arch/.unmaintained/arm-all/exec/disable.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Disable() - Stop interrupts from occurring.
   6     Lang: english
   7 */
   8
   9 #include <exec/types.h>
  10 #include <exec/execbase.h>
  11 #include <aros/libcall.h>
  12 #include <asm/registers.h>
  13
  14 /*****************************************************************************/
  15 #undef Exec
  16 #ifdef UseExecstubs
  17 #    define Exec _Exec
  18 #endif
  19
  20 /*  NAME */
  21 #include <proto/exec.h>
  22
  23         AROS_LH0(void, Disable,
  24
  25 /*  LOCATION */
  26         struct ExecBase *, SysBase, 20, Exec)
  27
  28 /*  FUNCTION
  29         This function will prevent interrupts from occuring. You can
  30         start the interrupts again with a call to Enable().
  31
  32         Note that calls to Disable() nest, and for every call to
  33         Disable() you need a matching call to Enable().
  34
  35         ***** WARNING *****
  36
  37         Using this function is considered very harmful, and it is
  38         not recommended to use this function for ** ANY ** reason.
  39
  40         It is quite possible to either crash the system, or to prevent
  41         normal activities (disk/port i/o) from occuring.
  42
  43         Note: As taskswitching is driven by the interrupts subsystem,
  44               this function has the side effect of disabling
  45               multitasking.
  46
  47     INPUTS
  48
  49     RESULT
  50         Interrupts will be disabled AFTER this call returns.
  51
  52     NOTES
  53         This function preserves all registers.
  54
  55         To prevent deadlocks calling Wait() in disabled state breaks
  56         the disable - thus interrupts may happen again.
  57
  58     EXAMPLE
  59         No you DEFINITATELY don't want to use this function.
  60
  61     BUGS
  62         The only architecture that you can rely on the registers being
  63         saved is on the Motorola mc68000 family.
  64
  65     SEE ALSO
  66         Forbid(), Permit(), Enable(), Wait()
  67
  68     INTERNALS
  69         This function must be replaced in the $(KERNEL) or $(ARCH)
  70         directories in order to do some work.
  71
  72     HISTORY
  73
  74 ******************************************************************************/
  75 {
  76 #undef Exec
  77
  78         AROS_LIBFUNC_INIT
  79
  80         /*
  81          * Disable interrupts by masking all interrupts.
  82          */
  83         SetSR(0x000000C0, 0x000000C0);
  84
  85         SysBase->IDNestCnt++;
  86
  87         AROS_LIBFUNC_EXIT
  88 } /* Disable() */