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/*
* PC/HW routine collection v1.3 for DOS/DJGPP
*
* Copyright (C) 2002 - Borca Daniel
* Email : dborca@yahoo.com
* Web : http://www.geocities.com/dborca
*/
#include <pc.h>
#include "pc_hw.h"
#define TIMER_IRQ 0
#define MAX_TIMERS 8
#define PIT_FREQ 0x1234DD
#define unvolatile(__v, __t) __extension__ ({union { volatile __t __cp; __t __p; } __q; __q.__cp = __v; __q.__p;})
static int timer_installed;
typedef struct {
volatile unsigned int counter, clock_ticks, freq;
volatile PFUNC func;
volatile void *parm;
} TIMER;
static TIMER timer_main, timer_func[MAX_TIMERS];
static int timer ()
{
int i;
for (i=0;i<MAX_TIMERS;i++) {
TIMER *t = &timer_func[i];
if (t->func) {
t->clock_ticks += t->counter;
if (t->clock_ticks>=timer_main.counter) {
t->clock_ticks -= timer_main.counter;
t->func(unvolatile(t->parm, void *));
}
}
}
timer_main.clock_ticks += timer_main.counter;
if (timer_main.clock_ticks>=0x10000) {
timer_main.clock_ticks -= 0x10000;
return 1;
} else {
outportb(0x20, 0x20);
return 0;
}
} ENDOFUNC(timer)
void pc_remove_timer (void)
{
if (timer_installed) {
timer_installed = FALSE;
pc_clexit(pc_remove_timer);
DISABLE();
outportb(0x43, 0x34);
outportb(0x40, 0);
outportb(0x40, 0);
ENABLE();
pc_remove_irq(TIMER_IRQ);
}
}
static int install_timer (void)
{
if (timer_installed||pc_install_irq(TIMER_IRQ, timer)) {
return -1;
} else {
LOCKDATA(timer_func);
LOCKDATA(timer_main);
LOCKFUNC(timer);
timer_main.counter = 0x10000;
DISABLE();
outportb(0x43, 0x34);
outportb(0x40, 0);
outportb(0x40, 0);
timer_main.clock_ticks = 0;
ENABLE();
pc_atexit(pc_remove_timer);
timer_installed = TRUE;
return 0;
}
}
static TIMER *find_slot (PFUNC func)
{
int i;
for (i=0;i<MAX_TIMERS;i++) {
if (timer_func[i].func==func) {
return &timer_func[i];
}
}
for (i=0;i<MAX_TIMERS;i++) {
if (!timer_func[i].func) {
return &timer_func[i];
}
}
return NULL;
}
int pc_install_int (PFUNC func, void *parm, unsigned int freq)
{
int i;
TIMER *t;
if (!timer_installed) {
if (install_timer()) {
return -1;
}
}
if ((t=find_slot(func))!=NULL) {
unsigned int new_counter = PIT_FREQ / freq;
DISABLE();
t->func = func;
t->parm = parm;
t->freq = freq;
t->clock_ticks = 0;
if (new_counter < timer_main.counter) {
for (i=0;i<MAX_TIMERS;i++) {
if (timer_func[i].func) {
timer_func[i].counter = new_counter * timer_func[i].freq / freq;
}
}
outportb(0x43, 0x34);
outportb(0x40, (unsigned char)new_counter);
outportb(0x40, (unsigned char)(new_counter>>8));
timer_main.clock_ticks = 0;
timer_main.counter = new_counter;
timer_main.freq = freq;
} else {
t->counter = PIT_FREQ * freq / (timer_main.freq * timer_main.freq);
}
ENABLE();
return 0;
}
return -1;
}
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