iverilog/vvm/vvm_gates.cc

/*
 * Copyright (c) 1999-2000 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
 */
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: vvm_gates.cc,v 1.9 2000/03/17 19:24:00 steve Exp $"
#endif

# include  "vvm_gates.h"

vvm_out_event::vvm_out_event(vpip_bit_t v, vvm_nexus::drive_t*o)
: output_(o), val_(v)
{
}

vvm_out_event::~vvm_out_event()
{
}

void vvm_out_event::event_function()
{
      output_->set_value(val_);
}

vvm_1bit_out::vvm_1bit_out(unsigned d)
: delay_(d)
{
}

vvm_1bit_out::~vvm_1bit_out()
{
}

void vvm_1bit_out::output(vpip_bit_t val)
{
      vvm_event*ev = new vvm_out_event(val, this);
      ev -> schedule(delay_);
}


vpip_bit_t compute_and(const vpip_bit_t*inp, unsigned count)
{
      vpip_bit_t outval = inp[0];
      for (unsigned i = 1 ;  i < count ;  i += 1)
	    outval = outval & inp[i];
      return outval;
}

vpip_bit_t compute_or(const vpip_bit_t*inp, unsigned count)
{
      vpip_bit_t outval = inp[0];
      for (unsigned i = 1 ;  i < count ;  i += 1)
	    outval = outval | inp[i];
      return outval;
}

vpip_bit_t compute_nor(const vpip_bit_t*inp, unsigned count)
{
      vpip_bit_t outval = inp[0];
      for (unsigned i = 1 ;  i < count ;  i += 1)
	    outval = outval | inp[i];
      return v_not(outval);
}

vpip_bit_t compute_xor(const vpip_bit_t*inp, unsigned count)
{
      vpip_bit_t outval = inp[0];
      for (unsigned i = 1; i < count; i++)
	    outval = outval ^ inp[i];
      return outval;
}

vpip_bit_t compute_nand(const vpip_bit_t*inp, unsigned count)
{
      return v_not(compute_and(inp,count));
}

vpip_bit_t compute_xnor(const vpip_bit_t*inp, unsigned count)
{
      return v_not(compute_xor(inp,count));
}

void compute_mux(vpip_bit_t*out, unsigned wid,
		 const vpip_bit_t*sel, unsigned swid,
		 const vpip_bit_t*dat, unsigned size)
{
      unsigned tmp = 0;
      for (unsigned idx = 0 ;  idx < swid ;  idx += 1)
	    switch (sel[idx]) {
		case V0:
		  break;
		case V1:
		  tmp |= (1<<idx);
		  break;
		default:
		  tmp = size;
		  break;
	    }

      if (tmp >= size) {

	    if (swid > 1) {
		  for (unsigned idx = 0; idx < wid ;  idx += 1)
			out[idx] = Vx;
	    } else {
		  const unsigned b0 = 0;
		  const unsigned b1 = wid;
		  for (unsigned idx = 0 ;  idx < wid ;  idx += 1) {
			if (dat[idx+b0] == dat[idx+b1])
			      out[idx] = dat[idx+b0];
			else
			      out[idx] = Vx;
		  }
	    }

      } else {
	    unsigned b = tmp * wid;
	    for (unsigned idx = 0; idx < wid ;  idx += 1)
		  out[idx] = dat[idx+b];
      }
}

vvm_and2::vvm_and2(unsigned long d)
: vvm_1bit_out(d)
{
}

vvm_and2::~vvm_and2()
{
}

void vvm_and2::init_I(unsigned idx, vpip_bit_t val)
{
      assert(idx < 2);
      input_[idx] = val;
}

void vvm_and2::start()
{
      output(input_[0] & input_[1]);
}

void vvm_and2::take_value(unsigned key, vpip_bit_t val)
{
      if (input_[key] == val)
	    return;

      input_[key] = val;
      output(input_[0] & input_[1]);
}


vvm_buf::vvm_buf(unsigned long d)
: vvm_1bit_out(d)
{
}

vvm_buf::~vvm_buf()
{
}

void vvm_buf::init_I(unsigned, vpip_bit_t)
{
}

void vvm_buf::take_value(unsigned, vpip_bit_t val)
{
      vpip_bit_t outval = val;
      if (val == Vz) outval = Vx;
      output(outval);
}

vvm_bufif1::vvm_bufif1(unsigned long d)
: vvm_1bit_out(d)
{
      input_[0] = Vx;
      input_[1] = Vx;
}

vvm_bufif1::~vvm_bufif1()
{
}

void vvm_bufif1::init_I(unsigned, vpip_bit_t)
{
}

void vvm_bufif1::take_value(unsigned key, vpip_bit_t val)
{
      if (input_[key] == val) return;
      input_[key] = val;

      if (input_[1] != V1) output(Vz);
      else if (input_[0] == Vz) output(Vx);
      else output(input_[0]);
}

vvm_eeq::vvm_eeq(unsigned long d)
: vvm_1bit_out(d)
{
}

vvm_eeq::~vvm_eeq()
{
}

void vvm_eeq::init_I(unsigned idx, vpip_bit_t val)
{
      input_[idx] = val;
}

void vvm_eeq::start()
{
      output(compute_());
}

void vvm_eeq::take_value(unsigned key, vpip_bit_t val)
{
      if (input_[key] == val)
	    return;
      input_[key] = val;
      output(compute_());
}

vpip_bit_t vvm_eeq::compute_() const
{
      vpip_bit_t outval = V0;
      if (input_[0] == input_[1])
	    outval = V1;
      return outval;
}

vvm_nor2::vvm_nor2(unsigned long d)
: vvm_1bit_out(d)
{
}

vvm_nor2::~vvm_nor2()
{
}

void vvm_nor2::init_I(unsigned idx, vpip_bit_t val)
{
      assert(idx < 2);
      input_[idx] = val;
}

void vvm_nor2::start()
{
      output(v_not(input_[0] | input_[1]));
}

void vvm_nor2::take_value(unsigned key, vpip_bit_t val)
{
      if (input_[key] == val)
	    return;

      input_[key] = val;
      output(v_not(input_[0] | input_[1]));
}

vvm_not::vvm_not(unsigned long d)
: vvm_1bit_out(d)
{
}

vvm_not::~vvm_not()
{
}

void vvm_not::init_I(unsigned, vpip_bit_t)
{
}

void vvm_not::start()
{
}

void vvm_not::take_value(unsigned, vpip_bit_t val)
{
      output(v_not(val));
}


/*
 * $Log: vvm_gates.cc,v $
 * Revision 1.9  2000/03/17 19:24:00  steve
 *  nor2 and and2 optimized gates.
 *
 * Revision 1.8  2000/03/17 03:36:07  steve
 *  Remove some useless template parameters.
 *
 * Revision 1.7  2000/03/16 19:03:04  steve
 *  Revise the VVM backend to use nexus objects so that
 *  drivers and resolution functions can be used, and
 *  the t-vvm module doesn't need to write a zillion
 *  output functions.
 *
 * Revision 1.6  2000/02/24 01:56:28  steve
 *  change not to v_not.
 *
 * Revision 1.5  2000/02/23 02:56:56  steve
 *  Macintosh compilers do not support ident.
 *
 * Revision 1.4  1999/12/12 19:47:54  steve
 *  Remove the useless vvm_simulation class.
 *
 * Revision 1.3  1999/12/02 04:54:11  steve
 *  Handle mux sel of X, if inputs are equal.
 *
 * Revision 1.2  1999/11/24 04:38:49  steve
 *  LT and GT fixes from Eric Aardoom.
 *
 * Revision 1.1  1999/11/22 00:30:52  steve
 *  Detemplate some and, or and nor methods.
 *
 */