iverilog/vvp/vpi_signal.cc

/*
 * Copyright (c) 2001-2012 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
 */

/*
 * vpiReg handles are handled here. These objects represent vectors of
 * .var objects that can be manipulated by the VPI module.
 */

# include  "compile.h"
# include  "vpi_priv.h"
# include  "vvp_net_sig.h"
# include  "schedule.h"
# include  "statistics.h"
# include  "config.h"
#ifdef CHECK_WITH_VALGRIND
# include  "vvp_cleanup.h"
#endif
# include  <cmath>
# include  <iostream>
# include  <cstdio>
# include  <cstdlib>
# include  <climits>
# include  <cstring>
# include  <cassert>
#ifdef CHECK_WITH_VALGRIND
# include  <valgrind/memcheck.h>
#endif
# include  "ivl_alloc.h"

/*
 * Hex digits that represent 4-value bits of Verilog are not as
 * trivially obvious to display as if the bits were the usual 2-value
 * bits. So, although it is possible to write a function that
 * generates a correct character for 4*4-value bits, it is easier to
 * just perform the lookup in a table. This only takes 256 bytes,
 * which is not many executable instructions:-)
 *
 * The table is calculated at compile time, therefore, by the
 * draw_tt.c program.
 */
extern const char hex_digits[256];
extern const char oct_digits[64];

/*
 * The string values need a result buf to hold the results. This
 * buffer can be reused for that purpose. Whenever I have a need, the
 * need_result_buf function makes sure that need can be met.
 */
char *need_result_buf(unsigned cnt, vpi_rbuf_t type)
{
      static char*result_buf[2] = {0, 0};
      static size_t result_buf_size[2] = {0, 0};

      if (type == RBUF_DEL) {
	    free(result_buf[RBUF_VAL]);
	    result_buf[RBUF_VAL] = 0;
	    result_buf_size[RBUF_VAL] = 0;

	    free(result_buf[RBUF_STR]);
	    result_buf[RBUF_STR] = 0;
	    result_buf_size[RBUF_STR] = 0;

	    return 0;
      }

      cnt = (cnt + 0x0fff) & ~0x0fff;

      if (result_buf_size[type] == 0) {
	    result_buf[type] = (char*)malloc(cnt);
	    result_buf_size[type] = cnt;
      } else if (result_buf_size[type] < cnt) {
	    result_buf[type] = (char*)realloc(result_buf[type], cnt);
	    result_buf_size[type] = cnt;
      }

      return result_buf[type];
}

char *simple_set_rbuf_str(const char *s1)
{
      char *res = need_result_buf(strlen(s1)+1, RBUF_STR);
      if (res) strcpy(res,s1);
      return res;
}

char *generic_get_str(int code, vpiHandle ref, const char *name, const char *index)
{
      size_t len = strlen(name) + 1;  /* include space for null termination */
      char *bn = NULL;
      if (code == vpiFullName) {
	    bn = strdup(vpi_get_str(code,ref));
	    len += strlen(bn) + 1;  /* include space for "." separator */
      }
      if (index != NULL) len += strlen(index) + 2;  /* include space for brackets */

      char *res = need_result_buf(len, RBUF_STR);
      if (!res) {
	    free(bn);
	    return NULL;
      }
      *res=0;  /* start with nothing */

	/* if this works, I can make it more efficient later */
      if (bn != NULL) {
	    strcat(res, bn);
	    strcat(res, ".");
	    free(bn);
      }
      strcat(res, name);
      if (index != NULL) {
	    strcat(res, "[");
	    strcat(res, index);
	    strcat(res, "]");
      }
      return res;
}

static vpiHandle fill_in_net4(struct __vpiSignal*obj,
			      const char*name, int msb, int lsb,
			      bool signed_flag, vvp_net_t*node);

/*
 * The standard formating/conversion routines.
 * They work with full or partial signals.
 */

static void format_vpiBinStrVal(vvp_signal_value*sig, int base, unsigned wid,
                                s_vpi_value*vp)
{
      char *rbuf = need_result_buf(wid+1, RBUF_VAL);
      long end = base + (signed)wid;
      long offset = end - 1;
      long ssize = (signed)sig->value_size();

      for (long idx = base ;  idx < end ;  idx += 1) {
	    if (idx < 0 || idx >= ssize) {
                  rbuf[offset-idx] = 'x';
	    } else {
                  rbuf[offset-idx] = vvp_bit4_to_ascii(sig->value(idx));
	    }
      }
      rbuf[wid] = 0;

      vp->value.str = rbuf;
}

static void format_vpiOctStrVal(vvp_signal_value*sig, int base, unsigned wid,
                                s_vpi_value*vp)
{
      unsigned dwid = (wid + 2) / 3;
      char *rbuf = need_result_buf(dwid+1, RBUF_VAL);
      long end = base + (signed)wid;
      long ssize = (signed)sig->value_size();
      unsigned val = 0;

      rbuf[dwid] = 0;
      for (long idx = base ;  idx < end ;  idx += 1) {
	    unsigned bit = 0;
	    if (idx < 0 || idx >= ssize) {
                  bit = 2; // BIT4_X
	    } else {
                  switch (sig->value(idx)) {
		      case BIT4_0:
			bit = 0;
			break;
		      case BIT4_1:
			bit = 1;
			break;
		      case BIT4_X:
			bit = 2;
			break;
		      case BIT4_Z:
			bit = 3;
			break;
                  }
	    }
	    val |= bit << 2*((idx-base) % 3);

	    if ((idx-base) % 3 == 2) {
		dwid -= 1;
		rbuf[dwid] = oct_digits[val];
		val = 0;
	    }
      }

	/* Fill in X or Z if they are the only thing in the value. */
      switch (wid % 3) {
	  case 1:
	    if (val == 2) val = 42;
	    else if (val == 3) val = 63;
	    break;
	  case 2:
	    if (val == 10) val = 42;
	    else if (val == 15) val = 63;
	    break;
      }

      if (dwid > 0) rbuf[0] = oct_digits[val];

      vp->value.str = rbuf;
}

static void format_vpiHexStrVal(vvp_signal_value*sig, int base, unsigned wid,
                                s_vpi_value*vp)
{
      unsigned dwid = (wid + 3) / 4;
      char *rbuf = need_result_buf(dwid+1, RBUF_VAL);
      long end = base + (signed)wid;
      long ssize = (signed)sig->value_size();
      unsigned val = 0;

      rbuf[dwid] = 0;
      for (long idx = base ;  idx < end ;  idx += 1) {
	    unsigned bit = 0;
	    if (idx < 0 || idx >= ssize) {
                  bit = 2; // BIT4_X
	    } else {
                  switch (sig->value(idx)) {
		      case BIT4_0:
			bit = 0;
			break;
		      case BIT4_1:
			bit = 1;
			break;
		      case BIT4_X:
			bit = 2;
			break;
		      case BIT4_Z:
			bit = 3;
			break;
                  }
	    }
	    val |= bit << 2*((idx-base) % 4);

	    if ((idx-base) % 4 == 3) {
		dwid -= 1;
		rbuf[dwid] = hex_digits[val];
		val = 0;
	    }
      }

	/* Fill in X or Z if they are the only thing in the value. */
      switch (wid % 4) {
	  case 1:
	    if (val == 2) val = 170;
	    else if (val == 3) val = 255;
	    break;
	  case 2:
	    if (val == 10) val = 170;
	    else if (val == 15) val = 255;
	    break;
	  case 3:
	    if (val == 42) val = 170;
	    else if (val == 63) val = 255;
	    break;
      }

      if (dwid > 0) rbuf[0] = hex_digits[val];

      vp->value.str = rbuf;
}

static void format_vpiDecStrVal(vvp_signal_value*sig, int base, unsigned wid,
                                int signed_flag, s_vpi_value*vp)
{
      unsigned hwid = (sig->value_size()+2) / 3 + 1;
      char *rbuf = need_result_buf(hwid, RBUF_VAL);
      long ssize = (signed)sig->value_size();
      long end = base + (signed)wid;

	/* Do we have an end outside of the real signal vector. */
      if (base < 0 || end > ssize) {
	    bool all_x = true;
	    if (end > ssize) end = ssize;
	    if (base < 0) base = 0;
	    for (long idx = base ;  idx < end ;  idx += 1) {
		  if (sig->value(idx) != BIT4_X) {
			all_x = false;
			break;
		  }
	    }

	    if (all_x) {
		  rbuf[0] = 'x';
	    } else {
		  rbuf[0] = 'X';
	    }
	    rbuf[1] = 0;

	    vp->value.str = rbuf;
	    return;
      }

      vvp_vector4_t vec4;
      if (base == 0 && end == ssize) {
	    sig->vec4_value(vec4);
      } else {
	    vvp_vector4_t tmp;
	    sig->vec4_value(tmp);
	    vec4 = tmp.subvalue(base, wid);
      }

      vpip_vec4_to_dec_str(vec4, rbuf, hwid, signed_flag);

      vp->value.str = rbuf;
}

static void format_vpiIntVal(vvp_signal_value*sig, int base, unsigned wid,
                             int signed_flag, s_vpi_value*vp)
{
      vvp_vector4_t tmp;
      sig->vec4_value(tmp);
      vvp_vector4_t sub = tmp.subvalue(base, wid);
      long val = 0;
      vector4_to_value(sub, val, signed_flag, false);
      vp->value.integer = val;
}

static void format_vpiRealVal(vvp_signal_value*sig, int base, unsigned wid,
                              int signed_flag, s_vpi_value*vp)
{
      vvp_vector4_t vec4(wid);
      long ssize = (signed)sig->value_size();
      long end = base + (signed)wid;
      if (end > ssize) end = ssize;

      for (long idx = (base < 0) ? 0 : base ;  idx < end ;  idx += 1) {
	    vec4.set_bit(idx-base, sig->value(idx));
      }

      vp->value.real = 0.0;
      vector4_to_value(vec4, vp->value.real, signed_flag);
}

static void format_vpiStringVal(vvp_signal_value*sig, int base, unsigned wid,
                                s_vpi_value*vp)
{
      /* The result will use a character for each 8 bits of the
	 vector. Add one extra character for the highest bits that
	 don't form an 8 bit group. */
      char *rbuf = need_result_buf(wid/8 + ((wid&7)!=0) + 1, RBUF_VAL);
      char *cp = rbuf;

      char tmp = 0;
      for (long idx = base+(signed)wid-1; idx >= base; idx -= 1) {
	    tmp <<= 1;

	    if (idx >=0 && idx < (signed)sig->value_size() &&
	        sig->value(idx) == BIT4_1) {
		   tmp |= 1;
	    }

	    if (((idx-base)&7)==0){
		  /* Skip leading nulls. */
		  if (tmp == 0 && cp == rbuf)
			continue;

		  /* Nulls in the middle get turned into spaces. */
		  *cp++ = tmp ? tmp : ' ';
		  tmp = 0;
	    }
      }
      *cp++ = 0;

      vp->value.str = rbuf;
}

static void format_vpiScalarVal(vvp_signal_value*sig, int base,
                                s_vpi_value*vp)
{
      if (base >= 0 && base < (signed)sig->value_size()) {
	    switch (sig->value(base)) {
		case BIT4_0:
		  vp->value.scalar = vpi0;
		  break;
		case BIT4_1:
		  vp->value.scalar = vpi1;
		  break;
		case BIT4_X: {
		  vvp_scalar_t strn = sig->scalar_value(base);
		  if (strn.strength0() == 1) vp->value.scalar = vpiH;
		  else if (strn.strength1() == 1) vp->value.scalar = vpiL;
		  else vp->value.scalar = vpiX;
		  break;
		}
		case BIT4_Z:
		  vp->value.scalar = vpiZ;
		  break;
	    }
      } else {
	    vp->value.scalar = vpiX;
      }
}

static void format_vpiStrengthVal(vvp_signal_value*sig, int base,
                                  unsigned wid, s_vpi_value*vp)
{
      long end = base + (signed)wid;
      s_vpi_strengthval*op;

      op = (s_vpi_strengthval*)
	    need_result_buf(wid * sizeof(s_vpi_strengthval), RBUF_VAL);

      for (long idx = base ;  idx < end ;  idx += 1) {
	    if (idx >=0 && idx < (signed)sig->value_size()) {
		  vvp_scalar_t val = sig->scalar_value(idx);

		  /* vvp_scalar_t strengths are 0-7, but the vpi strength
		     is bit0-bit7. This gets the vpi form of the strengths
		     from the vvp_scalar_t strengths. */
		  unsigned s0 = 1 << val.strength0();
		  unsigned s1 = 1 << val.strength1();

		  switch (val.value()) {
		      case BIT4_0:
			op[idx-base].logic = vpi0;
			op[idx-base].s0 = s0|s1;
			op[idx-base].s1 = 0;
			break;

		      case BIT4_1:
			op[idx-base].logic = vpi1;
			op[idx-base].s0 = 0;
			op[idx-base].s1 = s0|s1;
			break;

		      case BIT4_X:
			op[idx-base].logic = vpiX;
			op[idx-base].s0 = s0;
			op[idx-base].s1 = s1;
			break;

		      case BIT4_Z:
			op[idx-base].logic = vpiZ;
			op[idx-base].s0 = vpiHiZ;
			op[idx-base].s1 = vpiHiZ;
			break;
		  }
	    } else {
		  op[idx-base].logic = vpiX;
		  op[idx-base].s0 = vpiStrongDrive;
		  op[idx-base].s1 = vpiStrongDrive;
	    }
      }

      vp->value.strength = op;
}

static void format_vpiVectorVal(vvp_signal_value*sig, int base, unsigned wid,
                                s_vpi_value*vp)
{
      long end = base + (signed)wid;
      unsigned int obit = 0;
      unsigned hwid = (wid + 31)/32;

      s_vpi_vecval *op = (p_vpi_vecval)
                         need_result_buf(hwid * sizeof(s_vpi_vecval), RBUF_VAL);
      vp->value.vector = op;

      op->aval = op->bval = 0;
      for (long idx = base ;  idx < end ;  idx += 1) {
	    if (base >= 0 && base < (signed)sig->value_size()) {
		switch (sig->value(idx)) {
		case BIT4_0:
		  op->aval &= ~(1 << obit);
		  op->bval &= ~(1 << obit);
		  break;
		case BIT4_1:
		  op->aval |= (1 << obit);
		  op->bval &= ~(1 << obit);
		  break;
		case BIT4_X:
		  op->aval |= (1 << obit);
		  op->bval |= (1 << obit);
		  break;
		case BIT4_Z:
		  op->aval &= ~(1 << obit);
		  op->bval |= (1 << obit);
		  break;
		}
	    } else {  /* BIT4_X */
		  op->aval |= (1 << obit);
		  op->bval |= (1 << obit);
	    }

	    obit++;
	    if (!(obit % 32)) {
		  op += 1;
		  if ((op - vp->value.vector) < (ptrdiff_t)hwid)
			op->aval = op->bval = 0;
		  obit = 0;
	    }
      }
}

/*
 * implement vpi_get for vpiReg objects.
 */
static int signal_get(int code, vpiHandle ref)
{
      struct __vpiSignal*rfp = dynamic_cast<__vpiSignal*>(ref);
      assert(rfp);

      switch (code) {
	  case vpiLineNo:
	    return 0;  // Not implemented for now!

	  case vpiSigned:
	    return rfp->signed_flag != 0;

	  case vpiArray:
	    return rfp->is_netarray != 0;

	  case vpiIndex: // This only works while we have a single index.
	    if (rfp->is_netarray) {
		  s_vpi_value vp;
		  vp.format = vpiIntVal;
		  vpi_get_value(rfp->id.index, &vp);
		  return vp.value.integer;
	    } else {
		  return vpiUndefined;
	    }

	  case vpiSize:
	    if (rfp->msb >= rfp->lsb)
		  return rfp->msb - rfp->lsb + 1;
	    else
		  return rfp->lsb - rfp->msb + 1;

	  case vpiNetType:
	    if (ref->get_type_code()==vpiNet)
		  return vpiWire;
	    else
		  return vpiUndefined;

	  case vpiLeftRange:
            return rfp->msb;

	  case vpiRightRange:
            return rfp->lsb;

          case vpiAutomatic:
            return (int) vpip_scope(rfp)->is_automatic;

	    // This private property must return zero when undefined.
	  case _vpiNexusId:
	    if (rfp->msb == rfp->lsb)
		  return (int) (unsigned long) rfp->node;
	    else
		  return 0;

	  default:
	    fprintf(stderr, "VPI error: unknown signal_get property %d.\n",
	            code);
	    return vpiUndefined;
      }
}

static char* signal_get_str(int code, vpiHandle ref)
{
      struct __vpiSignal*rfp = dynamic_cast<__vpiSignal*>(ref);
      assert(rfp);

      if (code == vpiFile) {  // Not implemented for now!
	    return simple_set_rbuf_str(file_names[0]);
      }

      if ((code != vpiName) && (code != vpiFullName)) return NULL;

      char *nm, *ixs;
      if (rfp->is_netarray) {
	    nm = strdup(vpi_get_str(vpiName, rfp->within.parent));
	    s_vpi_value vp;
	    vp.format = vpiDecStrVal;
	    vpi_get_value(rfp->id.index, &vp);
	    ixs = vp.value.str;  /* do I need to strdup() this? */
      } else {
	    nm = strdup(rfp->id.name);
	    ixs = NULL;
      }

	/* The scope information is added here for vpiFullName. */
      char *rbuf = generic_get_str(code, vpip_scope(rfp), nm, ixs);
      free(nm);
      return rbuf;
}

static vpiHandle signal_get_handle(int code, vpiHandle ref)
{
      struct __vpiSignal*rfp = dynamic_cast<__vpiSignal*>(ref);
      assert(rfp);

      switch (code) {

	  case vpiParent:
	    return rfp->is_netarray? rfp->within.parent : 0;

	  case vpiIndex:
	    return rfp->is_netarray? rfp->id.index : 0;

	  case vpiScope:
	    return vpip_scope(rfp);

	  case vpiModule:
	    return vpip_module(vpip_scope(rfp));
      }

      return 0;
}

static vpiHandle signal_iterate(int code, vpiHandle ref)
{
      struct __vpiSignal*rfp = dynamic_cast<__vpiSignal*>(ref);
      assert(rfp);

      if (code == vpiIndex) {
	    return rfp->is_netarray? array_index_iterate(code, rfp->id.index) : 0;
      }

      return 0;
}

static unsigned signal_width(const struct __vpiSignal*rfp)
{
      unsigned wid = (rfp->msb >= rfp->lsb)
	    ? (rfp->msb - rfp->lsb + 1)
	    : (rfp->lsb - rfp->msb + 1);

      return wid;
}

/*
 * The get_value method reads the values of the functors and returns
 * the vector to the caller. This causes no side-effect, and reads the
 * variables like a %load would.
 */
static void signal_get_value(vpiHandle ref, s_vpi_value*vp)
{
      struct __vpiSignal*rfp = dynamic_cast<__vpiSignal*>(ref);
      assert(rfp);

      unsigned wid = signal_width(rfp);

      vvp_signal_value*vsig = dynamic_cast<vvp_signal_value*>(rfp->node->fil);
      assert(vsig);

      switch (vp->format) {

	  case vpiIntVal:
	    format_vpiIntVal(vsig, 0, wid, rfp->signed_flag, vp);
	    break;

	  case vpiScalarVal:
	    format_vpiScalarVal(vsig, 0, vp);
	    break;

	  case vpiStrengthVal:
	    format_vpiStrengthVal(vsig, 0, wid, vp);
	    break;

	  case vpiBinStrVal:
	    format_vpiBinStrVal(vsig, 0, wid, vp);
	    break;

	  case vpiHexStrVal:
	    format_vpiHexStrVal(vsig, 0, wid, vp);
	    break;

	  case vpiOctStrVal:
	    format_vpiOctStrVal(vsig, 0, wid, vp);
	    break;

	  case vpiDecStrVal:
	    format_vpiDecStrVal(vsig, 0, wid, rfp->signed_flag, vp);
	    break;

	  case vpiStringVal:
	    format_vpiStringVal(vsig, 0, wid, vp);
	    break;

	  case vpiVectorVal:
	    format_vpiVectorVal(vsig, 0, wid, vp);
	    break;

	  case vpiRealVal:
	    format_vpiRealVal(vsig, 0, wid, rfp->signed_flag, vp);
	    break;

	  case vpiObjTypeVal:
	    if (wid == 1) {
		  vp->format = vpiScalarVal;
		  format_vpiScalarVal(vsig, 0, vp);
	    } else {
		  vp->format = vpiVectorVal;
		  format_vpiVectorVal(vsig, 0, wid, vp);
	    }
	    break;

	  default:
	    fprintf(stderr, "vvp internal error: get_value: "
		    "value type %d not implemented."
		    " Signal is %s in scope %s\n",
		    (int)vp->format, vpi_get_str(vpiName, ref),
		    vpip_scope(rfp)->name);
	    assert(0);
      }
}

/*
 * The put_value method writes the value into the vector, and returns
 * the affected ref. This operation works much like the %set or
 * %assign instructions and causes all the side-effects that the
 * equivalent instruction would cause.
 */

static vvp_vector4_t from_stringval(const char*str, unsigned wid)
{
      unsigned idx;
      const char*cp;

      cp = str + strlen(str);
      idx = 0;

      vvp_vector4_t val(wid, BIT4_0);

      while ((idx < wid) && (cp > str)) {
	    unsigned byte = *--cp;
	    int bit;

	    for (bit = 0 ;  bit < 8 ;  bit += 1) {
		  if (byte & 1)
			val.set_bit(idx, BIT4_1);

		  byte >>= 1;
		  idx += 1;
	    }
      }

      return val;
}

static vpiHandle signal_put_value(vpiHandle ref, s_vpi_value*vp, int flags)
{
      unsigned wid;
      struct __vpiSignal*rfp = dynamic_cast<__vpiSignal*>(ref);
      assert(rfp);

	/* If this is a release, then we are not really putting a
	   value. Instead, issue a release "command" to the signal
	   node to cause it to release a forced value. */
      if (flags == vpiReleaseFlag) {
	    vvp_net_fil_t*sig
		  = reinterpret_cast<vvp_net_fil_t*>(rfp->node->fil);
	    assert(sig);

	    vvp_net_ptr_t ptr(rfp->node, 0);
	    sig->release(ptr, false);
	    return ref;
      }

	/* Make a vvp_vector4_t vector to receive the translated value
	   that we are going to poke. This will get populated
	   differently depending on the format. */
      wid = (rfp->msb >= rfp->lsb)
	    ? (rfp->msb - rfp->lsb + 1)
	    : (rfp->lsb - rfp->msb + 1);


      vvp_vector4_t val = vec4_from_vpi_value(vp, wid);

	/* If this is a vpiForce, then instead of writing to the
	   signal input port, we write to the special "force" port. */
      int dest_port = 0;
      if (flags == vpiForceFlag)
	    dest_port = 2;

	/* This is the destination that I'm going to poke into. Make
	   it from the vvp_net_t pointer, and assume a write to
	   port-0. This is the port where signals receive input. */
      vvp_net_ptr_t destination (rfp->node, dest_port);

      vvp_send_vec4(destination, val, vthread_get_wt_context());

      return ref;
}

vvp_vector4_t vec4_from_vpi_value(s_vpi_value*vp, unsigned wid)
{
      vvp_vector4_t val (wid, BIT4_0);

      switch (vp->format) {

	  case vpiIntVal: {
		long vpi_val = vp->value.integer;
		for (unsigned idx = 0 ;  idx < wid ;  idx += 1) {
		      vvp_bit4_t bit = vpi_val&1 ? BIT4_1 : BIT4_0;
		      val.set_bit(idx, bit);
		      vpi_val >>= 1;
		}
		break;
	  }

	  case vpiVectorVal:
	    for (unsigned idx = 0 ;  idx < wid ;  idx += 1) {
		  unsigned long aval = vp->value.vector[idx/32].aval;
		  unsigned long bval = vp->value.vector[idx/32].bval;
		  aval >>= idx%32;
		  bval >>= idx%32;
		  int bitmask = (aval&1) | ((bval<<1)&2);
		  vvp_bit4_t bit = scalar_to_bit4(bitmask);
		  val.set_bit(idx, bit);
	    }
	    break;
	  case vpiBinStrVal:
	    vpip_bin_str_to_vec4(val, vp->value.str);
	    break;
	  case vpiOctStrVal:
	    vpip_oct_str_to_vec4(val, vp->value.str);
	    break;
	  case vpiDecStrVal:
	    vpip_dec_str_to_vec4(val, vp->value.str);
	    break;
	  case vpiHexStrVal:
	    vpip_hex_str_to_vec4(val, vp->value.str);
	    break;
	  case vpiScalarVal:
	    val.set_bit(0, scalar_to_bit4(vp->value.scalar));
	    break;
	  case vpiStringVal:
	    val = from_stringval(vp->value.str, wid);
	    break;
	  case vpiRealVal:
	    val = vvp_vector4_t(wid, vp->value.real);
	    break;

	  default:
	    fprintf(stderr, "vvp internal error: put_value: "
		    "value type %d not implemented here.\n",
		    (int)vp->format);
	    assert(0);

      }

      return val;
}

int __vpiSignal::vpi_get(int code)
{ return signal_get(code, this); }

char* __vpiSignal::vpi_get_str(int code)
{ return signal_get_str(code, this); }

void __vpiSignal::vpi_get_value(p_vpi_value val)
{ signal_get_value(this, val); }

vpiHandle __vpiSignal::vpi_put_value(p_vpi_value val, int flags)
{ return signal_put_value(this, val, flags); }

vpiHandle __vpiSignal::vpi_handle(int code)
{ return signal_get_handle(code, this); }

vpiHandle __vpiSignal::vpi_iterate(int code)
{ return signal_iterate(code, this); }

struct signal_reg : public __vpiSignal {
      inline signal_reg() { }
      int get_type_code(void) const { return vpiReg; }
};

struct signal_integer : public __vpiSignal {
      inline signal_integer() { }
      int get_type_code(void) const { return vpiIntegerVar; }
};

struct signal_net : public __vpiSignal {
      inline signal_net() { }
      int get_type_code(void) const { return vpiNet; }
};

struct signal_byte : public __vpiSignal {
      inline signal_byte() { }
      int get_type_code(void) const { return vpiByteVar; }
};

struct signal_bitvar : public __vpiSignal {
      inline signal_bitvar() { }
      int get_type_code(void) const { return vpiBitVar; }
};

struct signal_shortint : public __vpiSignal {
      inline signal_shortint() { }
      int get_type_code(void) const { return vpiShortIntVar; }
};

struct signal_int : public __vpiSignal {
      inline signal_int() { }
      int get_type_code(void) const { return vpiIntVar; }
};

struct signal_longint : public __vpiSignal {
      inline signal_longint() { }
      int get_type_code(void) const { return vpiLongIntVar; }
};


/*
 * Construct a vpiIntegerVar object. Indicate the type using a flag
 * to minimize the code modifications. Icarus implements integers
 * as 'reg signed [31:0]'.
 */
vpiHandle vpip_make_int4(const char*name, int msb, int lsb, vvp_net_t*vec)
{
      __vpiSignal*obj = new signal_integer;
      return fill_in_net4(obj, name, msb, lsb, true, vec);
}

/*
 * Construct the two-state SystemVerilog variables.
 */
vpiHandle vpip_make_int2(const char*name, int msb, int lsb, bool signed_flag,
                         vvp_net_t*vec)
{
      __vpiSignal*obj;

	// All unsigned 2-state variables are a vpiBitVar. All 2-state
	// variables with a non-zero lsb are also a vpiBitVar.
      if ((! signed_flag) || (lsb != 0) ) {
	    obj = new signal_bitvar;
      } else {
	      // These could also be bit declarations with matching
	      // information, but for now they get the apparent type.
	    switch (msb) {
		case 7:
		  obj = new signal_byte;
		  break;
		case 15:
		  obj = new signal_shortint;
		  break;
		case 31:
		  obj = new signal_int;
		  break;
		case 63:
		  obj = new signal_longint;
		  break;
		default:
		    // Every other type of bit vector is a vpiBitVar with
		    // array dimensions.
		  obj = new signal_bitvar;
		  break;
	    }
      }

      return fill_in_net4(obj, name, msb, lsb, signed_flag, vec);
}

/*
 * Construct a vpiReg/vpiLogicVar object. It's like a net, except for the type.
 */
vpiHandle vpip_make_var4(const char*name, int msb, int lsb,
			bool signed_flag, vvp_net_t*vec)
{
      __vpiSignal*obj = new signal_reg;
      return fill_in_net4(obj, name, msb, lsb, signed_flag, vec);
}

#ifdef CHECK_WITH_VALGRIND
static struct __vpiSignal **signal_pool = 0;
static unsigned signal_pool_count = 0;
static unsigned long signal_count = 0;
static unsigned long signal_dels = 0;
#endif

struct vpiSignal_plug {
      unsigned char space[sizeof (struct __vpiSignal)];
};

void* __vpiSignal::operator new(size_t siz)
{
      assert(siz == sizeof(struct vpiSignal_plug));
      static struct vpiSignal_plug*alloc_array = 0;
      static unsigned alloc_index = 0;
      const unsigned alloc_count = 512;

      if ((alloc_array == 0) || (alloc_index == alloc_count)) {
	    alloc_array = (struct vpiSignal_plug*)
		  calloc(alloc_count, sizeof(struct vpiSignal_plug));
	    alloc_index = 0;
#ifdef CHECK_WITH_VALGRIND
	    VALGRIND_MAKE_MEM_NOACCESS(alloc_array, alloc_count *
	                                            sizeof(struct vpiSignal_plug));
	    VALGRIND_CREATE_MEMPOOL(alloc_array, 0, 1);
	    signal_pool_count += 1;
	    signal_pool = (vpiSignal_plug **) realloc(signal_pool,
	                  signal_pool_count*sizeof(vpiSignal_plug **));
	    signal_pool[signal_pool_count-1] = alloc_array;
#endif
      }

      struct vpiSignal_plug*cur = alloc_array + alloc_index;
#ifdef CHECK_WITH_VALGRIND
      VALGRIND_MEMPOOL_ALLOC(alloc_array, cur, sizeof(struct vpiSignal_plug));
      cur->pool = alloc_array;
      signal_count += 1;
#endif
      alloc_index += 1;
      return cur;
}

void __vpiSignal::operator delete(void*)
{
      assert(0);
}

#ifdef CHECK_WITH_VALGRIND
void signal_delete(vpiHandle item)
{
      struct __vpiSignal *obj = (__vpiSignal *) item;
      assert(obj->node->fil);
      obj->node->fil->clear_all_callbacks();
      vvp_net_delete(obj->node);
      signal_dels += 1;
      VALGRIND_MEMPOOL_FREE(obj->pool, obj);
}

void signal_pool_delete()
{
      if (RUNNING_ON_VALGRIND && (signal_count != signal_dels)) {
	    fflush(NULL);
	    VALGRIND_PRINTF("Error: vvp missed deleting %ld of %lu signal(s).",
	                    (long) signal_count - signal_dels, signal_count);
      }

      for (unsigned idx = 0; idx < signal_pool_count; idx += 1) {
	    VALGRIND_DESTROY_MEMPOOL(signal_pool[idx]);
	    free(signal_pool[idx]);
      }

      free(signal_pool);
      signal_pool = 0;
      signal_pool_count = 0;
}
#endif

/*
 * Construct a vpiNet object. Give the object specified dimensions,
 * and point to the specified functor for the lsb.
 *
 * The name is the PLI name for the object. If it is an array it is
 * <name>[<index>].
 */
static vpiHandle fill_in_net4(struct __vpiSignal*obj,
			      const char*name, int msb, int lsb,
			      bool signed_flag, vvp_net_t*node)
{
      obj->id.name = name? vpip_name_string(name) : 0;
      obj->msb = msb;
      obj->lsb = lsb;
      obj->signed_flag = signed_flag? 1 : 0;
      obj->is_netarray = 0;
      obj->node = node;

	// Place this object within a scope. If this object is
	// attached to an array, then this value will be replaced with
	// the handle to the parent.
      obj->within.scope = vpip_peek_current_scope();

      count_vpi_nets += 1;

      return obj;
}

vpiHandle vpip_make_net4(const char*name, int msb, int lsb,
			 bool signed_flag, vvp_net_t*node)
{
      struct __vpiSignal*obj = new signal_net;
      return fill_in_net4(obj, name, msb, lsb, signed_flag, node);
}

static int PV_get_base(struct __vpiPV*rfp)
{
	/* We return from the symbol base if it is defined. */
      if (rfp->sbase != 0) {
	    s_vpi_value val;
	      /* Check to see if the value is defined. */
	    val.format = vpiVectorVal;
	    vpi_get_value(rfp->sbase, &val);
	    int words = (vpi_get(vpiSize, rfp->sbase)-1)/32 + 1;
	    for(int idx = 0; idx < words; idx += 1) {
		    /* Return INT_MIN to indicate an X base. */
		  if (val.value.vector[idx].bval != 0) return INT_MIN;
	    }
	      /* The value is defined so get and return it. */
	    val.format = vpiIntVal;
	    vpi_get_value(rfp->sbase, &val);
	    return val.value.integer;
      }

	/* If the width is zero then tbase is the constant. */
      if (rfp->twid == 0) return rfp->tbase;

	/* Get the value from thread space. */
      int tval = 0;
      for (unsigned idx = 0 ;  (idx < rfp->twid) && (idx < 8*sizeof(tval));
           idx += 1) {
	    vvp_bit4_t bit = vthread_get_bit(vpip_current_vthread,
                                             rfp->tbase + idx);
	    switch (bit) {
		case BIT4_X:
		case BIT4_Z:
		    /* We use INT_MIN to indicate an X base. */
		  return INT_MIN;
		  break;

		case BIT4_1:
		  tval |= 1<<idx;
		  break;

		case BIT4_0:
		  break; // Do nothing!
	    }
      }

	/* Check to see if we need to sign extend the result. */
      if (rfp->is_signed && (rfp->twid < 8*sizeof(tval))) {
	    vvp_bit4_t msb = vthread_get_bit(vpip_current_vthread,
	                                     rfp->tbase + rfp->twid - 1);
	    if (msb == BIT4_1) {
		  tval |= ~((1 << rfp->twid) - 1);
	    }
      }

      return tval;
}

static int PV_get(int code, vpiHandle ref)
{
      struct __vpiPV*rfp = dynamic_cast<__vpiPV*>(ref);
      assert(rfp);

      int rval = 0;
      switch (code) {
	case vpiLineNo:
	    return 0;  // Not implemented for now!

	case vpiSigned:
	    return 0;  // A part/bit select is always unsigned!

	case vpiSize:
	    return rfp->width;

	  /* This is like the &A<> in array.cc. */
	case vpiConstantSelect:
	    return rfp->sbase == 0 && rfp->twid == 0;

	case vpiLeftRange:
            rval += rfp->width - 1;
	case vpiRightRange:
	    rval += vpi_get(vpiRightRange, rfp->parent) + PV_get_base(rfp);
	    return rval;

        case vpiAutomatic:
            return vpi_get(vpiAutomatic, rfp->parent);

#ifdef CHECK_WITH_VALGRIND
        case _vpiFromThr:
            return _vpi_at_PV;
#endif

	default:
	    fprintf(stderr, "PV_get: property %d is unknown\n", code);
      }

      return 0;
}

static char* PV_get_str(int code, vpiHandle ref)
{
      struct __vpiPV*rfp = dynamic_cast<__vpiPV*>(ref);
      assert(rfp);

      switch (code) {
	case vpiFile:  // Not implemented for now!
	    return simple_set_rbuf_str(file_names[0]);

	case vpiName:
	case vpiFullName: {
	    const char*nm = vpi_get_str(code, rfp->parent);
	    size_t len = 256+strlen(nm);
	    char *full = (char *) malloc(len);
	    snprintf(full, len, "%s[%d:%d]", nm,
	                                     (int)vpi_get(vpiLeftRange, ref),
	                                     (int)vpi_get(vpiRightRange, ref));
	    full[len-1] = 0;
	    char *res = simple_set_rbuf_str(full);
	    free(full);
	    return res;
	}

	default:
	    fprintf(stderr, "PV_get_str: property %d is unknown.\n", code);
      }

      return 0;
}

static void PV_get_value(vpiHandle ref, p_vpi_value vp)
{
      struct __vpiPV*rfp = dynamic_cast<__vpiPV*>(ref);
      assert(rfp);

      vvp_signal_value*sig = dynamic_cast<vvp_signal_value*>(rfp->net->fil);
      assert(sig);

      switch (vp->format) {

	  case vpiIntVal:
	    format_vpiIntVal(sig, PV_get_base(rfp), rfp->width, 0, vp);
	    break;

	  case vpiBinStrVal:
	    format_vpiBinStrVal(sig, PV_get_base(rfp), rfp->width, vp);
	    break;

	  case vpiOctStrVal:
	    format_vpiOctStrVal(sig, PV_get_base(rfp), rfp->width, vp);
	    break;

	  case vpiHexStrVal:
	    format_vpiHexStrVal(sig, PV_get_base(rfp), rfp->width, vp);
	    break;

	  case vpiDecStrVal:
	    format_vpiDecStrVal(sig, PV_get_base(rfp), rfp->width, 0, vp);
	    break;

	  case vpiStringVal:
	    format_vpiStringVal(sig, PV_get_base(rfp), rfp->width, vp);
	    break;

	  case vpiScalarVal:
	    format_vpiScalarVal(sig, PV_get_base(rfp), vp);
	    break;

	  case vpiStrengthVal:
	    format_vpiStrengthVal(sig, PV_get_base(rfp), rfp->width, vp);
	    break;

	  case vpiVectorVal:
	    format_vpiVectorVal(sig, PV_get_base(rfp), rfp->width, vp);
	    break;

	  case vpiRealVal:
	    format_vpiRealVal(sig, PV_get_base(rfp), rfp->width, 0, vp);
	    break;

	  default:
	    fprintf(stderr, "vvp internal error: PV_get_value: "
		    "value type %d not implemented. Signal is %s.\n",
		    (int)vp->format, vpi_get_str(vpiFullName, rfp->parent));
	    assert(0);
      }
}

static vpiHandle PV_put_value(vpiHandle ref, p_vpi_value vp, int)
{
      struct __vpiPV*rfp = dynamic_cast<__vpiPV*>(ref);
      assert(rfp);
      vvp_signal_value*sig = dynamic_cast<vvp_signal_value*>(rfp->net->fil);
      assert(sig);

      unsigned sig_size = sig->value_size();
      unsigned width = rfp->width;
      int base = PV_get_base(rfp);
      if (base >= (signed) sig_size) return 0;
      if (base + (signed) width < 0) return 0;

      vvp_vector4_t val = vec4_from_vpi_value(vp, width);

	/*
	 * If the base is less than zero then trim off any unneeded
	 * lower bits.
	 */
      if (base < 0) {
	    width += base;
	    val = val.subvalue(-base, width);
	    base = 0;
      }

	/*
	 * If the value is wider than the signal then trim off any
	 * unneeded upper bits.
	 */
      if (base+width > sig_size) {
	    width = sig_size - base;
	    val = val.subvalue(0, width);
      }

      bool full_sig = base == 0 && width == sig_size;

      vvp_net_ptr_t dest(rfp->net, 0);

      if (full_sig) {
	    vvp_send_vec4(dest, val, vthread_get_wt_context());
      } else {
	    vvp_send_vec4_pv(dest, val, base, width, sig_size,
                             vthread_get_wt_context());
      }

      return 0;
}

static vpiHandle PV_get_handle(int code, vpiHandle ref)
{
      struct __vpiPV*rfp = dynamic_cast<__vpiPV*>(ref);
      assert(rfp);

      switch (code) {
	  case vpiParent:
	    return rfp->parent;

	  case vpiModule:
	    return vpi_handle(vpiModule, rfp->parent);
      }

      return 0;
}

inline __vpiPV::__vpiPV()
{ }

int __vpiPV::get_type_code(void) const
{ return vpiPartSelect; }

int __vpiPV::vpi_get(int code)
{ return PV_get(code, this); }

char* __vpiPV::vpi_get_str(int code)
{ return PV_get_str(code, this); }

void __vpiPV::vpi_get_value(p_vpi_value val)
{ PV_get_value(this, val); }

vpiHandle __vpiPV::vpi_put_value(p_vpi_value val, int flags)
{ return PV_put_value(this, val, flags); }

vpiHandle __vpiPV::vpi_handle(int code)
{ return PV_get_handle(code, this); }

vpiHandle vpip_make_PV(char*var, int base, int width)
{
      struct __vpiPV*obj = new __vpiPV;
      obj->parent = vvp_lookup_handle(var);
      obj->sbase = 0;
      obj->tbase = base;
      obj->twid = 0;
      obj->width = (unsigned) width;
      obj->net = 0;
      functor_ref_lookup(&obj->net, var);

      return obj;
}

vpiHandle vpip_make_PV(char*var, char*symbol, int width)
{
      struct __vpiPV*obj = new __vpiPV;
      obj->parent = vvp_lookup_handle(var);
      compile_vpi_lookup(&obj->sbase, symbol);
      obj->tbase = 0;
      obj->twid = 0;
      obj->width = (unsigned) width;
      obj->net = 0;
      functor_ref_lookup(&obj->net, var);

      return obj;
}

vpiHandle vpip_make_PV(char*var, vpiHandle handle, int width)
{
      struct __vpiPV*obj = new __vpiPV;
      obj->parent = vvp_lookup_handle(var);
      obj->sbase = handle;
      obj->tbase = 0;
      obj->twid = 0;
      obj->width = (unsigned) width;
      obj->net = 0;
      functor_ref_lookup(&obj->net, var);

      return obj;
}

vpiHandle vpip_make_PV(char*var, int tbase, int twid, char*is_signed, int width)
{
      struct __vpiPV*obj = new __vpiPV;
      obj->parent = vvp_lookup_handle(var);
      obj->sbase = 0;
      obj->tbase = tbase;
      obj->twid = (unsigned) twid;
      obj->is_signed = strcmp(is_signed, "s") == 0;
      obj->width = (unsigned) width;
      obj->net = 0;
      functor_ref_lookup(&obj->net, var);

      delete [] is_signed;

      return obj;
}

#ifdef CHECK_WITH_VALGRIND
void PV_delete(vpiHandle item)
{
      struct __vpiPV *obj = dynamic_cast<__vpiPV*>(item);
      if (obj->sbase) {
	    switch (obj->sbase->vpi_type->type_code) {
		case vpiMemoryWord:
		  if (vpi_get(_vpiFromThr, obj->sbase) == _vpi_at_A) {
			A_delete(obj->sbase);
		  }
		  break;
		case vpiPartSelect:
		  assert(vpi_get(_vpiFromThr, obj->sbase) == _vpi_at_PV);
		  PV_delete(obj->sbase);
		  break;
	    }
      }
      assert(obj->net->fil);
      obj->net->fil->clear_all_callbacks();
      delete obj;
}
#endif