No need for nobufz.
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steve
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76
nobufz.cc
76
nobufz.cc
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@ -1,76 +0,0 @@
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/*
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* Copyright (c) 1998 Stephen Williams (steve@picturel.com)
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*
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* This source code is free software; you can redistribute it
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* and/or modify it in source code form under the terms of the GNU
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* General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#if !defined(WINNT) && !defined(macintosh)
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#ident "$Id: nobufz.cc,v 1.2 2000/02/23 02:56:55 steve Exp $"
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#endif
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/* NOBUFZ Function
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* This function transforms the netlist by removing BUFZ nodes that
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* have no obvious effect. The assumption here is that the BUFZ node
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* transmits information perfectly in one direction, and not at all in
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* the other.
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*
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* A BUFZ will *not* be eliminated if the output link is connected to
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* other outputs. The BUFZ protects its input link from the
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* double-driving on its output, so the bufz is not meaningless and
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* cannot be removed.
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*/
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# include "netlist.h"
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# include <assert.h>
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static bool is_a_bufz_node(const NetNode*obj)
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{
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return dynamic_cast<const NetBUFZ*>(obj);
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}
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void nobufz(Design*des)
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{
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des->clear_node_marks();
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while (NetNode*obj = des->find_node(&is_a_bufz_node)) {
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NetBUFZ*cur = dynamic_cast<NetBUFZ*>(obj);
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assert(cur);
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/* If there are more output pins on the output size of
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the BUFZ, then the BUFZ has a real effect (it
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protects its input side) and cannot be eliminated. */
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if (count_outputs(cur->pin(0)) == 1) {
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connect(cur->pin(0), cur->pin(1));
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delete cur;
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} else {
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cur->set_mark();
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}
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}
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}
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/*
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* $Log: nobufz.cc,v $
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* Revision 1.2 2000/02/23 02:56:55 steve
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* Macintosh compilers do not support ident.
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*
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* Revision 1.1 1998/12/02 04:37:13 steve
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* Add the nobufz function to eliminate bufz objects,
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* Object links are marked with direction,
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* constant propagation is more careful will wide links,
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* Signal folding is aware of attributes, and
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* the XNF target can dump UDP objects based on LCA
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* attributes.
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*
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*/
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35
vvm.txt
35
vvm.txt
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@ -7,25 +7,25 @@ the output program is self contained. It is useful to write a "main"
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module that tests a part being designed. This output type is most
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useful for batch simulation.
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Although none are required, these processing steps are recommended:
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nobufz
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nodangle
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propinit
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The iverilog target ``vvm'' generates code that uses the vvm library,
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and takes care of compiling the code into an executable program.
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So a sample command line to compile a Verilog file to C++ would be:
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The vvm library can also be used directly by C++ programmers if
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desired, ir order to skip the Verilog compilation step and write
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simulations in C++.
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ivl -F nobufz -F nodangle -F propinit -t vvm -o foo.cc foo.vl
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WRITING SIMULATIONS IN C++/VVM
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Once the program is compiled down to C++ code, it needs to be further
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compiled and linked into an executable image. The command for doing
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this is highly dependent on the system where you use Icarus
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Verilog. For Linux, the compile command is typically:
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It is possible to write simulations using C++ and the vvm library. The
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library classes fairly directly represent hardware devices and signal
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values, so writing such a simulation should be relatively obvious. The
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library also supports calling VPI modules written to work with Icarus
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Verilog. There are routines for loading and interfacing with VPI
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modules so that they think you are Verilog.
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c++ -rdynamic -o foo foo.cc -lvvm -ldl
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On any system, the compiled program requires that the VPI_MODULE_PATH
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be set to a ':' separated list of directories to search for vpi files,
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the system.vpi file in particular. This is a run time requirement.
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The details of the various classes are covered by comments in the
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various header files. The core header file is vvm.h, but the header
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files vvm_gates.h and vvm_signal.h are also important.
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NEXUS, GATES AND DRIVERS
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@ -151,8 +151,11 @@ bits are at:
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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$Id: vvm.txt,v 1.5 2000/03/16 19:03:04 steve Exp $
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$Id: vvm.txt,v 1.6 2000/05/11 01:44:52 steve Exp $
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$Log: vvm.txt,v $
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Revision 1.6 2000/05/11 01:44:52 steve
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No need for nobufz.
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Revision 1.5 2000/03/16 19:03:04 steve
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Revise the VVM backend to use nexus objects so that
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drivers and resolution functions can be used, and
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