127 lines
3.0 KiB
C++
127 lines
3.0 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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#if !defined(WINNT) && !defined(macintosh)
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#ident "$Id: vvm_add_sub.cc,v 1.2 2000/03/22 04:26:41 steve Exp $"
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#endif
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# include "vvm_gates.h"
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# include <assert.h>
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vvm_add_sub::vvm_add_sub(unsigned wid)
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: width_(wid), ndir_(St0)
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{
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ibits_ = new vpip_bit_t[width_*3];
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ro_ = new vvm_nexus::drive_t[width_];
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c_ = StX;
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for (unsigned idx = 0 ; idx < width_*3 ; idx += 1)
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ibits_[idx] = StX;
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}
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vvm_add_sub::~vvm_add_sub()
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{
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delete[]ro_;
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delete[]ibits_;
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}
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vvm_nexus::drive_t* vvm_add_sub::config_rout(unsigned idx)
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{
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assert(idx < width_);
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return ro_+idx;
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}
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vvm_nexus::drive_t* vvm_add_sub::config_cout()
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{
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return &co_;
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}
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unsigned vvm_add_sub::key_DataA(unsigned idx) const
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{
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assert(idx < width_);
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return idx;
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}
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unsigned vvm_add_sub::key_DataB(unsigned idx) const
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{
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assert(idx < width_);
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return idx+width_;
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}
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void vvm_add_sub::init_DataA(unsigned idx, vpip_bit_t val)
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{
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assert(idx < width_);
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ibits_[idx] = val;
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}
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void vvm_add_sub::init_DataB(unsigned idx, vpip_bit_t val)
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{
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assert(idx < width_);
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ibits_[width_+idx] = val;
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}
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void vvm_add_sub::init_Add_Sub(unsigned, vpip_bit_t val)
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{
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ndir_ = B_NOT(val);
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}
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void vvm_add_sub::start()
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{
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compute_();
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}
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void vvm_add_sub::take_value(unsigned key, vpip_bit_t val)
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{
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if (ibits_[key] == val) return;
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ibits_[key] = val;
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compute_();
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}
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void vvm_add_sub::compute_()
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{
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vpip_bit_t carry = ndir_;
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vpip_bit_t*a = ibits_;
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vpip_bit_t*b = ibits_+width_;
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vpip_bit_t*r = ibits_+2*width_;
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for (unsigned idx = 0 ; idx < width_ ; idx += 1) {
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vpip_bit_t val;
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val = add_with_carry(a[idx], B_XOR(b[idx],ndir_), carry);
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if (val == r[idx]) continue;
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r[idx] = val;
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vvm_event*ev = new vvm_out_event(val, ro_+idx);
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ev->schedule();
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}
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if (carry != c_)
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(new vvm_out_event(carry, &co_)) -> schedule();
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}
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/*
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* $Log: vvm_add_sub.cc,v $
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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 2000/03/17 17:25:53 steve
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* Adder and comparator in nexus style.
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*
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*/
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