/*	program in MIX 'C' to set real-time-clock located at ports
	30h through 33h in Morrow MD 2/3 rev. 2 main board.
		Mike Allen   8/10/86				*/

#include "stdio"
#include "stdlib.h"

#define	CLS	'Z'-0x40	/* Clear Screen (^Z) */
#define PA	0x30		/* 8255 A register */
#define	PB	0x31		/* 8255 B register */
#define	PC	0x32		/* 8255 C register */
#define CNTRL	0x33		/* 8255 Control register */

main()

{
	int	rtc[13];	/* MSM8532 registers */
	
	int	i,		/* general loop variable */
		civil_time,	/* 24hr, AM or PM indicator */
		new_in;		/* new values */

	char junque[3];		/* input string */

	putchar(CLS);			/* Clear the screen */
	outp(CNTRL,'\220');		/* Set up 8255 */
	outp(PC,'\040');		/* Put MSM5832 in 'read' mode */
	for(i=2;i<13;i++) {	/* read top 11 MSM5832 registers */
		outp(PB,i);	/* output the register address */
		rtc[i]=inp(PA)&0xf;	/* read the register and
					   strip the 4 top bits */
	}
	outp(PC,'\000');	/* Take the MSM5832 out of the read mode */
	if(rtc[5]>7)		/* check for 24 hr time. */
		civil_time=0;
	else if(rtc[5]>3)	/* not 24 hr,  check for PM */
		civil_time=2;
	else 			/* not 24 hr or PM.  Must be AM. */
		civil_time=1;
	do {
		new_in = 10*rtc[12]+rtc[11];	/* old value of years */
		printf("Year? <%d> ",new_in);	/* show it */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);	/* if so, make integer */
	} while( new_in < 0 || new_in > 99);	/* make sure it's valid */
	rtc[12] = new_in/10;			/* set up 10s of years */
	rtc[11] = new_in%10;			/* set up 1s of years */
	do {
		new_in = rtc[8]/4;		/* old leap year flag */
		printf("Leap year? [1=yes] <%d> ",new_in);	/* show it */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);	/* if so, make integer */
	} while( new_in < 0 || new_in > 1);	/* make sure it's valid */
	rtc[8] = (rtc[8] & 0x3) | (new_in*4);	/* set/reset leap year flag */
	do {
		new_in = 10*rtc[10]+rtc[9];	/* old value of month */
		printf("Month? <%d> ",new_in);	/* show it */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);	/* if so, make integer */
	} while( new_in < 1 || new_in > 12);	/* make sure it's valid */
	rtc[10] = new_in/10;			/* set up 10s of months */
	rtc[9] = new_in%10;			/* set up 1s of months */
	do {
		new_in = 10*(rtc[8] & 0x3)+rtc[7];
						/* old value of day */
		printf("Day? <%d> ",new_in);	/* show it */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);	/* if so, make integer */
	} while( new_in < 1 || new_in > 31);	/* make sure it's valid */
	rtc[8] = (rtc[8] & 0x4) | (new_in/10);	/* set up 10s of days */
	rtc[7] = new_in%10;			/* set up 1s of years */
	do {
		new_in = rtc[6];	/* old value of day of week */
		printf("Day of week? [0=Sunday, 6=Saturday] <%d> ",new_in);
						/* show it */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);	/* if so, make integer */
	} while( new_in < 0 || new_in > 6);	/* make sure it's valid */
	rtc[6] = new_in;			/* set up day of week */
	do {
		new_in = civil_time;
		printf("24 hr[0], AM[1] or PM[2]? <%d> ",new_in);
						/* show 24hr, AM, PM flags */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);
						/* if so, make integer */
	} while( new_in < 0 || new_in > 2);
						/* make sure it's valid */
	civil_time = new_in;
	new_in = 10*(rtc[5] & 0x3) + rtc[4];	/* get hours */
	rtc[5] = rtc[5] & 0x3;			/* clear 24hr & PM flags */
	switch(civil_time) {
		case 0:	rtc[5] |= 0x8;		/* set 24hr flag */
			break;
		case 2:	rtc[5] |= 0x4;		/* set PM flag */
			break;
		default:	break;
	}
	if (civil_time) {		/* make sure 12hr times are valid */
		if (new_in > 12)
			new_in -=12;
		else if (new_in == 0)
			new_in = 12;
		rtc[5] = (rtc[5] & 0x4) | (new_in/10);	/* set 10s of hours */
		rtc[4] = new_in%10;			/* set 1s of hours */
		do {
			new_in = 10*(rtc[5] & 0x3)+rtc[4];	
						/* old value of hours */
			printf("Hours? <%d> ",new_in);	/* show it */
			gets(junque);			/* get input */
			if (strlen(junque))		/* see if new value */
				new_in = atoi(junque);
						/* if so, make integer */
		} while( new_in < 1 || new_in > 12);
						/* make sure it's valid */
	}
	else {
		do {
			new_in = 10*(rtc[5] & 0x3)+rtc[4];	
						/* old value of hours */
			printf("Hours? <%d> ",new_in);	/* show it */
			gets(junque);			/* get input */
			if (strlen(junque))		/* see if new value */
				new_in = atoi(junque);
						/* if so, make integer */
		} while( new_in < 0 || new_in > 23);
						/* make sure it's valid */
	}
	rtc[5] = (rtc[5] & 0xC) | (new_in/10);	/* set up 10s of hours */
	rtc[4] = new_in%10;			/* set up 1s of hours */
	do {
		new_in = 10*rtc[3]+rtc[2];	/* old value of minutes */
		printf("Minutes? <%d> ",new_in);	/* show it */
		gets(junque);			/* get input */
		if (strlen(junque))		/* see if new value */
			new_in = atoi(junque);	/* if so, make integer */
	} while( new_in < 0 || new_in > 59);	/* make sure it's valid */
	rtc[3] = new_in/10;			/* set up 10s of minutes */
	rtc[2] = new_in%10;			/* set up 1s of minutes */
	puts("Press RETURN to start clock on the minute.");
						/* prompt user */
	gets(junque);				/* load the clock */
	outp(CNTRL,'\200');			/* set up 8255 */
	outp(PC,'\020');			/* turn on the hold */
	for(i=0;i<15;i++);			/* wait a LONG time */
	for(i=0;i<13;i++) {		/* write ALL 13 MSM5832 registers
					   to reset seconds */
		outp(PB,i);		/* output the register address */
		outp(PA,(rtc[i] & 0xF));	/* output the bottom 4 bits
							of the register */
		outp(PC,'\120');	/* strobe the write line */
		outp(PC,'\020');
	}
	outp(PC,'\000');		/* trun off the hold line */
	outp(CNTRL,'\220');		/* restore the 8255 */
	exit(0);		/* We done! We bad! */
}