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src/kernel --> src/

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boreddevnl
2026-03-16 00:30:47 +01:00
parent 3da1496e4f
commit fc83d7941b
630 changed files with 2 additions and 2 deletions
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113
src/dev/rtc.c Normal file
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// Copyright (c) 2023-2026 Chris (boreddevnl)
// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
// This header needs to maintain in any file it is present in, as per the GPL license terms.
#include "rtc.h"
#include "io.h"
#define CMOS_ADDRESS 0x70
#define CMOS_DATA 0x71
static int updating_rtc() {
outb(CMOS_ADDRESS, 0x0A);
return (inb(CMOS_DATA) & 0x80);
}
static uint8_t get_rtc_register(int reg) {
outb(CMOS_ADDRESS, reg);
return inb(CMOS_DATA);
}
void rtc_get_datetime(int *year, int *month, int *day, int *hour, int *minute, int *second) {
uint8_t century;
uint8_t last_second;
uint8_t last_minute;
uint8_t last_hour;
uint8_t last_day;
uint8_t last_month;
uint8_t last_year;
uint8_t last_century;
uint8_t registerB;
while (updating_rtc());
*second = get_rtc_register(0x00);
*minute = get_rtc_register(0x02);
*hour = get_rtc_register(0x04);
*day = get_rtc_register(0x07);
*month = get_rtc_register(0x08);
*year = get_rtc_register(0x09);
do {
last_second = *second;
last_minute = *minute;
last_hour = *hour;
last_day = *day;
last_month = *month;
last_year = *year;
while (updating_rtc());
*second = get_rtc_register(0x00);
*minute = get_rtc_register(0x02);
*hour = get_rtc_register(0x04);
*day = get_rtc_register(0x07);
*month = get_rtc_register(0x08);
*year = get_rtc_register(0x09);
} while( (last_second != *second) || (last_minute != *minute) || (last_hour != *hour) ||
(last_day != *day) || (last_month != *month) || (last_year != *year) );
registerB = get_rtc_register(0x0B);
// Convert BCD to binary values if necessary
if (!(registerB & 0x04)) {
*second = (*second & 0x0F) + ((*second / 16) * 10);
*minute = (*minute & 0x0F) + ((*minute / 16) * 10);
*hour = ( (*hour & 0x0F) + (((*hour & 0x70) / 16) * 10) ) | (*hour & 0x80);
*day = (*day & 0x0F) + ((*day / 16) * 10);
*month = (*month & 0x0F) + ((*month / 16) * 10);
*year = (*year & 0x0F) + ((*year / 16) * 10);
}
// Convert 12 hour clock to 24 hour clock if necessary
if (!(registerB & 0x02) && (*hour & 0x80)) {
*hour = ((*hour & 0x7F) + 12) % 24;
}
// Calculate full year
*year += 2000;
}
static void set_rtc_register(int reg, uint8_t value) {
outb(CMOS_ADDRESS, reg);
outb(CMOS_DATA, value);
}
void rtc_set_datetime(int year, int month, int day, int hour, int minute, int second) {
uint8_t registerB = get_rtc_register(0x0B);
// Disable NMI and start update
outb(CMOS_ADDRESS, 0x8B);
uint8_t prev_b = inb(CMOS_DATA);
outb(CMOS_DATA, prev_b | 0x80); // Set SET bit to prevent updates while writing
if (year >= 2000) year -= 2000;
if (!(registerB & 0x04)) {
// Convert binary to BCD
second = ((second / 10) << 4) | (second % 10);
minute = ((minute / 10) << 4) | (minute % 10);
hour = ((hour / 10) << 4) | (hour % 10);
day = ((day / 10) << 4) | (day % 10);
month = ((month / 10) << 4) | (month % 10);
year = ((year / 10) << 4) | (year % 10);
}
set_rtc_register(0x00, (uint8_t)second);
set_rtc_register(0x02, (uint8_t)minute);
set_rtc_register(0x04, (uint8_t)hour);
set_rtc_register(0x07, (uint8_t)day);
set_rtc_register(0x08, (uint8_t)month);
set_rtc_register(0x09, (uint8_t)year);
// Re-enable updates
outb(CMOS_ADDRESS, 0x8B);
outb(CMOS_DATA, prev_b & ~0x80);
}