arch/m68k-mac/exec/preparecontext.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <exec/types.h>
   7 #include <aros/libcall.h>
   8 #include <exec/execbase.h>
   9 #include <exec/tasks.h>
  10 #include <exec/memory.h>
  11 #include <exec/ptrace.h>
  12 #include "etask.h"
  13 #include "exec_util.h"
  14
  15 //#error "PrepareContext() has been changed. Additional tagList param, etc."
  16 //#error "This one here needs to be rewritten!"
  17
  18 /*****************************************************************************
  19
  20     NAME */
  21
  22         AROS_LH4(BOOL, PrepareContext,
  23
  24 /*  SYNOPSIS */
  25         AROS_LHA(struct Task *, task, A0),
  26         AROS_LHA(APTR, entryPoint,   A1),
  27         AROS_LHA(APTR, fallBack,     A2),
  28         AROS_LHA(struct TagItem *, tagList, A3),
  29
  30 /*  LOCATION */
  31         struct ExecBase *, SysBase, 6, Exec)
  32
  33 /*  FUNCTION
  34         Allocates the space required to hold a new set of registers on the
  35         Stack given by stackPointer and clears the area except for pc which
  36         is set to the address given by entryPoint.
  37
  38     INPUTS
  39         task         - Pointer to the new task
  40         entryPoint   - Address of the function to call when the new context
  41                        becomes active.
  42         fallBack     - Address to be called when the entryPoint function ended
  43                        with an rts.
  44         tagList      -
  45
  46     RESULT
  47         The new Stackpointer with the underlying context.
  48
  49     NOTES
  50         This function is for internal use by exec only.
  51
  52         This function is processor dependant.
  53
  54     EXAMPLE
  55
  56     BUGS
  57
  58     SEE ALSO
  59         SwitchTasks()
  60
  61     INTERNALS
  62
  63     HISTORY
  64
  65 ******************************************************************************/
  66 {
  67         AROS_LIBFUNC_INIT
  68
  69         struct pt_regs *regs;
  70
  71         UBYTE *sp = (UBYTE *)task->tc_SPReg;
  72
  73         /* Push fallBack address */
  74         sp -= sizeof(APTR);
  75         *(APTR *)sp = fallBack;
  76
  77         if (!(task->tc_Flags & TF_ETASK)) {
  78           *(ULONG *)0x0bad0001=0;
  79           return FALSE;
  80         }
  81
  82         GetIntETask (task)->iet_Context = AllocTaskMem (task
  83             , SIZEOF_ALL_REGISTERS
  84             , MEMF_PUBLIC|MEMF_CLEAR
  85         );
  86
  87         if (!(regs  = (struct pt_regs *)GetIntETask(task)->iet_Context)) {
  88           *(ULONG *)0x0bad0003=0;
  89           return FALSE;
  90         }
  91
  92         regs->usp = sp;
  93         regs->pc  = (ULONG)entryPoint;
  94
  95         task->tc_SPReg = sp;
  96
  97         return TRUE;
  98         AROS_LIBFUNC_EXIT
  99 }