Create cmos.c

2026-02-11 21:35:20 -08:00 · 2026-01-28 16:58:08 -08:00
parent e750049556
commit 05f5576c9c
1 changed files with 86 additions and 0 deletions
--- a/kernel/cmos.c
+++ b/kernel/cmos.c
@@ -0,0 +1,86 @@
+#include "cmos.h"
+#include "io.h"
+#include "print.h"
+
+#define CMOS_ADDR 0x70
+#define CMOS_DATA 0x71
+
+enum {
+    CMOS_SEC  = 0x00,
+    CMOS_MIN  = 0x02,
+    CMOS_HOUR = 0x04,
+    CMOS_DAY  = 0x07,
+    CMOS_MONTH= 0x08,
+    CMOS_YEAR = 0x09,
+    CMOS_STAT_A = 0x0A,
+    CMOS_STAT_B = 0x0B
+};
+
+// Check if CMOS is currently updating its values
+static int is_updating() {
+    outb(CMOS_ADDR, CMOS_STAT_A);
+    return (inb(CMOS_DATA) & 0x80);
+}
+
+static uint8_t get_register(int reg) {
+    outb(CMOS_ADDR, reg);
+    return inb(CMOS_DATA);
+}
+
+void cmos_read_time(cmos_time_t* time) {
+    // Wait for any current update to finish
+    while (is_updating());
+
+    uint8_t sec   = get_register(CMOS_SEC);
+    uint8_t min   = get_register(CMOS_MIN);
+    uint8_t hour  = get_register(CMOS_HOUR);
+    uint8_t day   = get_register(CMOS_DAY);
+    uint8_t month = get_register(CMOS_MONTH);
+    uint8_t year  = get_register(CMOS_YEAR);
+    uint8_t statb = get_register(CMOS_STAT_B);
+
+    // If Bit 2 of Status Register B is 0, then values are BCD
+    if (!(statb & 0x04)) {
+        time->second = (sec & 0x0F) + ((sec / 16) * 10);
+        time->minute = (min & 0x0F) + ((min / 16) * 10);
+        time->hour   = ((hour & 0x0F) + (((hour & 0x70) / 16) * 10)) | (hour & 0x80);
+        time->day    = (day & 0x0F) + ((day / 16) * 10);
+        time->month  = (month & 0x0F) + ((month / 16) * 10);
+        time->year   = (year & 0x0F) + ((year / 16) * 10);
+    } else {
+        time->second = sec;
+        time->minute = min;
+        time->hour   = hour;
+        time->day    = day;
+        time->month  = month;
+        time->year   = year;
+    }
+
+    // Adjust for Century (assuming we are in the 2000s for ClassicOS)
+    time->year += 2000; 
+}
+
+void cmos_print_time(cmos_time_t* time) {
+    // Using your print_string/itoa style logic
+    char buf[16];
+    
+    print_string("System Time: ");
+    
+    // Simple padding check for minutes
+    print_hex(time->hour, 0, 1);
+    print_string(":");
+    if (time->minute < 10) print_string("0");
+    print_hex(time->minute, 0, 1);
+    print_string(":");
+    if (time->second < 10) print_string("0");
+    print_hex(time->second, 0, 1);
+    
+    print_string("  ");
+    
+    print_hex(time->month, 0, 1);
+    print_string("/");
+    print_hex(time->day, 0, 1);
+    print_string("/");
+    print_hex(time->year, 0, 1);
+    print_string("\n");
+}