usr.bin/doscmd/timer.c

   1 /*
   2 ** No copyright?!
   3 **
   4 ** $FreeBSD$
   5 */
   6 #include "doscmd.h"
   7
   8 static void
   9 int08(regcontext_t *REGS)
  10 {
  11     softint(0x1c);
  12 }
  13
  14 static void
  15 int1c(regcontext_t *REGS)
  16 {
  17 }
  18
  19 unsigned char timer;
  20
  21 static u_char
  22 inb_timer(int port)
  23 {
  24     return (--timer);
  25 }
  26
  27 void
  28 timer_init(void)
  29 {
  30     u_long              vec;
  31     struct itimerval    itv;
  32
  33     vec = insert_hardint_trampoline();
  34     ivec[0x08] = vec;
  35     register_callback(vec, int08, "int 08");
  36
  37     vec = insert_softint_trampoline();
  38     ivec[0x1c] = vec;
  39     register_callback(vec, int1c, "int 1c");
  40
  41     define_input_port_handler(0x42, inb_timer);
  42     define_input_port_handler(0x40, inb_timer);
  43
  44     itv.it_interval.tv_sec = 0;
  45     itv.it_interval.tv_usec = 54925; /* 1193182/65536 times per second */
  46     itv.it_value.tv_sec = 0;
  47     itv.it_value.tv_usec = 54925;        /* 1193182/65536 times per second */
  48     if (! timer_disable)
  49         setitimer(ITIMER_REAL, &itv, 0);
  50 }