/* Copyright (C) 1998-2003 T. Scott Dattalo This file is part of gpsim. gpsim is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. gpsim 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 gpsim; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #if !defined(__BIT_H__) #define __BIT_H__ // Function to test the Bit Class: extern void test_bits(); // Bit // // The Bit object is like a bool except that it supports 3-state // logic. class RegisterValue; class Bit { public: Bit(RegisterValue &rv, unsigned int bit_mask); Bit(bool nd=false, bool ni=false) : d(nd), i(ni) { } inline void operator = (const Bit &bv) { d = bv.d; i = bv.i; } inline bool operator == (const Bit &bv) const { return d==bv.d && i==bv.i; } inline void operator |= (const Bit &bv) { i = (i&bv.i) || (i&d) || (bv.d&bv.i); d |= bv.d; } inline void operator &= (const Bit &bv) { i = i&bv.i || (i&!bv.d) || (!d&bv.i); d &= bv.d; } inline void operator ^= (const Bit &bv) { d ^= bv.d; i &= bv.i; } inline Bit operator & (const Bit &r) { Bit bLv = *this; bLv.i = bLv.i&r.i || (r.i&!r.d) || (!bLv.d&bLv.i); bLv.d &= r.d; return bLv; } inline Bit operator | (const Bit &bv) { Bit bLv = *this; bLv |= bv; return bLv; } inline Bit operator ^ (const Bit &bv) { Bit bLv = *this; bLv ^= bv; return bLv; } inline bool isZero() { return d==false && i==true; } inline bool isOne() { return d==true && i==true; } inline bool isKnown() { return i==true; } inline bool isUnKnown() { return i==false; } inline void set(bool nd, bool ni) { d = nd; i = ni; } inline void clear() { d=false; i=true; } inline void set() { d = true; i = true; } inline void setUnknown() { i = false; } inline char val() { return !isKnown() ? '?' : (isOne() ? '1' : '0'); } friend Bit operator ! (Bit b); private: bool d; // The data bool i; // i=true if d is valid }; inline Bit operator ! (Bit b) { Bit bLv = b; bLv.d = !bLv.d; return bLv; } #endif