diff options
Diffstat (limited to '')
-rw-r--r-- | c/build-tools/os/msdos/fixtimer.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/c/build-tools/os/msdos/fixtimer.c b/c/build-tools/os/msdos/fixtimer.c new file mode 100644 index 0000000000..3b71032550 --- /dev/null +++ b/c/build-tools/os/msdos/fixtimer.c @@ -0,0 +1,111 @@ +/* + * $Id$ + */ + +#include <stdio.h> +#include <dos.h> + +#define IO_RTC 0x70 /* RTC */ + +#define RTC_SEC 0x00 /* seconds */ +#define RTC_MIN 0x02 /* minutes */ +#define RTC_HRS 0x04 /* hours */ +#define RTC_WDAY 0x06 /* week day */ +#define RTC_DAY 0x07 /* day of month */ +#define RTC_MONTH 0x08 /* month of year */ +#define RTC_YEAR 0x09 /* month of year */ +#define RTC_STATUSA 0x0a /* status register A */ +#define RTCSA_TUP 0x80 /* time update, don't look now */ + +#define RTC_STATUSB 0x0b /* status register B */ + +#define RTC_DIAG 0x0e /* status register E - bios diagnostic */ +#define RTCDG_BITS "\020\010clock_battery\007ROM_cksum\006config_unit\005memory_size\004fixed_disk\003invalid_time" + + + +/* convert 2 digit BCD number */ +static int bcd( unsigned int i ) +{ + return ((i/16)*10 + (i%16)); +} + +static unsigned int rtcin( unsigned int what ) +{ + outportb( IO_RTC, what ); + return inportb( IO_RTC+1 ); +} + + +void fix_date( void ) +{ + int s; + struct date date; + struct time time; + + /* initialize brain-dead battery powered clock */ + outportb( IO_RTC, RTC_STATUSA ); + outportb( IO_RTC+1, 0x26 ); + outportb( IO_RTC, RTC_STATUSB ); + outportb( IO_RTC+1, 2 ); + + outportb( IO_RTC, RTC_DIAG ); + s = inportb( IO_RTC+1 ); + if (s) printf("RTC BIOS diagnostic error %b\n", s, RTCDG_BITS); + + /* check for presence of clock */ + s = rtcin(RTC_STATUSA); + if ( s == 0xff || s == 0 ) { + printf( "Real-time clock not found\n" ); + return; + } + + /* ready for a read? */ + while ((s & RTCSA_TUP) == RTCSA_TUP) + s = rtcin(RTC_STATUSA); + + date.da_year = bcd(rtcin(RTC_YEAR)) + 1900; /* year */ + if ( date.da_year < 1970) date.da_year += 100; + date.da_year -= 1980; + date.da_mon = bcd(rtcin(RTC_MONTH)); /* month */ + date.da_day = bcd(rtcin(RTC_DAY)); /* day */ + + (void)bcd(rtcin(RTC_WDAY)); /* weekday */ + + time.ti_hour = bcd(rtcin(RTC_HRS)); /* hour */ + time.ti_min = bcd(rtcin(RTC_MIN)); /* minutes */ + time.ti_sec = bcd(rtcin(RTC_SEC)); /* seconds */ + time.ti_hund = 0; + + setdate( & date ); + settime( & time ); +} + + + + +void fix_timer( void ) +{ +#define PIT_PORT 0x40 +#define TIMER_CNTR0 (PIT_PORT + 0) /* timer 0 counter port */ +#define TIMER_MODE (PIT_PORT + 3) /* timer mode port */ +#define TIMER_SEL0 0x00 /* select counter 0 */ +#define TIMER_RATEGEN 0x04 /* mode 2, rate generator */ +#define TIMER_16BIT 0x30 /* r/w counter 16 bits, LSB first */ + + /* set timer 0 to generate interrupts every period */ + outportb( TIMER_MODE, TIMER_SEL0|TIMER_RATEGEN|TIMER_16BIT ); + outportb( TIMER_CNTR0, 0 ); /* counter low */ + outportb( TIMER_CNTR0, 0 ); /* counter high */ +} + +int main(void) +{ + /* Make timer count at correct pace */ + fix_timer(); + + /* Fix the date */ + fix_date(); + + return 0; +} |