arch/m68k-mac/exec/switch.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Native version of Switch().
   6     Lang: english
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <proto/exec.h>
  11
  12 AROS_LH0(void, Switch,
  13     struct ExecBase *, SysBase, 9, Exec)
  14 {
  15     AROS_LIBFUNC_INIT
  16
  17     struct Task *this = SysBase->ThisTask;
  18
  19     /*
  20         If the state is not TS_RUN then the task is already in a list
  21     */
  22
  23     Disable();
  24
  25     if( (this->tc_State != TS_RUN)
  26          && !(this->tc_Flags & TF_EXCEPT) )
  27     {
  28         /*      Its quite possible that they have interrupts Disabled(),
  29             we should fix that here, otherwise we can't switch.
  30
  31             We can't call the dispatcher because we need a signal,
  32             lets just create one.
  33
  34             Have to set the dispatch-required flag.
  35             I use SIGUSR1 (maps to SoftInt) because it has less effect on
  36             the system clock, and is probably quicker.
  37         */
  38
  39         SysBase->AttnResched |= 0x8000;
  40         __asm__ __volatile__ ("move.l %d7,-(%sp)\n\t"
  41                               "clr.l %d7\n\t"
  42                               "trap #1\n\t"
  43                               "move.l (%sp)+,%d7\n\t");
  44     }
  45
  46     Enable();
  47
  48     AROS_LIBFUNC_EXIT
  49 } /* Switch() */