arch/ppc-all/exec/preparecontext.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: PrepareContext() - Prepare a task context for dispatch, PowerPC version
   6     Lang: english
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <exec/memory.h>
  11 #include <utility/tagitem.h>
  12 #include <proto/kernel.h>
  13 #include <aros/ppc/cpucontext.h>
  14
  15 #include "exec_intern.h"
  16 #include "exec_util.h"
  17
  18 #define _PUSH(sp, val) *--sp = (IPTR)val
  19
  20 BOOL PrepareContext(struct Task *task, APTR entryPoint, APTR fallBack,
  21                     const struct TagItem *tagList, struct ExecBase *SysBase)
  22 {
  23     struct ExceptionContext *ctx;
  24
  25     if (!(task->tc_Flags & TF_ETASK) )
  26         return FALSE;
  27
  28     ctx = KrnCreateContext();
  29     task->tc_UnionETask.tc_ETask->et_RegFrame = ctx;
  30     if (!ctx)
  31         return FALSE;
  32
  33     /* Set up arguments first */
  34     while(tagList)
  35     {
  36         switch(tagList->ti_Tag)
  37         {
  38         case TAG_MORE:
  39             tagList = (const struct TagItem *)tagList->ti_Data;
  40             continue;
  41
  42         case TAG_SKIP:
  43             tagList += tagList->ti_Data;
  44             break;
  45
  46         case TAG_DONE:
  47             tagList = NULL;
  48             break;
  49
  50 #define HANDLEARG(x)                                       \
  51         case TASKTAG_ARG ## x:                             \
  52             ctx->gpr[3 + x - 1] = (ULONG)tagList->ti_Data; \
  53             break;
  54
  55         HANDLEARG(1)
  56         HANDLEARG(2)
  57         HANDLEARG(3)
  58         HANDLEARG(4)
  59         HANDLEARG(5)
  60         HANDLEARG(6)
  61         HANDLEARG(7)
  62         HANDLEARG(8)
  63         }
  64
  65         if (tagList) tagList++;
  66     }
  67
  68     /* Next we set up return address */
  69     ctx->lr = (ULONG)fallBack;
  70
  71     /* Then set up the frame to be used by Dispatch() */
  72     ctx->gpr[1] = (ULONG)task->tc_SPReg;
  73     ctx->ip     = (ULONG)entryPoint;
  74
  75     return TRUE;
  76 } /* PrepareContext() */