172 lines
4.2 KiB
C++
172 lines
4.2 KiB
C++
/*
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* Copyright (c) 2000 Stephen Williams (steve@icarus.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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#ifdef HAVE_CVS_IDENT
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#ident "$Id: vvm_mux.cc,v 1.4 2002/08/12 01:35:07 steve Exp $"
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#endif
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# include "config.h"
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# include "vvm_gates.h"
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# include <assert.h>
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/*
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* The array of bits is arranged as:
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*
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* oooo ss 0000 1111 2222 3333 ...
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*
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*/
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vvm_mux::vvm_mux(unsigned w, unsigned s, unsigned sw)
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: width_(w), size_(s), selwid_(sw)
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{
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bits_ = new vpip_bit_t[width_*size_+selwid_+width_];
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out_ = new vvm_nexus::drive_t[width_];
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for (unsigned idx = 0 ; idx < width_*size_+selwid_+width_ ; idx += 1)
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bits_[idx] = StX;
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}
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vvm_mux::~vvm_mux()
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{
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delete[]out_;
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delete[]bits_;
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}
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vvm_nexus::drive_t* vvm_mux::config_rout(unsigned idx)
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{
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assert(idx < width_);
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return out_+idx;
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}
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unsigned vvm_mux::key_Sel(unsigned idx) const
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{
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assert(idx < selwid_);
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return idx + width_;
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}
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unsigned vvm_mux::key_Data(unsigned wi, unsigned si) const
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{
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assert(si < size_);
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assert(wi < width_);
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return width_ + selwid_ + si*width_ + wi;
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}
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void vvm_mux::init_Sel(unsigned idx, vpip_bit_t val)
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{
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assert(idx < selwid_);
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bits_[width_+idx] = val;
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}
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void vvm_mux::init_Data(unsigned idx, vpip_bit_t val)
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{
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assert(idx < width_*size_);
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bits_[width_+selwid_+idx] = val;
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}
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void vvm_mux::take_value(unsigned key, vpip_bit_t val)
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{
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if (bits_[key] == val)
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return;
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bits_[key] = val;
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evaluate_();
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}
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void vvm_mux::evaluate_()
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{
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vpip_bit_t*tmp = new vpip_bit_t[width_];
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vpip_bit_t*sel = bits_+width_;
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vpip_bit_t*inp = bits_+width_+selwid_;
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compute_mux(tmp, width_, sel, selwid_, inp, size_);
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for (unsigned idx = 0 ; idx < width_ ; idx += 1)
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if (tmp[idx] != bits_[idx]) {
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bits_[idx] = tmp[idx];
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out_[idx].set_value(bits_[idx]);
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}
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delete[]tmp;
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}
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void compute_mux(vpip_bit_t*out, unsigned wid,
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const vpip_bit_t*sel, unsigned swid,
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const vpip_bit_t*dat, unsigned size)
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{
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unsigned tmp = 0;
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for (unsigned idx = 0 ; idx < swid ; idx += 1) {
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if (B_ISXZ(sel[idx])) {
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tmp = size;
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break;
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}
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if (B_IS1(sel[idx]))
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tmp |= (1<<idx);
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}
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if (tmp >= size) {
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if (swid > 1) {
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for (unsigned idx = 0; idx < wid ; idx += 1)
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out[idx] = StX;
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} else {
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const unsigned b0 = 0;
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const unsigned b1 = wid;
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for (unsigned idx = 0 ; idx < wid ; idx += 1) {
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if (dat[idx+b0] == dat[idx+b1])
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out[idx] = dat[idx+b0];
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else
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out[idx] = StX;
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}
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}
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} else {
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unsigned b = tmp * wid;
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for (unsigned idx = 0; idx < wid ; idx += 1)
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out[idx] = dat[idx+b];
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}
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}
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/*
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* $Log: vvm_mux.cc,v $
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* Revision 1.4 2002/08/12 01:35:07 steve
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* conditional ident string using autoconfig.
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*
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* Revision 1.3 2001/07/25 03:10:50 steve
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* Create a config.h.in file to hold all the config
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* junk, and support gcc 3.0. (Stephan Boettcher)
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*
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* Revision 1.2 2000/03/22 04:26:41 steve
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* Replace the vpip_bit_t with a typedef and
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* define values for all the different bit
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* values, including strengths.
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*
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* Revision 1.1 2000/03/18 01:27:00 steve
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* Generate references into a table of nexus objects instead of
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* generating lots of isolated nexus objects. Easier on linkers
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* and compilers,
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*
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* Add missing nexus support for l-value bit selects,
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*
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* Detemplatize the vvm_mux type.
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*
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* Fix up the vvm_nexus destructor to disconnect from drivers.
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*
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*/
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