (cpunum = 0; cpunum < cpu_gettotalcpu(); cpunum++)
	{
		ipf = machine->drv->cpu[cpunum].vblank_interrupts_per_frame;

		/* compute the average number of cycles per interrupt */
		if (ipf <= 0)
			ipf = 1;
		cpu[cpunum].vblankint_timer = timer_alloc(NULL, NULL);

		/* see if we need to allocate a CPU timer */
		if (machine->drv->cpu[cpunum].timed_interrupt_period != 0)
		{
			cpu[cpunum].timedint_period = attotime_make(0, machine->drv->cpu[cpunum].timed_interrupt_period);
			cpu[cpunum].timedint_timer = timer_alloc(cpu_timedintcallback, NULL);
			timer_adjust(cpu[cpunum].timedint_timer, cpu[cpunum].timedint_period, cpunum, cpu[cpunum].timedint_period);
		}
	}

	/* note that since we start the first frame on the refresh, we can't pulse starting
       immediately; instead, we back up one VBLANK period, and inch forward until we hit
       positive time. That time will be the time of the first VBLANK timer callback */
	first_time = attotime_sub_attoseconds(vblank_period, machine->screen[0].vblank);
	while (attotime_compare(first_time, attotime_zero) < 0)
	{
		cpu_vblankcallback(machine, NULL, -1);
		first_time = attotime_add(first_time, vblank_period);
	}
	timer_set(first_time, NULL, 0, cpu_firstvblankcallback);

	/* reset the refresh timer to get ourself back in sync */
	timer_adjust(refresh_timer, attotime_never, 0, attotime_never);
}