/*
 * Copyright (c) 2001-2010 Stephen Williams (steve@icarus.com)
 *
 *    This source code is free software; you can redistribute it
 *    and/or modify it in source code form under the terms of the GNU
 *    General Public License as published by the Free Software
 *    Foundation; either version 2 of the License, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

/*
 * This file keeps the table of system/task definitions. This table is
 * built up before the input source file is parsed, and is used by the
 * compiler when %vpi_call statements are encountered.
 */
# include  "vpi_priv.h"
# include  "vthread.h"
# include  "compile.h"
# include  "config.h"
#ifdef CHECK_WITH_VALGRIND
# include  "vvp_cleanup.h"
#endif
# include  <cstdio>
# include  <cstdlib>
# include  <cstring>
# include  <cassert>
# include  "ivl_alloc.h"

static const struct __vpirt vpip_systf_def_rt = {
      vpiUserSystf,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0
};

static vpiHandle systask_handle(int type, vpiHandle ref)
{
      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;
      assert((ref->vpi_type->type_code == vpiSysTaskCall)
	     || (ref->vpi_type->type_code == vpiSysFuncCall));

      switch (type) {
	  case vpiScope:
	    return &rfp->scope->base;

	  case vpiUserSystf:
	      /* Assert that vpiUserDefn is true! */
	    assert(rfp->defn->is_user_defn);
	    return &rfp->defn->base;

	  default:
	    return 0;
      };
}

static int systask_get(int type, vpiHandle ref)
{
      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      assert((ref->vpi_type->type_code == vpiSysTaskCall)
	     || (ref->vpi_type->type_code == vpiSysFuncCall));

      switch (type) {
	    /* This is not the correct way to get this information, but
	     * some of the code that implements the acc and tf routines
	     * use this method so we will keep it in for now. */
	  case vpiTimeUnit:
	    return rfp->scope->time_units;
	  case vpiTimePrecision:
	    return rfp->scope->time_precision;

	  case vpiLineNo:
	    return rfp->lineno;

	  case vpiUserDefn:
	    return rfp->defn->is_user_defn;

	  default:
	    return vpiUndefined;
      }
}

// support getting vpiSize for a system function call
static int sysfunc_get(int type, vpiHandle ref)
{
      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      assert(ref->vpi_type->type_code == vpiSysFuncCall);

      switch (type) {
	  case vpiSize:
	    return rfp->vwid;

	  case vpiLineNo:
	    return rfp->lineno;

	  case vpiUserDefn:
	    return rfp->defn->is_user_defn;

	  default:
	    return vpiUndefined;
      }
}

/*
 * the get_str function only needs to support vpiName
 */

static char *systask_get_str(int type, vpiHandle ref)
{
      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      assert((ref->vpi_type->type_code == vpiSysTaskCall)
	     || (ref->vpi_type->type_code == vpiSysFuncCall));

      switch (type) {
          case vpiFile:
            assert(rfp->file_idx < file_names.size());
            return simple_set_rbuf_str(file_names[rfp->file_idx]);

          case vpiName:
            return simple_set_rbuf_str(rfp->defn->info.tfname);
      }

      return 0;
}

/*
 * the iter function only supports getting an iterator of the
 * arguments. This works equally well for tasks and functions.
 */
static vpiHandle systask_iter(int, vpiHandle ref)
{
      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;
      assert((ref->vpi_type->type_code == vpiSysTaskCall)
	     || (ref->vpi_type->type_code == vpiSysFuncCall));

      if (rfp->nargs == 0)
	    return 0;

      return vpip_make_iterator(rfp->nargs, rfp->args, false);
}

static const struct __vpirt vpip_systask_rt = {
      vpiSysTaskCall,
      systask_get,
      systask_get_str,
      0,
      0,
      systask_handle,
      systask_iter,
      0,
      0,
      0,
      0
};


/*
 * A value *can* be put to a vpiSysFuncCall object. This is how the
 * return value is set. The value that is given should be converted to
 * bits and set into the thread space bits that were selected at
 * compile time.
 */
static vpiHandle sysfunc_put_value(vpiHandle ref, p_vpi_value vp, int)
{
      assert(ref->vpi_type->type_code == vpiSysFuncCall);

      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      rfp->put_value = true;

      assert(rfp->vbit >= 4);

      switch (vp->format) {

	  case vpiIntVal: {
		long val = vp->value.integer;
		for (int idx = 0 ;  idx < rfp->vwid ;  idx += 1) {
		      vthread_put_bit(vpip_current_vthread,
				      rfp->vbit+idx, (val&1)? BIT4_1 :BIT4_0);
		      val >>= 1;
		}
		break;
	  }

	  case vpiTimeVal:
		for (int idx = 0 ;  idx < rfp->vwid ;  idx += 1) {
		      PLI_INT32 word;
		      if (idx >= 32)
			    word = vp->value.time->high;
		      else
			    word = vp->value.time->low;

		      word >>= idx % 32;

		      vthread_put_bit(vpip_current_vthread,
				      rfp->vbit+idx, (word&1)? BIT4_1 :BIT4_0);
		}
		break;

	  case vpiScalarVal:
	    switch (vp->value.scalar) {
		case vpi0:
		  vthread_put_bit(vpip_current_vthread, rfp->vbit, BIT4_0);
		  break;
		case vpi1:
		  vthread_put_bit(vpip_current_vthread, rfp->vbit, BIT4_1);
		  break;
		case vpiX:
		  vthread_put_bit(vpip_current_vthread, rfp->vbit, BIT4_X);
		  break;
		case vpiZ:
		  vthread_put_bit(vpip_current_vthread, rfp->vbit, BIT4_Z);
		  break;
		default:
		  fprintf(stderr, "Unsupported value %d.\n",
		          (int)vp->value.scalar);
		  assert(0);
	    }
	    break;

	  case vpiStringVal: {
	    unsigned len = strlen(vp->value.str) - 1;
	    assert(len*8 <= (unsigned)rfp->vwid);
	    for (unsigned wdx = 0 ;  wdx < (unsigned)rfp->vwid ;  wdx += 8) {
		  unsigned word = wdx / 8;
		  char bits;
		  if (word <= len) {
			bits = vp->value.str[len-word];
		  } else {
			bits = 0;
		  }
		  for (unsigned idx = 0 ;  (wdx+idx) < (unsigned)rfp->vwid &&
		       idx < 8; idx += 1) {
			vvp_bit4_t bit4 = BIT4_0;
			if (bits & 1) bit4 = BIT4_1;
			vthread_put_bit(vpip_current_vthread,
					rfp->vbit+wdx+idx, bit4);
			bits >>= 1;
		  }
	    }
	    break;
	  }

	  case vpiVectorVal:

	    for (unsigned wdx = 0 ;  wdx < (unsigned)rfp->vwid ;  wdx += 32) {
		  unsigned word = wdx / 32;
		  unsigned long aval = vp->value.vector[word].aval;
		  unsigned long bval = vp->value.vector[word].bval;

		  for (unsigned idx = 0 ;  (wdx+idx) < (unsigned)rfp->vwid &&
		       idx < 32; idx += 1)
		  {
			int bit = (aval&1) | ((bval<<1)&2);
			vvp_bit4_t bit4;

			switch (bit) {
			    case 0:
			      bit4 = BIT4_0;
			      break;
			    case 1:
			      bit4 = BIT4_1;
			      break;
			    case 2:
			      bit4 = BIT4_Z;
			      break;
			    case 3:
			      bit4 = BIT4_X;
			      break;
			    default:
			      bit4 = BIT4_X;
			      fprintf(stderr, "Unsupported bit value %d.\n",
			              bit);
			      assert(0);
			}
			vthread_put_bit(vpip_current_vthread,
					rfp->vbit+wdx+idx, bit4);

			aval >>= 1;
			bval >>= 1;
		  }
	    }
	    break;

	  default:
	    fprintf(stderr, "Unsupported format %d.\n", (int)vp->format);
	    assert(0);
      }

      return 0;
}

static vpiHandle sysfunc_put_real_value(vpiHandle ref, p_vpi_value vp, int)
{
      assert(ref->vpi_type->type_code == vpiSysFuncCall);

      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      rfp->put_value = true;

	/* Make sure this is a real valued function. */
      assert(rfp->vwid == -vpiRealConst);

      double val = 0.0;

      switch (vp->format) {

	  case vpiRealVal:
	    val = vp->value.real;
	    break;

	  default:
	    fprintf(stderr, "Unsupported format %d.\n", (int)vp->format);
	    assert(0);
      }

      vthread_put_real(vpip_current_vthread, rfp->vbit, val);
      return 0;
}

static vpiHandle sysfunc_put_4net_value(vpiHandle ref, p_vpi_value vp, int)
{
      assert(ref->vpi_type->type_code == vpiSysFuncCall);

      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      rfp->put_value = true;

      unsigned vwid = (unsigned) rfp->vwid;
      vvp_vector4_t val (vwid);

      switch (vp->format) {

          case vpiScalarVal: {
	        switch(vp->value.scalar) {
		      case vpi0:
			val.set_bit(0, BIT4_0);
                        break;
		      case vpi1:
                        val.set_bit(0, BIT4_1);
                        break;
		      case vpiX:
                        val.set_bit(0, BIT4_X);
                        break;
		      case vpiZ:
                        val.set_bit(0, BIT4_Z);
                        break;
		      default:
                        fprintf(stderr, "Unsupported bit value %d.\n",
                                (int)vp->value.scalar);
                        assert(0);
                }
          }

	  case vpiIntVal: {
		long tmp = vp->value.integer;
		for (unsigned idx = 0 ;  idx < vwid ;  idx += 1) {
		      val.set_bit(idx, (tmp&1)? BIT4_1 : BIT4_0);
		      tmp >>= 1;
		}
		break;
	  }

          case vpiTimeVal: {
                unsigned long tmp = vp->value.time->low;
                for (unsigned idx = 0 ;  idx < vwid ;  idx += 1) {
                      val.set_bit(idx, (tmp&1)? BIT4_1 : BIT4_0);

                      if (idx == 31)
                            tmp = vp->value.time->high;
                      else
                            tmp >>= 1;
                }
                break;
          }

	  case vpiVectorVal:

	    for (unsigned wdx = 0 ;  wdx < vwid ;  wdx += 32) {
		  unsigned word = wdx / 32;
		  unsigned long aval = vp->value.vector[word].aval;
		  unsigned long bval = vp->value.vector[word].bval;

		  for (unsigned idx = 0 ;  (wdx+idx) < vwid && idx < 32;
		       idx += 1) {
			int bit = (aval&1) | ((bval<<1)&2);
			vvp_bit4_t bit4;

			switch (bit) {
			    case 0:
			      bit4 = BIT4_0;
			      break;
			    case 1:
			      bit4 = BIT4_1;
			      break;
			    case 2:
			      bit4 = BIT4_Z;
			      break;
			    case 3:
			      bit4 = BIT4_X;
			      break;
			    default:
			      bit4 = BIT4_X;
			      fprintf(stderr, "Unsupported bit value %d.\n",
			              bit);
			      assert(0);
			}
			val.set_bit(wdx+idx, bit4);

			aval >>= 1;
			bval >>= 1;
		  }
	    }
	    break;

	  default:
	    fprintf(stderr, "XXXX format=%d, vwid=%u\n", (int)vp->format,
	            rfp->vwid);
	    assert(0);
      }

      rfp->fnet->send_vec4(val, vthread_get_wt_context());
      return 0;
}

static vpiHandle sysfunc_put_rnet_value(vpiHandle ref, p_vpi_value vp, int)
{
      assert(ref->vpi_type->type_code == vpiSysFuncCall);

      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      rfp->put_value = true;

      double val;
      switch (vp->format) {

	  case vpiRealVal:
	    val = vp->value.real;
	    break;

	  default:
	    val = 0.0;
	    fprintf(stderr, "Unsupported format %d.\n", (int)vp->format);
	    assert(0);
      }

      rfp->fnet->send_real(val, vthread_get_wt_context());

      return 0;
}

static vpiHandle sysfunc_put_no_value(vpiHandle ref, p_vpi_value, int)
{
      assert(ref->vpi_type->type_code == vpiSysFuncCall);

      return 0;
}


static const struct __vpirt vpip_sysfunc_rt = {
      vpiSysFuncCall,
      sysfunc_get,
      systask_get_str,
      0,
      sysfunc_put_value,
      systask_handle,
      systask_iter,
      0,
      0,
      0,
      0
};

static const struct __vpirt vpip_sysfunc_real_rt = {
      vpiSysFuncCall,
      sysfunc_get,
      systask_get_str,
      0,
      sysfunc_put_real_value,
      systask_handle,
      systask_iter,
      0,
      0,
      0,
      0
};

static const struct __vpirt vpip_sysfunc_4net_rt = {
      vpiSysFuncCall,
      sysfunc_get,
      systask_get_str,
      0,
      sysfunc_put_4net_value,
      systask_handle,
      systask_iter,
      0,
      0,
      0,
      0
};

static const struct __vpirt vpip_sysfunc_rnet_rt = {
      vpiSysFuncCall,
      sysfunc_get,
      systask_get_str,
      0,
      sysfunc_put_rnet_value,
      systask_handle,
      systask_iter,
      0,
      0,
      0,
      0
};

static const struct __vpirt vpip_sysfunc_no_rt = {
      vpiSysFuncCall,
      sysfunc_get,
      systask_get_str,
      0,
      sysfunc_put_no_value,
      systask_handle,
      systask_iter,
      0,
      0,
      0,
      0
};

  /* **** Manipulate the internal data structures. **** */

static struct __vpiUserSystf**def_table = 0;
static unsigned def_count = 0;

static struct __vpiUserSystf* allocate_def(void)
{
      if (def_table == 0) {
	    def_table = (struct __vpiUserSystf**)
		  malloc(sizeof (struct __vpiUserSystf*));

	    def_table[0] = (struct __vpiUserSystf*)
		  calloc(1, sizeof(struct __vpiUserSystf));

	    def_count = 1;
	    return def_table[0];
      }

      def_table = (struct __vpiUserSystf**)
	    realloc(def_table, (def_count+1)*sizeof (struct __vpiUserSystf*));

      def_table[def_count] = (struct __vpiUserSystf*)
	    calloc(1, sizeof(struct __vpiUserSystf));

      return def_table[def_count++];
}

#ifdef CHECK_WITH_VALGRIND
void def_table_delete(void)
{
      for (unsigned idx = 0; idx < def_count; idx += 1) {
	    free(const_cast<char *>(def_table[idx]->info.tfname));
	    free(def_table[idx]);
      }
      free(def_table);
      def_table = 0;
      def_count = 0;
}
#endif

struct __vpiSystfIterator {
      struct __vpiHandle base;
      unsigned next;
};

static vpiHandle systf_iterator_scan(vpiHandle ref, int)
{
      assert(ref->vpi_type->type_code == vpiIterator);
      struct __vpiSystfIterator*obj = (struct __vpiSystfIterator*) ref;

      if (obj->next >= def_count) {
	    vpi_free_object(ref);
	    return 0;
      }

      unsigned use_index = obj->next;
      while (!def_table[use_index]->is_user_defn) {
	    obj->next += 1;
	    use_index = obj->next;
	    if (obj->next >= def_count) {
		  vpi_free_object(ref);
		  return 0;
	    }
      }
      obj->next += 1;
      return &(def_table[use_index])->base;
}

static int systf_iterator_free_object(vpiHandle ref)
{
      assert(ref->vpi_type->type_code == vpiIterator);
      struct __vpiSystfIterator*obj = (struct __vpiSystfIterator*) ref;
      free(obj);
      return 1;
}

static const struct __vpirt vpip_systf_iterator_rt = {
      vpiIterator,
      0,
      0,
      0,
      0,
      0,
      0,
      systf_iterator_scan,
      systf_iterator_free_object,
      0,
      0
};

vpiHandle vpip_make_systf_iterator(void)
{
	/* Check to see if there are any user defined functions. */
      bool have_user_defn = false;
      unsigned idx;
      for (idx = 0; idx < def_count; idx += 1) {
	    if (def_table[idx]->is_user_defn) {
		  have_user_defn = true;
		  break;
	    }
      }
      if (!have_user_defn) return 0;

      struct __vpiSystfIterator*res;
      res = (struct __vpiSystfIterator*) calloc(1, sizeof (*res));
      res->base.vpi_type = &vpip_systf_iterator_rt;
      res->next = idx;
      return &res->base;
}

struct __vpiUserSystf* vpip_find_systf(const char*name)
{
      for (unsigned idx = 0 ;  idx < def_count ;  idx += 1)
	    if (strcmp(def_table[idx]->info.tfname, name) == 0)
		  return def_table[idx];

      return 0;
}

void vpip_make_systf_system_defined(vpiHandle ref)
{
      assert(ref);
      assert(ref->vpi_type->type_code == vpiUserSystf);
      struct __vpiUserSystf*obj = (__vpiUserSystf*) ref;
      obj->is_user_defn = false;
}

/*
 * To get better error message we need to cache the vpi_call fail
 * information so that we can print the file name.
 */
enum vpi_call_error_type {VPI_CALL_NO_DEF, VPI_CALL_TASK_AS_FUNC,
                          VPI_CALL_FUNC_AS_TASK, VPI_CALL_FUNC_AS_TASK_WARN};
typedef struct vpi_call_error {
      vpi_call_error_type type;
      char *name;
      long file_idx;
      long lineno;
} vpi_call_error_s, *vpi_call_error_p;

static vpi_call_error_p vpi_call_error_lst = NULL;
static unsigned vpi_call_error_num = 0;

static void add_vpi_call_error(vpi_call_error_type type, const char *name,
                               long file_idx, long lineno)
{
      vpi_call_error_lst = (vpi_call_error_p)
                            realloc((void *)vpi_call_error_lst,
                                    (vpi_call_error_num + 1) *
                                    sizeof(vpi_call_error_s));
      vpi_call_error_lst[vpi_call_error_num].type = type;
      vpi_call_error_lst[vpi_call_error_num].name = strdup(name);
      vpi_call_error_lst[vpi_call_error_num].file_idx = file_idx;
      vpi_call_error_lst[vpi_call_error_num].lineno = lineno;
      vpi_call_error_num += 1;
}

void print_vpi_call_errors()
{
      for (unsigned idx = 0; idx < vpi_call_error_num; idx += 1) {
	    switch (vpi_call_error_lst[idx].type) {
		case VPI_CALL_NO_DEF:
		  fprintf(stderr, "%s:%d: Error: System task/function %s() is "
		                  "not defined by any module.\n",
		                  file_names[vpi_call_error_lst[idx].file_idx],
		                  (int)vpi_call_error_lst[idx].lineno,
		                  vpi_call_error_lst[idx].name);
		  break;
		case VPI_CALL_TASK_AS_FUNC:
		  fprintf(stderr, "%s:%d: Error: %s() is a system task, it "
			          "cannot be called as a function.\n",
		                  file_names[vpi_call_error_lst[idx].file_idx],
		                  (int)vpi_call_error_lst[idx].lineno,
		                  vpi_call_error_lst[idx].name);
		  break;
		case VPI_CALL_FUNC_AS_TASK:
		  fprintf(stderr, "%s:%d: Error: %s() is a system function, it "
			          "cannot be called as a task.\n",
		                  file_names[vpi_call_error_lst[idx].file_idx],
		                  (int)vpi_call_error_lst[idx].lineno,
		                  vpi_call_error_lst[idx].name);
		  break;
		case VPI_CALL_FUNC_AS_TASK_WARN:
                 fprintf(stderr, "%s:%d: Warning: Calling system function "
                                 "%s() as a task.\n",
		                  file_names[vpi_call_error_lst[idx].file_idx],
		                  (int)vpi_call_error_lst[idx].lineno,
		                  vpi_call_error_lst[idx].name);
                 fprintf(stderr, "%s:%d:          The functions return "
                                 "value will be ignored.\n",
                                 file_names[vpi_call_error_lst[idx].file_idx],
                                 (int)vpi_call_error_lst[idx].lineno);
		  break;
	    }
	    free(vpi_call_error_lst[idx].name);
      }
      free(vpi_call_error_lst);
}

#ifdef CHECK_WITH_VALGRIND
static void cleanup_vpi_call_args(unsigned argc, vpiHandle*argv)
{
      if (argc) {
	    struct __vpiSysTaskCall*obj = new struct __vpiSysTaskCall;
	    obj->nargs = argc;
	    obj->args  = argv;
	    vpi_call_delete(&obj->base);
      }
}
#endif

/*
 * A vpi_call is actually built up into a vpiSysTaskCall VPI object
 * that refers back to the vpiUserSystf VPI object that is the
 * definition. So this function is called by the compiler when a
 * %vpi_call statement is encountered. Create here a vpiHandle that
 * describes the call, and return it. The %vpi_call instruction will
 * store this handle for when it is executed.
 *
 * If this is called to make a function, then the vwid will be a
 * non-zero value that represents the width or type of the result. The
 * vbit is also a non-zero value, the address in thread space of the result.
 */
vpiHandle vpip_build_vpi_call(const char*name, unsigned vbit, int vwid,
			      class vvp_net_t*fnet,
			      bool func_as_task_err, bool func_as_task_warn,
			      unsigned argc, vpiHandle*argv,
			      long file_idx, long lineno)
{
      assert(!(func_as_task_err && func_as_task_warn));

      struct __vpiUserSystf*defn = vpip_find_systf(name);
      if (defn == 0) {
	    add_vpi_call_error(VPI_CALL_NO_DEF, name, file_idx, lineno);
#ifdef CHECK_WITH_VALGRIND
	    cleanup_vpi_call_args(argc, argv);
#endif
	    return 0;
      }

      switch (defn->info.type) {
	  case vpiSysTask:
	    if (vwid != 0 || fnet != 0) {
		  add_vpi_call_error(VPI_CALL_TASK_AS_FUNC, name, file_idx,
		                     lineno);
#ifdef CHECK_WITH_VALGRIND
		  cleanup_vpi_call_args(argc, argv);
#endif
		  return 0;
	    }
	    assert(vbit == 0);
	    break;

	  case vpiSysFunc:
	    if (vwid == 0 && fnet == 0) {
		  if (func_as_task_err) {
			add_vpi_call_error(VPI_CALL_FUNC_AS_TASK,
			                   name, file_idx, lineno);
#ifdef CHECK_WITH_VALGRIND
			cleanup_vpi_call_args(argc, argv);
#endif
			return 0;
		  } else if (func_as_task_warn) {
			add_vpi_call_error(VPI_CALL_FUNC_AS_TASK_WARN,
			                   name, file_idx, lineno);
		  }
	    }
	    break;

	  default:
	    fprintf(stderr, "Unsupported vpi_call type %d.\n",
	                    (int)defn->info.type);
	    assert(0);
      }

      struct __vpiSysTaskCall*obj = new struct __vpiSysTaskCall;

      switch (defn->info.type) {
	  case vpiSysTask:
	    obj->base.vpi_type = &vpip_systask_rt;
	    break;

	  case vpiSysFunc:
	    if (fnet && vwid == -vpiRealConst) {
		  obj->base.vpi_type = &vpip_sysfunc_rnet_rt;

	    } else if (fnet && vwid > 0) {
		  obj->base.vpi_type = &vpip_sysfunc_4net_rt;

	    } else if (vwid == -vpiRealConst) {
		  obj->base.vpi_type = &vpip_sysfunc_real_rt;

	    } else if (vwid > 0) {
		  obj->base.vpi_type = &vpip_sysfunc_rt;

           } else if (vwid == 0 && fnet == 0) {
                 obj->base.vpi_type = &vpip_sysfunc_no_rt;

	    } else {
		  assert(0);
	    }
	    break;
      }

      obj->scope = vpip_peek_current_scope();
      obj->defn  = defn;
      obj->nargs = argc;
      obj->args  = argv;
      obj->vbit  = vbit;
      obj->vwid  = vwid;
      obj->fnet  = fnet;
      obj->file_idx  = (unsigned) file_idx;
      obj->lineno   = (unsigned) lineno;
      obj->userdata  = 0;
      obj->put_value = false;

      compile_compiletf(obj);

      return &obj->base;
}

#ifdef CHECK_WITH_VALGRIND
void vpi_call_delete(vpiHandle item)
{
      struct __vpiSysTaskCall*obj = (struct __vpiSysTaskCall *) item;
	/* The object can be NULL if there was an error. */
      if (!obj) return;
      for (unsigned arg = 0; arg < obj->nargs; arg += 1) {
	    switch (obj->args[arg]->vpi_type->type_code) {
		case vpiConstant:
		  switch (vpi_get(_vpiFromThr, obj->args[arg])) {
		      case _vpiNoThr:
			constant_delete(obj->args[arg]);
			break;
		      case _vpiVThr:
			thread_vthr_delete(obj->args[arg]);
			break;
		      case _vpiWord:
			thread_word_delete(obj->args[arg]);
			break;
		      default:
			assert(0);
		  }
		  break;
		case vpiMemoryWord:
		  if (vpi_get(_vpiFromThr, obj->args[arg]) == _vpi_at_A) {
			A_delete(obj->args[arg]);
		  }
		  break;
		case vpiPartSelect:
		  assert(vpi_get(_vpiFromThr, obj->args[arg]) == _vpi_at_PV);
		  PV_delete(obj->args[arg]);
		  break;
	    }
      }
      free(obj->args);
      delete obj;
}
#endif

/*
 * This function is used by the %vpi_call instruction to actually
 * place the call to the system task/function. For now, only support
 * calls to system tasks.
 */

vthread_t vpip_current_vthread;

void vpip_execute_vpi_call(vthread_t thr, vpiHandle ref)
{
      vpip_current_vthread = thr;

      assert((ref->vpi_type->type_code == vpiSysTaskCall)
	     || (ref->vpi_type->type_code == vpiSysFuncCall));

      vpip_cur_task = (struct __vpiSysTaskCall*)ref;

      if (vpip_cur_task->defn->info.calltf) {
	    assert(vpi_mode_flag == VPI_MODE_NONE);
	    vpi_mode_flag = VPI_MODE_CALLTF;
	    vpip_cur_task->put_value = false;
	    vpip_cur_task->defn->info.calltf(vpip_cur_task->defn->info.user_data);
	    vpi_mode_flag = VPI_MODE_NONE;
	      /* If the function call did not set a value then put a
	       * default value (0). */
	    if (ref->vpi_type->type_code == vpiSysFuncCall &&
	        !vpip_cur_task->put_value) {
		  s_vpi_value val;
		  if (vpip_cur_task->vwid == -vpiRealConst) {
			val.format = vpiRealVal;
			val.value.real = 0.0;
		  } else {
			val.format = vpiIntVal;
			val.value.integer = 0;
		  }
		  vpi_put_value(ref, &val, 0, vpiNoDelay);
	    }
      }
}

/*
 * This is the entry function that a VPI module uses to hook a new
 * task/function into the simulator. The function creates a new
 * __vpi_userSystf to represent the definition for the calls that come
 * to pass later.
 */
vpiHandle vpi_register_systf(const struct t_vpi_systf_data*ss)
{
      struct __vpiUserSystf*cur = allocate_def();
      assert(ss);
      switch (ss->type) {
	  case vpiSysTask:
	  case vpiSysFunc:
	    cur->base.vpi_type = &vpip_systf_def_rt;
	    break;
	  default:
	    fprintf(stderr, "Unsupported type %d.\n", (int)ss->type);
	    assert(0);
      }

      cur->info = *ss;
      cur->info.tfname = strdup(ss->tfname);
      cur->is_user_defn = true;

      return &cur->base;
}

PLI_INT32 vpi_put_userdata(vpiHandle ref, void*data)
{
      if (ref->vpi_type->type_code != vpiSysTaskCall
	  && ref->vpi_type->type_code != vpiSysFuncCall)
	    return 0;

      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;

      rfp->userdata = data;
      return 1;
}

void* vpi_get_userdata(vpiHandle ref)
{
      struct __vpiSysTaskCall*rfp = (struct __vpiSysTaskCall*)ref;
      assert((ref->vpi_type->type_code == vpiSysTaskCall)
	     || (ref->vpi_type->type_code == vpiSysFuncCall));

      return rfp->userdata;
}