clock.c

raywill写的操作系统内核

#include <maray/clock.h>
#include <libc.h>

/* What is BCD? Ref to man directory */
/* Generally speaking,use one byte to store two digits .Simple! */
#define BCD_TO_DEC(b) ( b = (b>>4)*10 + (b&15))/* Learn from Linux,really good :)*/
#define CMOS_READ(addr) ({	\
	outportb(0x70,addr);		\
	inportb(0x71);					\
})/* I don'tknow if '{}' are nessary.Just add it ,won't do any harm . */

extern sys_time real_tm;
extern sys_time start_tm;


void init_system_clock(sys_time *tm)
{
	/* 0x70 is the register address index port of RTC(Real Time)
		 0x71 is the data port
	*/
		do{
		tm->sec = CMOS_READ(0);
		tm->min =	CMOS_READ(2);
		tm->hour=	CMOS_READ(4);
		tm->day =	 CMOS_READ(7);
		tm->month= CMOS_READ(8);
		tm->year=	CMOS_READ(9);/*take care,year has only 2 bits*/
		tm->week=	CMOS_READ(6);
	}while(tm->sec!=CMOS_READ(0) );
	BCD_TO_DEC(tm->sec);
	BCD_TO_DEC(tm->min );
	BCD_TO_DEC(tm->hour);
	BCD_TO_DEC(tm->month);
	BCD_TO_DEC(tm->year);
	BCD_TO_DEC(tm->week);
	tm->week--;/* I prefer Sun=0,Mon=1,....,Sat=6 */
	tm->month++;
}

char *timetostr(sys_time *ptm,char *tstr)
{
	/*What if I have a own version of sprintf()! */
	char *sp=tstr;
	char buf[3];	
	/*Should look like 6-1-8 */
	/* I would like to regard it as UTC time system ,ranges from 1950-2049*/
	if(ptm->year < 10){
		 strcpy(sp,"200");
		}else{ 
			if(ptm->year < 50) 
				strcpy(sp,"20");
			else
				strcpy(sp,"19");
		}
		
		
	itoa(ptm->year,buf);
	strcat(sp,buf);
	strcat(sp,"-");
	itoa(ptm->month,buf);
	strcat(sp,buf);
	strcat(sp,"-");
	itoa(ptm->day,buf);
	strcat(sp,buf);

	strcat(sp,"  ");/*seperator*/

	/* now the time */				
	itoa(ptm->hour,buf);
	strcat(sp,buf);	
	strcat(sp,":");
	itoa(ptm->min,buf);
	strcat(sp,buf);
	strcat(sp,":");	
	itoa(ptm->sec,buf);
	strcat(sp,buf);


	return tstr;
}


sys_time *update_sys_time(int timefly)
{
	int sec=timefly*20/1000;
	
	int r_sec =  sec%60;
	int r_min = (sec - r_sec  )% 60;
	int r_hour= (sec - r_sec - r_min * 60 ) %60;
	real_tm.sec = start_tm.sec + r_sec ;
	if(real_tm.sec >= 60){
		real_tm.sec= real_tm.sec-60 ;
		real_tm.min++;
	}
	real_tm.min = start_tm.min + r_min;
	if(real_tm.min >= 60 ){
		real_tm.min= real_tm.min-60;
		real_tm.hour++;
	}
	real_tm.hour=start_tm.hour+r_hour;

	real_tm.day = start_tm.day;
	
	if(real_tm.hour>=24 ){
		real_tm.hour =  real_tm.hour - 24 ;
		real_tm.day++;
		/* And month ,but I don't want to deal with it now :( */
	}	
	real_tm.day = start_tm.day;
	real_tm.month = start_tm.month;
	real_tm.year = start_tm.year;
	real_tm.week = start_tm.week;
	return &real_tm;
}