arch/all-pc/kernel/kernel_timer.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <hardware/pit.h>
   7
   8 #include "kernel_base.h"
   9 #include "kernel_debug.h"
  10 #include "kernel_timer.h"
  11
  12 #define D(x)
  13
  14 /* See timer/ticks.c for the explanation */
  15 static const unsigned int timer_rpr = 3599597124UL;
  16
  17 static inline unsigned int usec2tick(unsigned int usec)
  18 {
  19     unsigned int ret = 0;
  20
  21     asm volatile("divl %2":"+a"(ret),"+d"(usec):"m"(timer_rpr));
  22     return ret;
  23 }
  24
  25 void pit_udelay(unsigned int usec)
  26 {
  27     unsigned int start = usec2tick(usec);
  28
  29     D(bug("[PIT] udelay: %d usec = %d ticks\n", usec, start));
  30
  31     pit_start(start);
  32     pit_wait(start);
  33 }