/* These routines, plus the assembler hooks in stopwatch.asm, implement a
 * general purpose "stopwatch" facility useful for timing the execution of
 * code segments. The PC's "timer 2" channel (the one ordinarily
 * used to drive the speaker) is used. It is driven with a 838 ns
 * clock. The timer is 16 bits wide, so it "wraps around" in only 55 ms.
 *
 * There is an array of "stopwatch" structures used for recording the number
 * of uses and the min/max times for each. Since only one hardware timer is
 * available, only one stopwatch can actually be running at any one time.
 *
 * This facility is useful mainly for timing routines that must execute with
 * interrupts disabled. An interrupt that occurs while the timer is running
 * will not stop it, so it would show an errneously large value.
 *
 * To start a timer, call swstart(). To stop it and record its value,
 * call swstop(n), where n is the number of the stopwatch structure.
 * The stopwatch structures can be displayed with the "watch" command.
 *
 * Copyright 1991 Phil Karn, KA9Q
 */

#include "global.h"
#include "pc.h"

struct stopwatch Sw[NSW];

/* Stop a stopwatch and record its value.
 * Uses stopval() routine in stopwatch.asm
 */
void
swstop(n)
int n;
{
	register int16 cnt;
	register struct stopwatch *sw;

	cnt = stopval();
	sw = &Sw[n];

	if(sw->calls++ == 0){
		sw->maxval = cnt;
		sw->minval = cnt;
	} else if(cnt > sw->maxval){
		sw->maxval = cnt;
	} else if(cnt < sw->minval){
		sw->minval = cnt;
	}
}
int
doswatch(argc,argv,p)
int argc;
char *argv[];
void *p;
{
	register struct stopwatch *sw;
	long maxval,minval;
	int i;

	if(argc > 1){
		/* Clear timers */
		for(i=0,sw=Sw;i < NSW;i++,sw++){
			sw->calls = 0;
		}
	}
	for(i=0,sw=Sw;sw < &Sw[NSW];i++,sw++){
		if(sw->calls != 0){
			minval = (65536 - sw->maxval) * 838 / 1000;
			maxval = (65536 - sw->minval) * 838 / 1000;
			tprintf("%d: calls %ld min %ld max %ld\n",
			 i,sw->calls,minval,maxval);
		}
	}
	return 0;
}