arch/i386-pc/exec/wait.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Wait for some signal.
   6     Lang: english
   7 */
   8 #include <exec/execbase.h>
   9 #include <aros/libcall.h>
  10 #include <proto/exec.h>
  11
  12 /*****************************************************************************
  13
  14     NAME */
  15
  16 extern void Exec_Switch();
  17
  18
  19         AROS_LH1(ULONG, Wait,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(ULONG, signalSet, D0),
  23
  24 /*  LOCATION */
  25         struct ExecBase *, SysBase, 53, Exec)
  26
  27 /*  FUNCTION
  28         Wait until some signals are sent to the current task. If any signal
  29         of the specified set is already set when entering this function it
  30         returns immediately. Since almost any event in the OS can send a
  31         signal to your task if you specify it to do so signals are a very
  32         powerful mechanism.
  33
  34     INPUTS
  35         signalSet - The set of signals to wait for.
  36
  37     RESULT
  38         The set of active signals.
  39
  40     NOTES
  41         Naturally it's not allowed to wait in supervisor mode.
  42
  43         Calling Wait() breaks an active Disable() or Forbid().
  44
  45     EXAMPLE
  46
  47     BUGS
  48
  49     SEE ALSO
  50         Signal(), SetSignal(), AllocSignal(), FreeSignal()
  51
  52     INTERNALS
  53
  54     HISTORY
  55
  56 ******************************************************************************/
  57 {
  58     AROS_LIBFUNC_INIT
  59
  60     ULONG rcvd;
  61     struct Task *me;
  62
  63     /* Get pointer to current task - I'll need it very often */
  64     me = FindTask (NULL);
  65
  66     /* Protect the task lists against access by other tasks. */
  67     Disable();
  68
  69     /* If at least one of the signals is already set do not wait. */
  70     while(!(me->tc_SigRecvd&signalSet))
  71     {
  72         BYTE old_TDNestCnt;
  73
  74         /* Set the wait signal mask */
  75         me->tc_SigWait=signalSet;
  76
  77         /*
  78             Clear TDNestCnt (because Switch() will not care about it),
  79             but memorize it first. IDNestCnt is handled by Switch().
  80             This could as well be stored in a local variable which makes
  81             the tc_TDNestCnt field somehow redundant.
  82         */
  83         old_TDNestCnt=SysBase->TDNestCnt;
  84         SysBase->TDNestCnt=-1;
  85
  86         /* Move current task to the waiting list. */
  87         me->tc_State=TS_WAIT;
  88
  89         /*
  90                 remove it from what!?
  91                 sheutlin
  92         */
  93 //        me->tc_Node.ln_Pred->ln_Succ = me->tc_Node.ln_Succ;
  94 //      me->tc_Node.ln_Succ->ln_Pred = me->tc_Node.ln_Pred;
  95
  96         Enqueue(&SysBase->TaskWait,&me->tc_Node);
  97
  98         /* And switch to the next ready task. */
  99         Supervisor(__AROS_GETVECADDR(SysBase,9));
 100
 101 //      Reschedule(me);
 102
 103         /*
 104             OK. Somebody awakened me. This means that either the
 105             signals are there or it's just a finished task exception.
 106             Test again to be sure (see above).
 107         */
 108
 109         /* Restore TDNestCnt. */
 110         SysBase->TDNestCnt=old_TDNestCnt;
 111     }
 112     /* Get active signals. */
 113     rcvd=me->tc_SigRecvd&signalSet;
 114
 115     /* And clear them. */
 116     me->tc_SigRecvd&=~signalSet;
 117
 118     /* All done. */
 119     Enable();
 120
 121     return rcvd;
 122     AROS_LIBFUNC_EXIT
 123 }
 124