102 lines
2.1 KiB
C++
102 lines
2.1 KiB
C++
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/*
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* Copyright (c) 1998 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)
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#ident "$Id: vvm_bit.cc,v 1.1 1998/11/09 23:44:10 steve Exp $"
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#endif
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# include "vvm.h"
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ostream& operator << (ostream&os, const vvm_bits_t&str)
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{
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os << str.get_width() << "b'";
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for (unsigned idx = str.get_width() ; idx > 0 ; idx -= 1)
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switch (str.get_bit(idx)) {
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case V0:
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os << "0";
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break;
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case V1:
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os << "1";
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break;
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case Vx:
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os << "x";
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break;
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case Vz:
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os << "z";
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break;
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}
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return os;
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}
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vvm_bits_t::~vvm_bits_t()
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{
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}
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vvm_bit_t add_with_carry(vvm_bit_t l, vvm_bit_t r, vvm_bit_t&carry)
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{
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unsigned li, ri, ci;
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switch (l) {
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case V0:
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li = 0;
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break;
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case V1:
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li = 1;
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break;
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default:
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carry = Vx;
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return Vx;
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}
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switch (r) {
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case V0:
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ri = 0;
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break;
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case V1:
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ri = 1;
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break;
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default:
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carry = Vx;
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return Vx;
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}
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switch (carry) {
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case V0:
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ci = 0;
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break;
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case V1:
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ci = 1;
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break;
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default:
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carry = Vx;
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return Vx;
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}
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unsigned sum = li + ri + ci;
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carry = (sum & 2)? V1 : V0;
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return (sum & 1)? V1 : V0;
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}
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/*
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* $Log: vvm_bit.cc,v $
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* Revision 1.1 1998/11/09 23:44:10 steve
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* Add vvm library.
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*
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*/
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