rom/exec/disable.c

   1 /*
   2     Copyright © 1995-2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Disable() - Stop interrupts from occurring.
   6     Lang: english
   7 */
   8
   9 #define DEBUG 0
  10
  11 #include <exec/types.h>
  12 #include <exec/execbase.h>
  13 #include <aros/libcall.h>
  14 #include <aros/atomic.h>
  15 #include <proto/kernel.h>
  16
  17 #include "exec_intern.h"
  18
  19 /*****************************************************************************/
  20 #undef  Exec
  21 #ifdef UseExecstubs
  22 #    define Exec _Exec
  23 #endif
  24
  25 /*  NAME */
  26 #include <proto/exec.h>
  27
  28         AROS_LH0(void, Disable,
  29
  30 /*  LOCATION */
  31         struct ExecBase *, SysBase, 20, Exec)
  32
  33 /*  FUNCTION
  34         This function will prevent interrupts from occuring. You can
  35         start the interrupts again with a call to Enable().
  36
  37         Note that calls to Disable() nest, and for every call to
  38         Disable() you need a matching call to Enable().
  39
  40         ***** WARNING *****
  41
  42         Using this function is considered very harmful, and it is
  43         not recommended to use this function for ** ANY ** reason.
  44
  45         It is quite possible to either crash the system, or to prevent
  46         normal activities (disk/port i/o) from occuring.
  47
  48         Note: As taskswitching is driven by the interrupts subsystem,
  49               this function has the side effect of disabling
  50               multitasking.
  51
  52     INPUTS
  53
  54     RESULT
  55         Interrupts will be disabled AFTER this call returns.
  56
  57     NOTES
  58         This function preserves all registers.
  59
  60         To prevent deadlocks calling Wait() in disabled state breaks
  61         the disable - thus interrupts may happen again.
  62
  63     EXAMPLE
  64         No you DEFINITELY don't want to use this function.
  65
  66     BUGS
  67         The only architecture that you can rely on the registers being
  68         saved is on the Motorola mc68000 family.
  69
  70     SEE ALSO
  71         Forbid(), Permit(), Enable(), Wait()
  72
  73     INTERNALS
  74         This function must be replaced in the $(KERNEL) or $(ARCH)
  75         directories in order to do some work.
  76
  77 ******************************************************************************/
  78 {
  79 #undef Exec
  80
  81     AROS_LIBFUNC_INIT
  82
  83     D(bug("[Exec] Disable()\n");)
  84
  85     if (KernelBase)
  86         KrnCli();
  87
  88     IDNESTCOUNT_INC;
  89
  90     D(bug("[Exec] Disable: IDNESTCOUNT = %d\n", IDNESTCOUNT_GET);)
  91
  92     AROS_LIBFUNC_EXIT
  93 } /* Disable() */