1994/1206/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 loopconst = 100;
1994/1031		static int cpuidax, cpuiddx;
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		}
1994/1031		#define STEPPING(x) ((x)&0xf) #define MODEL(x) (((x)>>4)&0xf) #define FAMILY(x) (((x)>>8)&0xf) enum { /* flags */ CpuidFPU = 0x001, /* on-chip floating point unit */ CpuidMCE = 0x080, /* machine check exception */ CpuidCX8 = 0x100, /* CMPXCHG8B instruction */ }; typedef struct { int family; int model; int aalcycles; char *name; } X86type; X86type x86type[] = { /* from the cpuid instruction */
1994/1120		{ 4, 0, 22, "Intel486DX", }, { 4, 1, 22, "Intel486DX", }, { 4, 2, 22, "Intel486SX", }, { 4, 3, 22, "Intel486DX2", }, { 4, 4, 22, "Intel486DX2", }, { 4, 5, 22, "Intel486SL", }, { 4, 8, 22, "IntelDX4", },
1994/1031		{ 5, 1, 23, "Pentium510", }, { 5, 2, 23, "Pentium735", }, /* family defaults */ { 3, -1, 32, "Intel386", },
1994/1120		{ 4, -1, 22, "Intel486", },
1994/1031		{ 5, -1, 23, "Pentium", }, /* total default */ { -1, -1, 23, "unknown", }, }; static X86type *cputype;
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) {
1994/1101		print("CPU is a %d MHz %s (cpuid: ax %lux dx %lux)\n", cpumhz, cputype->name, cpuidax, cpuiddx);
1994/0302		}
1994/1031		int x86(void) { return cputype->family; }
1991/0704		void clockinit(void) {
1994/1031		int x, y; /* change in counter */
1994/1201		int family, model, loops, incr;
1994/1031		X86type *t;
1992/0922
1991/0709		/* * set vector for clock interrupts */
1993/1124		setvec(Clockvec, clock, 0);
1991/0709		/*
1994/1031		* figure out what we are */ x86cpuid(&cpuidax, &cpuiddx); family = FAMILY(cpuidax); model = MODEL(cpuidax); for(t = x86type; t->name; t++) if((t->family == family && t->model == model) || (t->family == family && t->model == -1) || (t->family == -1)) break; cputype = t; /*
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
1994/1201		/* find biggest loop that doesn't wrap */ incr = 16000000/(t->aalcycles*HZ*2);
1994/1206		x = 2000;
1994/1201		for(loops = incr; loops < 64*1024; loops += incr) { /* * measure time for the loop * * MOVL loops,CX * aaml1: AAM * LOOP aaml1 * * the time for the loop should be independent of external * cache and memory system since it fits in the execution * prefetch buffer. * */ outb(Tmode, Latch0); x = inb(T0cntr); x |= inb(T0cntr)<<8; aamloop(loops); outb(Tmode, Latch0); y = inb(T0cntr); y |= inb(T0cntr)<<8; x -= y; if(x < 0) x += Freq/HZ;
1994/0809
1994/1201		if(x > Freq/(3*HZ)) break; }
1992/0923
1994/1101		/* * counter goes at twice the frequency, once per transition, * i.e., twice per square wave */ x >>= 1; /* * figure out clock frequency and a loop multiplier for delay(). */ cpufreq = loops*((t->aalcycles*Freq)/x); loopconst = (cpufreq/1000)/t->aalcycles; /* AAM+LOOP's for 1 ms */
1994/0719
1994/0809		/*
1994/1201		* add in possible .2% error and convert to MHz
1994/0809		*/
1994/1201		cpumhz = (cpufreq + cpufreq/500)/1000000;
1991/0808		}