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/***********************************************************************
*
* Name: sys_sppt.c
*
* Purpose: Support Routines for Modules 3 and 4 of MPX-PC
*
* Sample Call:
* sys_init()
* sys_exit()
*
* Procedures In Module:
* sys_init - Sets up interrupt vector 60 for MPX-PC
* sys_exit - Resets interrupt vector 60 and exits to DOS
*
*
****************************************************************************/
#include <stdio.h>
#include <dos.h>
#include "mpx.h"
void interrupt (*vect60)(); /* Storage for DOS int 60h */
/* interrupt vector. */
void interrupt (*vect08)(); /* Storage for DOS int 08h */
/* interrupt vector. */
unsigned long clock; /* The clock counter */
void sys_init()
{
/* set up interrupt vector for MPX sys_calls */
vect60 = getvect(0x60);
setvect(0x60,&sys_call);
// set up the clock
clock_open();
}
void sys_exit()
{
// restore the clock
clock_close();
/* restore interrupt vector 60 and exit */
setvect(0x60,vect60);
exit();
}
void interrupt dispatch()
{
/* MOD 4 dispatch */
do {
cop = cop -> next;
} while (cop != NULL && cop->suspend == SUSPENDED);
if (cop == NULL) {
_SP = sp_save;
} else {
_SP = cop -> stack_ptr;
}
}
void interrupt sys_call()
{
struct parm {
int op_number;
int op_type;
char *buffer;
int *length;
};
static struct parm *parm_add;
/* Save stack pointer for current process */
cop->stack_ptr = _SP;
/* Get address of sys_call parameters */
parm_add = _SP + 0x1c; // parameter offset = 0x1C
/* Note that you should save this parameter address
somewhere in the pcb as suggested below*/
cop->parm_add = parm_add;
// find out if the process wants to die... and kill it
if (parm_add->op_number == EXIT_CODE) {
cop->suspend = SUSPENDED;
}
dispatch();
}
/*
* 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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