#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"io.h"

#include	"ureg.h"

void
delay(int ms)
{
	int i;

	ms *= 7000;		/* experimentally determined */
	for(i=0; i<ms; i++)
		;
}

/*
 * AMD 82C54 timer
 *
 * ctr2 is clocked at 3.6864 MHz. ctr2 output clocks ctr0 and ctr1.
 * ctr0 drives INTR2.  ctr1 drives INTR4.
 * To get 100Hz, 36864==9*4096=36*1024 so clock ctr2
 * every 1024 and ctr0 every 36.
 */

struct Timer{
	uchar	cnt0,
		junk0[3];
	uchar	cnt1,
		junk1[3];
	uchar	cnt2,
		junk2[3];
	uchar	ctl,
		junk3[3];
};


#define	TIME0	(36*MS2HZ/10)
#define	TIME1	0xFFFFFFFF	/* profiling disabled */
#define	TIME2	1024
#define	CTR(x)	((x)<<6)	/* which counter x */
#define	SET16	0x30		/* lsbyte then msbyte */
#define	MODE2	0x04		/* interval timer */

void
clockinit(void)
{
	Timer *t;
	int i;

	t = TIMERREG;
	t->ctl = CTR(2)|SET16|MODE2;
	t->cnt2 = TIME2&0xFF;
	t->cnt2 = (TIME2>>8)&0xFF;
	t->ctl = CTR(1)|SET16|MODE2;
	t->cnt1 = TIME1&0xFF;
	t->cnt1 = (TIME1>>8)&0xFF;
	t->ctl = CTR(0)|SET16|MODE2;
	t->cnt0 = TIME0;
	t->cnt0 = (TIME0>>8)&0xFF;
	i = *CLRTIM0;
	USED(i);
	i = *CLRTIM1;
	USED(i);
	m->ticks = 0;
}

void
clock(Ureg *ur)
{
	int i;

	if((ur->cause&INTR2) == 0) {
		if(ur->cause & INTR4) {
			i = *CLRTIM1;
			USED(i);
		}
		return;
	}
	nrun = 0;
	i = *CLRTIM0;
	USED(i);

	m->ticks++;
	if(m->proc)
		m->proc->pc = ur->pc;

	accounttime();
	duartslave();
	if((active.machs&(1<<m->machno)) == 0)
		return;

	if(active.exiting && active.machs&(1<<m->machno)) {
		print("someone's exiting\n");
		exit(0);
	}

	checkalarms();
	kproftimer(ur->pc);

	if(up == 0 || (ur->status&IEP) == 0 || up->state != Running)
		return;

	if(anyready())
		sched();

	/* user profiling clock */
	if(ur->status & KUP)
		(*(ulong*)(USTKTOP-BY2WD)) += TK2MS(1);	
}