arch/all-unix/exec/preparecontext.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: i386unix version of PrepareContext().
   6     Lang: english
   7 */
   8
   9 #include <exec/types.h>
  10 #include <exec/execbase.h>
  11 #include <exec/memory.h>
  12 #include <utility/tagitem.h>
  13 #include <sigcore.h>
  14 #include "etask.h"
  15 #include "exec_util.h"
  16
  17 #include <aros/libcall.h>
  18
  19 AROS_LH4(BOOL, PrepareContext,
  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     struct ExecBase *, SysBase, 6, Exec)
  25 {
  26     AROS_LIBFUNC_INIT
  27
  28     IPTR args[8] = {0};
  29     WORD numargs = 0;
  30
  31     while(tagList)
  32     {
  33         switch(tagList->ti_Tag)
  34         {
  35             case TAG_MORE:
  36                 tagList = (struct TagItem *)tagList->ti_Data;
  37                 continue;
  38
  39             case TAG_SKIP:
  40                 tagList += tagList->ti_Data;
  41                 break;
  42
  43             case TAG_DONE:
  44                 tagList = NULL;
  45                 break;
  46
  47             #define HANDLEARG(x) \
  48             case TASKTAG_ARG ## x: \
  49                 args[x - 1] = (IPTR)tagList->ti_Data; \
  50                 if (x > numargs) numargs = x; \
  51                 break;
  52
  53             HANDLEARG(1)
  54             HANDLEARG(2)
  55             HANDLEARG(3)
  56             HANDLEARG(4)
  57             HANDLEARG(5)
  58             HANDLEARG(6)
  59             HANDLEARG(7)
  60             HANDLEARG(8)
  61
  62             #undef HANDLEARG
  63         }
  64
  65         if (tagList) tagList++;
  66     }
  67
  68     /*
  69         There is not much to do here, or at least that is how it
  70         appears. Most of the work is done in the sigcore.h macros.
  71     */
  72
  73     if (!(task->tc_Flags & TF_ETASK) )
  74         return FALSE;
  75
  76     GetIntETask (task)->iet_Context = AllocTaskMem (task
  77         , SIZEOF_ALL_REGISTERS
  78         , MEMF_PUBLIC|MEMF_CLEAR
  79     );
  80
  81     if (!GetIntETask (task)->iet_Context)
  82         return FALSE;
  83
  84     if (numargs)
  85     {
  86         #ifdef PREPARE_INITIAL_ARGS
  87
  88         PREPARE_INITIAL_ARGS(task, args, numargs);
  89
  90         #else
  91
  92         /* Assume C function gets all param on stack */
  93
  94         while(numargs--)
  95         {
  96             _PUSH(GetSP(task), args[numargs]);
  97         }
  98
  99         #endif
 100     }
 101
 102     #ifdef PREPARE_RETURN_ADDRESS
 103
 104     PREPARE_RETURN_ADDRESS(task, fallBack);
 105
 106     #else
 107
 108     /* First we push the return address */
 109     _PUSH(GetSP(task), fallBack);
 110
 111     #endif
 112
 113     /* Then set up the frame to be used by Dispatch() */
 114     PREPARE_INITIAL_FRAME(GetSP(task), entryPoint);
 115     PREPARE_INITIAL_CONTEXT(task, entryPoint);
 116
 117     /* We return the new stack pointer back to the caller. */
 118     return TRUE;
 119
 120     AROS_LIBFUNC_EXIT
 121 }