1994/0810/pc/clock.c (diff list | history)

pc/clock.c on 1991/0704
1991/0704		#include "u.h"
1992/0321		#include "../port/lib.h"
1991/0704		#include "mem.h" #include "dat.h" #include "fns.h" #include "io.h"
1991/0706		#include "ureg.h"
1991/0704
1991/0705		/* * 8253 timer */ enum {
1991/0709		T0cntr= 0x40, /* counter ports */ T1cntr= 0x41, /* ... */ T2cntr= 0x42, /* ... */ Tmode= 0x43, /* mode port */
1991/0705
1992/0923		/* commands */ Latch0= 0x00, /* latch counter 0's value */ Load0= 0x30, /* load counter 0 with 2 bytes */ /* modes */ Square= 0x36, /* perioic square wave */
1994/0512		Trigger= 0x30, /* interrupt on terminal count */
1992/0923		Freq= 1193182, /* Real clock frequency */
1991/0705		};
1994/0809		static int cpufreq = 66000000; static int cpumhz = 66;
1994/0716		static int cputype = 486; static int loopconst = 100;
1992/0923
1993/1124		static void clock(Ureg *ur, void *arg) { Proc *p; int nrun = 0; USED(arg); m->ticks++; checkalarms();
1994/0128		hardclock();
1994/0715		uartclock();
1993/1124		/* * process time accounting */ p = m->proc; if(p){ nrun = 1; p->pc = ur->pc; if (p->state==Running) p->time[p->insyscall]++; } nrun = (nrdy+nrun)*1000; MACHP(0)->load = (MACHP(0)->load*19+nrun)/20;
1994/0809		if(up && up->state == Running){
1994/0507		if(anyready()) sched(); /* user profiling clock */
1994/0810		if((ur->cs&0xffff) == UESEL)
1994/0809		(*(ulong*)(USTKTOP-BY2WD)) += TK2MS(1);
1994/0507		}
1993/1124
1994/0525		mouseclock();
1993/1124		}
1994/0302		/*
1994/0716		* delay for l milliseconds more or less. delayloop is set by * clockinit() to match the actual CPU speed.
1994/0302		*/
1994/0716		void delay(int l)
1994/0302		{
1994/0716		aamloop(l*loopconst); }
1994/0302		void printcpufreq(void) {
1994/0809		print("CPU is a %ud MHz (%ud Hz) %d\n", cpumhz, cpufreq, cputype);
1994/0302		}
1991/0704		void clockinit(void) {
1992/0923		ulong x, y; /* change in counter */
1994/0716		ulong cycles, loops;
1992/0922
1994/0809		switch(cputype = x86()){ case 386: loops = 10000; cycles = 32; break; case 486: loops = 10000; cycles = 22; break; default: loops = 30000; cycles = 23; break; }
1991/0709		/* * set vector for clock interrupts */
1993/1124		setvec(Clockvec, clock, 0);
1991/0709		/*
1994/0512		* set clock for 1/HZ seconds
1991/0709		*/
1994/0603		outb(Tmode, Load0|Square);
1991/0709		outb(T0cntr, (Freq/HZ)); /* low byte */ outb(T0cntr, (Freq/HZ)>>8); /* high byte */
1992/0922
1994/0809
1992/0922		/*
1994/0716		* measure time for the loop * * MOVL loops,CX * aaml1: AAM * LOOP aaml1 * * the time for the loop should be independent from external * cache's and memory system since it fits in the execution * prefetch buffer. *
1992/0922		*/ outb(Tmode, Latch0);
1992/0923		x = inb(T0cntr); x |= inb(T0cntr)<<8;
1994/0716		aamloop(loops);
1992/0923		outb(Tmode, Latch0); y = inb(T0cntr); y |= inb(T0cntr)<<8; x -= y; /*
1994/0716		* counter goes at twice the frequency, once per transition,
1994/0809		* i.e., twice per square wave
1992/0923		*/
1994/0716		x >>= 1; /* * figure out clock frequency and a loop multiplier for delay(). */
1994/0717		cpufreq = loops*((cycles*Freq)/x);
1994/0716		loopconst = (cpufreq/1000)/cycles; /* AAM+LOOP's for 1 ms */
1994/0719
1994/0809		/* * add in possible .1% error and convert to MHz */ cpumhz = (cpufreq + cpufreq/1000)/1000000;
1991/0808		}