src/timer.c


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#include <stdio.h>
#include <stdint.h>
#include <go32.h>
#include <dpmi.h>

/* updates 18.2 times per second by default */
volatile uint32_t ticks = 0;

static _go32_dpmi_seginfo old_handler, new_handler;

static void timer_handler()
{
    ticks++;
}

void timer_init()
{
    _go32_dpmi_get_protected_mode_interrupt_vector(0x1c, &old_handler);
    new_handler.pm_offset = (unsigned long)timer_handler;
    new_handler.pm_selector = _go32_my_cs();
    _go32_dpmi_chain_protected_mode_interrupt_vector(0x1c, &new_handler);
}

void timer_free()
{
    if (_go32_dpmi_set_protected_mode_interrupt_vector(0x1c, &old_handler) == -1)
        fprintf(stderr, "Failed to free the timer :(\n");
}