diff options
Diffstat (limited to 'clock.c')
| -rw-r--r-- | clock.c | 141 |
1 files changed, 141 insertions, 0 deletions
@@ -0,0 +1,141 @@ +/*
+ * Clock support for MPX-OS
+ * Ben Burwell & Averill Morash
+ * CSI350 - Fall 2013
+ */
+
+#include <dos.h>
+#include "mpx.h"
+
+void interrupt (*vect08)();
+unsigned long clock; /* The clock counter */
+
+/*
+ * Set up MXP clock
+ */
+void clock_open() {
+ unsigned char imr;
+
+ disable();
+ /* set up interrupt vector for timer interrupts */
+ vect08 = getvect(0x08);
+ setvect(0x08,&clock_int);
+
+ // set the timer mode
+ outportb(CMR, 0x36);
+ outportb(0x40, 0);
+ outportb(0x40, 0);
+
+ // set the count clock
+ clock = 0L;
+
+ // enable timer interrupts
+ imr = inportb(IMR); // Get current IMR
+ imr = imr & CLOCK_ENABLE; // Clear timer bit
+ outportb(IMR, imr); // Set new IMR
+
+ enable();
+}
+
+/*
+ * Restore the MS DOS clock
+ */
+void clock_close() {
+ disable();
+ setvect(0x08,vect08);
+ enable();
+}
+
+void interrupt clock_int() {
+ disable();
+ // if it's been 24 hours, reset clock to 0
+ if (clock >= 1572462L) {
+ clock = 0L;
+ } else {
+ clock++;
+ }
+ outportb(0x20, 0x20);
+ enable();
+}
+
+void stop_clock() {
+ unsigned char imr;
+ disable();
+
+ imr = inportb(IMR); // Get the old imr
+ imr = imr | CLOCK_DISABLE; // Disable timer interrupts
+ outportb(IMR, imr); // Set the new imr
+
+ enable();
+}
+
+/*
+ * Enables the timer interrupt
+ */
+void start_clock() {
+ unsigned char imr;
+ disable();
+
+ imr = inportb(IMR); // Get the old imr
+ imr = imr & CLOCK_ENABLE; // Enable timer interrupts
+ outportb(IMR, imr); // Set the new imr
+
+ enable();
+}
+
+/*
+ * Sets the value of the clock
+ */
+int set_clock(int hr, int m, int s) {
+ unsigned long ticks;
+
+ // Validate input
+ if (hr > 23 || hr < 0 || m > 59 || m < 0 || s > 59 || s < 0) {
+ return -1;
+ }
+
+ // set clock
+ ticks = 0L;
+ ticks = ((unsigned long)hr * 3600L * 91L / 5L);
+ ticks += ((unsigned long)m * 60L * 91L / 5L);
+ ticks += ((unsigned long)s * 91L / 5L);
+
+ disable();
+ clock = ticks;
+ enable();
+
+ return 0;
+}
+
+/*
+ * Gets the value of the clock
+ */
+void read_clock(int *hr, int *m, int *s) {
+ unsigned long ticks;
+ long total_seconds = 0L;
+ int l_hr = 0;
+ int l_m = 0; //local vars for hr, m
+
+ disable();
+ ticks = clock;
+ enable();
+
+ total_seconds = ticks * 10L;
+ total_seconds = total_seconds / 182L;
+
+ //count the whole hours
+ while (total_seconds >= 3600L) {
+ l_hr++;
+ total_seconds = total_seconds - 3600L;
+ }
+
+ //count the whole minutes
+ while (total_seconds >= 60L) {
+ l_m++;
+ total_seconds = total_seconds - 60L;
+ }
+
+ *hr = l_hr;
+ *m = l_m;
+ *s = total_seconds;
+}
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