arch/.unmaintained/m68k-emul/disable.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Exec function Disable
   6     Lang: english
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <signal.h>
  11
  12 void _os_disable (void);
  13
  14 /******************************************************************************
  15
  16     NAME
  17         #include <proto/exec.h>
  18
  19         AROS_LH0(void, Disable,
  20
  21     LOCATION
  22         struct ExecBase *, SysBase, 20, Exec)
  23
  24     FUNCTION
  25         This function disables the delivery of all interrupts until a
  26         matching call to Enable() is done. This implies a Forbid(). Since
  27         the system needs the regular delivery of all interrupts it is
  28         forbidden to disable them for longer than ~250 microseconds.
  29
  30         THIS CALL IS VERY DANGEROUS!!!
  31
  32         Do not use it without thinking very well about it or better do not
  33         use it at all. Most of the time you can live without it by using
  34         semaphores or similar.
  35
  36         Calls to Disable() nest, i.e. for each call to Disable() you need
  37         one call to Enable().
  38
  39     INPUTS
  40         None.
  41
  42     RESULT
  43         None.
  44
  45     NOTES
  46         This function preserves all registers.
  47
  48         This function may be used from interrupts to disable all higher
  49         priority interrupts. Lower priority interrupts are disabled anyway.
  50
  51         To prevent deadlocks calling Wait() in disabled state breaks the
  52         disable - thus interrupts and taskswitches may happen again.
  53
  54     EXAMPLE
  55
  56     BUGS
  57
  58     SEE ALSO
  59         Forbid(), Permit(), Enable(), Wait()
  60
  61     INTERNALS
  62
  63     HISTORY
  64
  65 ******************************************************************************/
  66
  67 /* The real function is written in assembler as stub which calls me */
  68 void _Disable (struct ExecBase * SysBase)
  69 {
  70     _os_disable ();
  71
  72     SysBase->IDNestCnt ++;
  73 } /* _Disable */
  74
  75 /* The real function is written in assembler as stub which calls me */
  76 void _os_disable (void)
  77 {
  78     sigset_t set;
  79
  80     sigfillset (&set);
  81
  82     sigprocmask (SIG_BLOCK, &set, NULL);
  83 } /* disable */