usr.bin/doscmd/timer.c

   1 /*
   2  * No copyright?!
   3  *
   4  * $FreeBSD: src/usr.bin/doscmd/timer.c,v 1.2.2.2 2002/04/25 11:04:51 tg Exp $
   5  * $DragonFly: src/usr.bin/doscmd/timer.c,v 1.2 2003/06/17 04:29:26 dillon Exp $
   6  */
   7 #include "doscmd.h"
   8
   9 static void
  10 int08(regcontext_t *REGS __unused)
  11 {
  12     *(u_long *)&BIOSDATA[0x6c] += 1;    /* ticks since midnight */
  13     while (*(u_long *)&BIOSDATA[0x6c] >= 24*60*6*182) {
  14         *(u_long *)&BIOSDATA[0x6c] -= 24*60*6*182;
  15         BIOSDATA[0x70]++;               /* # times past mn */
  16     }
  17     /* What is the real BIOS' sequence? */
  18     send_eoi();
  19     softint(0x1c);
  20 }
  21
  22 static void
  23 int1c(regcontext_t *REGS __unused)
  24 {
  25 }
  26
  27 unsigned char timer;
  28
  29 static u_char
  30 inb_timer(int port __unused)
  31 {
  32     return (--timer);
  33 }
  34
  35 void
  36 timer_init(void)
  37 {
  38     u_long              vec;
  39     struct itimerval    itv;
  40     struct timeval      tv;
  41     time_t              tv_sec;
  42     struct timezone     tz;
  43     struct tm           tm;
  44
  45     vec = insert_hardint_trampoline();
  46     ivec[0x08] = vec;
  47     register_callback(vec, int08, "int 08");
  48
  49     vec = insert_softint_trampoline();
  50     ivec[0x1c] = vec;
  51     register_callback(vec, int1c, "int 1c");
  52
  53     define_input_port_handler(0x42, inb_timer);
  54     define_input_port_handler(0x40, inb_timer);
  55
  56     /* Initialize time counter BIOS variable. */
  57     gettimeofday(&tv, &tz);
  58     tv_sec = tv.tv_sec;
  59     tm = *localtime(&tv_sec);
  60     *(u_long *)&BIOSDATA[0x6c] =
  61         (((tm.tm_hour * 60 + tm.tm_min) * 60) + tm.tm_sec) * 182 / 10;
  62
  63     itv.it_interval.tv_sec = 0;
  64     itv.it_interval.tv_usec = 54925;    /* 1193182/65536 times per second */
  65     itv.it_value.tv_sec = 0;
  66     itv.it_value.tv_usec = 54925;       /* 1193182/65536 times per second */
  67     if (! timer_disable)
  68         setitimer(ITIMER_REAL, &itv, 0);
  69 }