diff options
Diffstat (limited to 'src/kernel/cmos/rtc.c')
| -rw-r--r-- | src/kernel/cmos/rtc.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/src/kernel/cmos/rtc.c b/src/kernel/cmos/rtc.c new file mode 100644 index 0000000..ed7c494 --- /dev/null +++ b/src/kernel/cmos/rtc.c @@ -0,0 +1,99 @@ +#include <kernel/io/io.h> +#include <kernel/graphics/vesa.h> +#include <kernel/acpi/acpi.h> + +unsigned char second; +unsigned char minute; +unsigned char hour; +unsigned char day; +unsigned char month; +unsigned int year; + +int get_update_in_progress_flag() { + send_b(0x70, 0x0A); + return (receive_b(0x71) & 0x80); +} + +unsigned char get_rtc_register(int reg) { + send_b(0x70, reg); + return receive_b(0x71); +} + +void read_rtc() { + unsigned int century; + unsigned char last_second; + unsigned char last_minute; + unsigned char last_hour; + unsigned char last_day; + unsigned char last_month; + unsigned char last_year; + unsigned char last_century; + unsigned char registerB; + + while (get_update_in_progress_flag()); + 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); + century = get_rtc_register(facp->century); + + // Try until the values are the same (fix for RTC updates) + do { + last_second = second; + last_minute = minute; + last_hour = hour; + last_day = day; + last_month = month; + last_year = year; + last_century = century; + + while (get_update_in_progress_flag()); + 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); + century = get_rtc_register(facp->century); + } while ((last_second != second) || (last_minute != minute) || (last_hour != hour) || + (last_day != day) || (last_month != month) || (last_year != year) || + (last_century != century)); + + registerB = get_rtc_register(0x0B); + + 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); + century = (century & 0x0F) + ((century / 16) * 10); + } + + year += century * 100; + + // Convert to 24h if necessary + if (!(registerB & 0x02) && (hour & 0x80)) { + hour = ((hour & 0x7F) + 12) % 24; + } +} + +void write_time() { + read_rtc(); + vesa_draw_string("Current time: "); + vesa_draw_number(hour); + vesa_draw_string(":"); + vesa_draw_number(minute); + vesa_draw_string(":"); + vesa_draw_number(second); + vesa_draw_string(" "); + vesa_draw_number(month); + vesa_draw_string("/"); + vesa_draw_number(day); + vesa_draw_string("/"); + vesa_draw_number(year); + vesa_draw_string("\n"); +}
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