rom/exec/preparecontext.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: PrepareContext() - Prepare a task context for dispatch.
   6     Lang: english
   7 */
   8
   9 #include <exec/types.h>
  10 #include <aros/libcall.h>
  11 #include <exec/execbase.h>
  12 #include <utility/tagitem.h>
  13
  14 /*****i***********************************************************************
  15
  16     NAME */
  17         AROS_LH4(BOOL, PrepareContext,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(struct Task *, task,    A0),
  21         AROS_LHA(APTR, entryPoint,      A1),
  22         AROS_LHA(APTR, fallBack,        A2),
  23         AROS_LHA(struct TagItem *, tagList, A3),
  24
  25 /*  LOCATION */
  26         struct ExecBase *, SysBase, 6, Exec)
  27
  28 /*  FUNCTION
  29         Prepare the context (set of registers) for a new task.
  30         The context/stack will be set so that when the entryPoint
  31         function returns, the fallback function will be called.
  32
  33     INPUTS
  34         task            -   Pointer to task
  35         entryPoint      -   Function to call when the new context
  36                             comes alive.
  37         fallBack        -   Address of the function to be called
  38                             when the entryPoint function returns.
  39         tagList         -   Additional options. Like for passing
  40                             arguments to the entryPoint() functions.
  41
  42     RESULT
  43         TRUE on success. FALSE on failure.
  44
  45     NOTES
  46         This function is very CPU dependant. In fact it can differ
  47         over different models of the same processor family.
  48
  49     EXAMPLE
  50
  51     BUGS
  52
  53     SEE ALSO
  54         Dispatch()
  55
  56     INTERNALS
  57         This function is required to be implemented in the $(KERNEL).
  58
  59 ******************************************************************************/
  60 {
  61     AROS_LIBFUNC_INIT
  62
  63     /* This function is too CPU dependant to be described here, but
  64         basically you effectively do a state save (similar to in
  65         Dispatch()) but of a context that has not been run yet.
  66     */
  67
  68 #ifndef __CXREF__
  69 #error The PrepareContext() function was not implemented in the kernel.
  70 #endif
  71
  72     AROS_LIBFUNC_EXIT
  73 } /* PrepareContext() */