1994/1031/pc/clock.c (diff list | history)

1994/1029/sys/src/9/pc/clock.c:29,37 – 1994/1031/sys/src/9/pc/clock.c:29,36 (short | long | prev | next)
add x86type table to determine proper cycles multiplier for AAM loop. determine loops value dynamically to get long sample. rsc Fri Mar 4 12:44:25 2005
1991/0705
1994/0809		static int cpufreq = 66000000; static int cpumhz = 66;
1994/0716		static int cputype = 486; static int loopconst = 100;
1994/1029		ulong cpuidax, cpuiddx;
1994/1031		static int cpuidax, cpuiddx;
1992/0923
1993/1124		static void clock(Ureg *ur, void *arg)
1994/1029/sys/src/9/pc/clock.c:72,77 – 1994/1031/sys/src/9/pc/clock.c:71,119
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 */ { 4, 0, 22, "Intel486DX", }, { 4, 1, 22, "Intel486DX", }, { 4, 2, 22, "Intel486SX", }, { 4, 4, 22, "Intel486DX2", }, { 4, 5, 22, "Intel486SL", }, { 4, 8, 22, "IntelDX4", }, { 5, 1, 23, "Pentium510", }, { 5, 2, 23, "Pentium735", }, /* family defaults */ { 3, -1, 32, "Intel386", }, { 4, -1, 22, "Intel486", }, { 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.
1994/1029/sys/src/9/pc/clock.c:89,115 – 1994/1031/sys/src/9/pc/clock.c:131,149
1994/1029		cpufreq, cputype, cpuidax, cpuiddx);
1994/0302		}
1994/1031		int x86(void) { return cputype->family; }
1991/0704		void clockinit(void) {
1992/0923		ulong x, y; /* change in counter */
1994/0716		ulong cycles, loops;
1994/1031		int x, y; /* change in counter */ int family, model, loops; X86type *t;
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 */
1994/1029/sys/src/9/pc/clock.c:116,121 – 1994/1031/sys/src/9/pc/clock.c:150,168
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);
1994/1029/sys/src/9/pc/clock.c:122,160 – 1994/1031/sys/src/9/pc/clock.c:169,214
1991/0709		outb(T0cntr, (Freq/HZ)); /* low byte */ outb(T0cntr, (Freq/HZ)>>8); /* high byte */
1992/0922
1994/1031		/* use biggest loop that works */ for(loops = 10000; ; loops += 5000) { /* * 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;
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;
1994/1031		if(x < 0) x += 2^16; if(x > (2^15)) break; /* * counter goes at twice the frequency, once per transition, * i.e., twice per square wave */ x >>= 1;
1992/0923		/*
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 */
1994/1031		/* * 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 */ } while(x > 0);
1994/0719
1994/0809		/* * add in possible .1% error and convert to MHz