rom/exec/signal.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Send some signal to a given task
   6     Lang: english
   7 */
   8 #include <exec/execbase.h>
   9 #include <aros/libcall.h>
  10 #include <proto/exec.h>
  11 #include <aros/debug.h>
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16
  17         AROS_LH2(void, Signal,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(struct Task *,     task,      A1),
  21         AROS_LHA(ULONG,             signalSet, D0),
  22
  23 /*  LOCATION */
  24         struct ExecBase *, SysBase, 54, Exec)
  25
  26 /*  FUNCTION
  27         Send some signals to a given task. If the task is currently waiting
  28         on these signals, has a higher priority as the current one and if
  29         taskswitches are allowed the new task begins to run immediately.
  30
  31     INPUTS
  32         task      - Pointer to task structure.
  33         signalSet - The set of signals to send to the task.
  34
  35     RESULT
  36
  37     NOTES
  38         This function may be used from interrupts.
  39
  40     EXAMPLE
  41
  42     BUGS
  43
  44     SEE ALSO
  45         AllocSignal(), FreeSignal(), Wait(), SetSignal(), SetExcept()
  46
  47     INTERNALS
  48
  49 ******************************************************************************/
  50 {
  51     AROS_LIBFUNC_INIT
  52
  53     /* Protect the task lists against other tasks that may use Signal(). */
  54     Disable();
  55
  56     /* Set the signals in the task structure. */
  57     task->tc_SigRecvd|=signalSet;
  58
  59     /* Do those bits raise exceptions? */
  60     if(task->tc_SigExcept&task->tc_SigRecvd)
  61     {
  62         /* Yes. Set the exception flag. */
  63         task->tc_Flags|=TF_EXCEPT;
  64
  65         /* task is running? Raise the exception or defer it for later. */
  66         if(task->tc_State==TS_RUN)
  67         {
  68             /* Are taskswitches allowed? (Don't count own Disable() here) */
  69             if(SysBase->TDNestCnt>=0||SysBase->IDNestCnt>0)
  70                 /* No. Store it for later. */
  71                 SysBase->AttnResched|=0x80;
  72             else
  73             {
  74                 /* Switches are allowed. Move the current task away. */
  75                 SysBase->ThisTask->tc_State=TS_READY;
  76                 Enqueue(&SysBase->TaskReady,&SysBase->ThisTask->tc_Node);
  77
  78                 /* And force a rescedule. */
  79                 Switch();
  80             }
  81
  82             /* All done. */
  83             Enable();
  84             return;
  85         }
  86     }
  87
  88     /*
  89         Is the task receiving the signals waiting on them
  90         (or on a exception) ?
  91     */
  92     if(task->tc_State==TS_WAIT&&
  93        (task->tc_SigRecvd&(task->tc_SigWait|task->tc_SigExcept)))
  94     {
  95         /* Yes. Move him to the ready list. */
  96         task->tc_State=TS_READY;
  97         Remove(&task->tc_Node);
  98         Enqueue(&SysBase->TaskReady,&task->tc_Node);
  99
 100         /* Has it a higher priority as the current one? */
 101         if(task->tc_Node.ln_Pri>SysBase->ThisTask->tc_Node.ln_Pri)
 102         {
 103             /*
 104                 Yes. A taskswitch is necessary. Prepare one if possible.
 105                 (If the current task is not running it is already moved)
 106             */
 107             if(SysBase->ThisTask->tc_State==TS_RUN)
 108             {
 109                 /* Are taskswitches allowed? */
 110                 if(SysBase->TDNestCnt>=0||SysBase->IDNestCnt>0)
 111                 {
 112                     /* No. Store it for later. */
 113                     SysBase->AttnResched|=0x80;
 114                 }
 115                 else
 116                 {
 117                     /* Switches are allowed. Move the current task away. */
 118                     SysBase->ThisTask->tc_State=TS_READY;
 119                     Enqueue(&SysBase->TaskReady,&SysBase->ThisTask->tc_Node);
 120
 121                     /* And force a rescedule. */
 122                     Switch();
 123                 }
 124             }
 125         }
 126     }
 127
 128     Enable();
 129     AROS_LIBFUNC_EXIT
 130 } /* Signal() */
 131