arch/arm-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, ARM version.
   6     Lang: english
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <exec/memory.h>
  11 #include <utility/tagitem.h>
  12 #include <proto/arossupport.h>
  13 #include <proto/kernel.h>
  14 #include <aros/arm/cpucontext.h>
  15
  16 #include "exec_intern.h"
  17 #include "exec_util.h"
  18 #if defined(__AROSEXEC_SMP__)
  19 #include "etask.h"
  20 #endif
  21
  22 BOOL PrepareContext(struct Task *task, APTR entryPoint, APTR fallBack,
  23                     const struct TagItem *tagList, struct ExecBase *SysBase)
  24 {
  25     struct TagItem *t;
  26     struct ExceptionContext *ctx;
  27     ULONG args[4] = {0};
  28     int numargs = 0;
  29     STACKULONG *sp = task->tc_SPReg;
  30
  31     if (!(task->tc_Flags & TF_ETASK) )
  32         return FALSE;
  33
  34     ctx = KrnCreateContext();
  35     task->tc_UnionETask.tc_ETask->et_RegFrame = ctx;
  36     if (!ctx)
  37         return FALSE;
  38
  39     /* Set up function arguments */
  40     while((t = LibNextTagItem((struct TagItem **)&tagList)))
  41     {
  42         switch(t->ti_Tag)
  43         {
  44 #if defined(__AROSEXEC_SMP__)
  45             case TASKTAG_AFFINITY:
  46                 IntETask(task->tc_UnionETask.tc_ETask)->iet_CpuAffinity = t->ti_Data;
  47                 break;
  48 #endif
  49 #define REGARG(x)                       \
  50         case TASKTAG_ARG ## x:          \
  51             ctx->r[x - 1] = t->ti_Data; \
  52             break;
  53
  54 #define STACKARG(x)                     \
  55         case TASKTAG_ARG ## x:          \
  56             args[x - 5] = t->ti_Data;   \
  57             if (x - 4 > numargs)        \
  58                 numargs = x - 4;        \
  59             break;
  60
  61         REGARG(1)
  62         REGARG(2)
  63         REGARG(3)
  64         REGARG(4)
  65         STACKARG(5)
  66         STACKARG(6)
  67         STACKARG(7)
  68         STACKARG(8)
  69         }
  70     }
  71
  72     /* Last four arguments are put on stack */
  73     while (numargs > 0)
  74         *--sp = args[--numargs];
  75
  76     task->tc_SPReg = sp;
  77
  78     /* Now prepare return address */
  79     ctx->r[11] = 0;
  80     ctx->lr = (ULONG)fallBack;
  81
  82     ctx->Flags = 0;
  83
  84     /* Then set up the frame to be used by Dispatch() */
  85     ctx->sp = (ULONG)task->tc_SPReg;
  86     ctx->pc = (ULONG)entryPoint;
  87
  88     return TRUE;
  89 } /* PrepareContext() */