// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Large 4-state numbers
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// Copyright 2003-2020 by Wilson Snyder. This program is free software; you
// can redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
//
//*************************************************************************

#include "config_build.h"
#include "verilatedos.h"

#include "V3Global.h"
#include "V3Number.h"
#include "V3Ast.h"

#include <algorithm>
#include <cerrno>
#include <cmath>
#include <cstdarg>
#include <iomanip>

#define MAX_SPRINTF_DOUBLE_SIZE 100  // Maximum characters with a sprintf %e/%f/%g (probably < 30)

// Number operations build output in-place so can't call e.g. foo.opX(foo)
#define NUM_ASSERT_OP_ARGS1(arg1)  \
    UASSERT((this != &(arg1)),  \
            "Number operation called with same source and dest");
#define NUM_ASSERT_OP_ARGS2(arg1, arg2)  \
    UASSERT((this != &(arg1) && this != &(arg2)),  \
            "Number operation called with same source and dest");
#define NUM_ASSERT_OP_ARGS3(arg1, arg2, arg3)  \
    UASSERT((this != &(arg1) && this != &(arg2) && this != &(arg3)),  \
            "Number operation called with same source and dest");

#define NUM_ASSERT_LOGIC_ARGS1(arg1)  \
    UASSERT((!(arg1).isDouble() && !(arg1).isString()), \
            "Number operation called with non-logic (double or string) argument: '"<<(arg1)<<'"');
#define NUM_ASSERT_LOGIC_ARGS2(arg1, arg2)  \
    NUM_ASSERT_LOGIC_ARGS1(arg1); NUM_ASSERT_LOGIC_ARGS1(arg2);

#define NUM_ASSERT_STRING_ARGS1(arg1)  \
    UASSERT((arg1).isString(), \
            "Number operation called with non-string argument: '"<<(arg1)<<'"');
#define NUM_ASSERT_STRING_ARGS2(arg1, arg2)  \
    NUM_ASSERT_STRING_ARGS1(arg1); NUM_ASSERT_STRING_ARGS1(arg2);

#define NUM_ASSERT_DOUBLE_ARGS1(arg1)  \
    UASSERT((arg1).isDouble(), \
            "Number operation called with non-double argument: '"<<(arg1)<<'"');
#define NUM_ASSERT_DOUBLE_ARGS2(arg1, arg2)  \
    NUM_ASSERT_DOUBLE_ARGS1(arg1); NUM_ASSERT_DOUBLE_ARGS1(arg2);

//======================================================================
// Errors

void V3Number::v3errorEnd(std::ostringstream& str) const {
    std::ostringstream nsstr;
    nsstr<<str.str();
    if (m_nodep) {
        m_nodep->v3errorEnd(nsstr);
    } else {
        m_fileline->v3errorEnd(nsstr);
    }
}

//======================================================================
// Read class functions
// CREATION

V3Number::V3Number(VerilogStringLiteral, AstNode* nodep, const string& str) {
    // Create a number using a verilog string as the value, thus 8 bits per character.
    // cppcheck bug - doesn't see init() resets these
    // cppcheck: Member variable 'm_sized/m_width' is not initialized in the constructor
    init(nodep, str.length()*8);
    m_fromString = true;
    for (unsigned pos=0; pos<str.length(); ++pos) {
        int topos = str.length()-1-pos;
        for (int bit=0; bit<8; ++bit) {
            if (str[pos] & (1UL<<bit)) {
                m_value[topos/4] |= (1UL<<(bit + (topos%4)*8));
            }
        }
    }
    opCleanThis(true);
}

void V3Number::V3NumberCreate(AstNode* nodep, const char* sourcep, FileLine* fl) {
    init(nodep, 0);
    m_fileline = fl;
    const char* value_startp = sourcep;
    for (const char* cp=sourcep; *cp; cp++) {
        if (*cp == '\'') {
            value_startp = cp+1;
            break;
        }
    }

    bool unbased = false;
    char base = '\0';
    if (value_startp != sourcep) {  // Has a '
        string widthn;
        const char* cp = sourcep;
        for (; *cp; cp++) {
            if (*cp == '\'') { cp++ ; break; }
            if (*cp != '_') widthn += *cp;
        }
        while (*cp == '_') cp++;
        if (*cp && tolower(*cp)=='s') {
            cp++; isSigned(true);
        }
        if (*cp) { base=*cp; cp++; }
        value_startp = cp;

        if (atoi(widthn.c_str())) {
            if (atoi(widthn.c_str()) < 0 || atoi(widthn.c_str()) > v3Global.opt.maxNumWidth()) {
                // atoi might convert large number to negative, so can't tell which
                v3error("Unsupported: Width of number exceeds implementation limit: "
                        << sourcep << "  (IEEE 1800-2017 6.9.1)");
                width(v3Global.opt.maxNumWidth(), true);
            } else {
                width(atoi(widthn.c_str()), true);
            }
        }
    } else {
        unbased = true;
        base = 'd';
    }

    for (int i = 0; i < words(); ++i) m_value[i] = m_valueX[i] = 0;

    // Special SystemVerilog unsized constructs
    if (base == '0') {
        setBit(0, 0); width(1, false);  // So we extend it
        m_autoExtend = true;
    } else if (base == '1') {
        setBit(0, 1); width(1, false);  // So we extend it
        m_autoExtend = true;
    } else if (tolower(base) == 'z') {
        setBit(0, 'z'); width(1, false);  // So we extend it
        m_autoExtend = true;
    } else if (tolower(base) == 'x') {
        setBit(0, 'x'); width(1, false);  // So we extend it
        m_autoExtend = true;
    }
    // Otherwise...
    else if (!m_sized) {
        width(32, false);  // Says IEEE 1800-2012 5.7.1
        if (unbased) isSigned(true);  // Also says the spec.
    }

    // Ignore leading blanks
    while (*value_startp=='_' || isspace(*value_startp)) value_startp++;
    if (!*value_startp && !m_autoExtend) {
        v3error("Number is missing value digits: "<<sourcep);
    }

    int obit = 0;  // Start at LSB
    if (tolower(base) == 'd') {
        // Ignore leading zeros so we don't issue too many digit errors when lots of leading 0's
        while (*value_startp=='_' || *value_startp=='0') value_startp++;
        // Convert decimal number to hex
        int olen = 0;
        uint32_t val = 0;
        int got_x = 0;
        int got_z = 0;
        int got_01 = 0;
        for (const char* cp=value_startp; *cp; cp++) {
            switch (tolower(*cp)) {
            case '0': case '1': case '2': case '3': case '4':
            case '5': case '6': case '7': case '8': case '9': {
                if (olen<=7) {  // 10000000 fits in 32 bits, so ok
                    // Constants are common, so for speed avoid wide math until we need it
                    val = val*10 + (*cp-'0');
                    m_value[0] = val;
                } else {  // Wide; all previous digits are already in m_value[0]
                    // this = (this * 10)/*product*/ + (*cp-'0')/*addend*/
                    // Assumed rare; lots of optimizations are possible here
                    V3Number product (this, width()+4);  // +4 for overflow detection
                    V3Number ten (this, width()+4, 10);
                    V3Number addend (this, width(), (*cp-'0'));
                    product.opMul(*this, ten);
                    this->opAdd(product, addend);
                    if (product.bitsValue(width(), 4)) {  // Overflowed
                        static int warned = 0;
                        v3error("Too many digits for "<<width()<<" bit number: "<<sourcep
                                <<std::endl
                                <<((!m_sized && !warned++)
                                   ? (V3Error::warnMore()+"... As that number was unsized"
                                      +" ('d...) it is limited to 32 bits (IEEE 1800-2017 5.7.1)\n"
                                      + V3Error::warnMore()+"... Suggest adding a size to it.")
                                   : ""));
                        while (*(cp+1)) cp++;  // Skip ahead so don't get multiple warnings
                    }
                }
                olen++;
                got_01 = 1;
                break;
            }
            case 'z': case '?': {
                got_z = 1;
                setAllBitsZ();
                break;
            }
            case 'x': {
                got_x = 1;
                setAllBitsX();
                break;
            }
            case '_': break;
            default: {
                v3error("Illegal character in decimal constant: "<<*cp);
                break;
            }
            }
        }
        obit = width();
        if ((got_01+got_x+got_z) > 1) {
            v3error("Mixing X/Z/? with digits not legal in decimal constant: "<<value_startp);
        }
    }
    else {
        // Convert bin/octal number to hex
        for (const char* cp=value_startp+strlen(value_startp)-1;
             cp >= value_startp;
             cp--) {
            if (*cp!='_' && *cp!='0' && obit>=width()) {
                v3error("Too many digits for "<<width()<<" bit number: "<<sourcep);
                break;
            }
            switch(tolower(base)) {
            case 'b': {
                switch(tolower(*cp)) {
                case '0': setBit(obit++, 0); break;
                case '1': setBit(obit++, 1); break;
                case 'z': case '?': setBit(obit++, 'z'); break;
                case 'x': setBit(obit++, 'x'); break;
                case '_': break;
                default:
                    v3error("Illegal character in binary constant: "<<*cp);
                }
            break;
            }

            case 'o':
            case 'c': {
                switch(tolower(*cp)) {
                case '0': setBit(obit++, 0); setBit(obit++, 0);  setBit(obit++, 0);  break;
                case '1': setBit(obit++, 1); setBit(obit++, 0);  setBit(obit++, 0);  break;
                case '2': setBit(obit++, 0); setBit(obit++, 1);  setBit(obit++, 0);  break;
                case '3': setBit(obit++, 1); setBit(obit++, 1);  setBit(obit++, 0);  break;
                case '4': setBit(obit++, 0); setBit(obit++, 0);  setBit(obit++, 1);  break;
                case '5': setBit(obit++, 1); setBit(obit++, 0);  setBit(obit++, 1);  break;
                case '6': setBit(obit++, 0); setBit(obit++, 1);  setBit(obit++, 1);  break;
                case '7': setBit(obit++, 1); setBit(obit++, 1);  setBit(obit++, 1);  break;
                case 'z': case '?':
                    setBit(obit++, 'z'); setBit(obit++, 'z');  setBit(obit++, 'z');  break;
                case 'x':
                    setBit(obit++, 'x'); setBit(obit++, 'x');  setBit(obit++, 'x');  break;
                case '_': break;
                default:
                    v3error("Illegal character in octal constant");
                }
                break;
            }

            case 'h': {
                switch(tolower(*cp)) {
                case '0': setBit(obit++,0); setBit(obit++,0); setBit(obit++,0); setBit(obit++,0); break;
                case '1': setBit(obit++,1); setBit(obit++,0); setBit(obit++,0); setBit(obit++,0); break;
                case '2': setBit(obit++,0); setBit(obit++,1); setBit(obit++,0); setBit(obit++,0); break;
                case '3': setBit(obit++,1); setBit(obit++,1); setBit(obit++,0); setBit(obit++,0); break;
                case '4': setBit(obit++,0); setBit(obit++,0); setBit(obit++,1); setBit(obit++,0); break;
                case '5': setBit(obit++,1); setBit(obit++,0); setBit(obit++,1); setBit(obit++,0); break;
                case '6': setBit(obit++,0); setBit(obit++,1); setBit(obit++,1); setBit(obit++,0); break;
                case '7': setBit(obit++,1); setBit(obit++,1); setBit(obit++,1); setBit(obit++,0); break;
                case '8': setBit(obit++,0); setBit(obit++,0); setBit(obit++,0); setBit(obit++,1); break;
                case '9': setBit(obit++,1); setBit(obit++,0); setBit(obit++,0); setBit(obit++,1); break;
                case 'a': setBit(obit++,0); setBit(obit++,1); setBit(obit++,0); setBit(obit++,1);  break;
                case 'b': setBit(obit++,1); setBit(obit++,1); setBit(obit++,0); setBit(obit++,1); break;
                case 'c': setBit(obit++,0); setBit(obit++,0); setBit(obit++,1); setBit(obit++,1); break;
                case 'd': setBit(obit++,1); setBit(obit++,0); setBit(obit++,1); setBit(obit++,1); break;
                case 'e': setBit(obit++,0); setBit(obit++,1); setBit(obit++,1); setBit(obit++,1); break;
                case 'f': setBit(obit++,1); setBit(obit++,1); setBit(obit++,1); setBit(obit++,1); break;
                case 'z': case '?':
                    setBit(obit++,'z'); setBit(obit++,'z'); setBit(obit++,'z'); setBit(obit++,'z'); break;
                case 'x':
                    setBit(obit++,'x'); setBit(obit++,'x'); setBit(obit++,'x'); setBit(obit++,'x'); break;
                case '_':  break;
                default:
                    v3error("Illegal character in hex constant: "<<*cp);
                }
                break;
            }
            default:
                v3error("Illegal base character: "<<base);
            }
        }
    }

    // Z or X extend specific width values.  Spec says we don't 1 extend.
    // This fixes 2'bx to become 2'bxx.
    while (obit<=width() && obit && bitIsXZ(obit-1)) {
        setBit(obit, bitIs(obit-1));
        obit++;
    }
    opCleanThis(true);

    //printf("Dump \"%s\"  CP \"%s\"  B '%c' %d W %d\n", sourcep, value_startp, base, width(), m_value[0]);
}

void V3Number::setNames(AstNode* nodep) {
    m_nodep = nodep;
    if (!nodep) return;
    m_fileline = nodep->fileline();
}

//======================================================================
// Global

int V3Number::log2b(uint32_t num) {
    // See also opCLog2
    for (int bit=31; bit>0; bit--) if (num & (VL_ULL(1)<<bit)) return bit;
    return 0;
}

//======================================================================
// Setters

V3Number& V3Number::setZero() {
    for (int i=0; i<words(); i++) m_value[i]=m_valueX[i] = 0;
    return *this;
}
V3Number& V3Number::setQuad(vluint64_t value) {
    for (int i=0; i<words(); i++) m_value[i]=m_valueX[i] = 0;
    m_value[0] = value & VL_ULL(0xffffffff);
    m_value[1] = (value>>VL_ULL(32)) & VL_ULL(0xffffffff);
    opCleanThis();
    return *this;
}
V3Number& V3Number::setLong(uint32_t value) {
    for (int i=0; i<words(); i++) m_value[i]=m_valueX[i] = 0;
    m_value[0] = value;
    opCleanThis();
    return *this;
}
V3Number& V3Number::setLongS(vlsint32_t value) {
    for (int i=0; i<words(); i++) m_value[i]=m_valueX[i] = 0;
    union { uint32_t u; vlsint32_t s; } u;
    u.s = value; if (u.s) { }
    m_value[0] = u.u;
    opCleanThis();
    return *this;
}
V3Number& V3Number::setDouble(double value) {
    if (VL_UNCOVERABLE(width()!=64)) {
        v3fatalSrc("Real operation on wrong sized number");
    }
    m_double = true;
    union { double d; uint32_t u[2]; } u;
    u.d = value; if (u.d != 0.0) { }
    for (int i=2; i<words(); i++) m_value[i]=m_valueX[i] = 0;
    m_value[0] = u.u[0]; m_value[1] = u.u[1];
    return *this;
}
V3Number& V3Number::setSingleBits(char value) {
    for (int i=1/*upper*/; i<words(); i++) m_value[i]=m_valueX[i] = 0;
    m_value[0] = (value=='1'||value=='x'||value==1||value==3);
    m_valueX[0] = (value=='z'||value=='x'||value==2||value==3);
    return *this;
}

V3Number& V3Number::setAllBits0() {
    for (int i=0; i<words(); i++) { m_value[i] = m_valueX[i]=0; }
    return *this;
}
V3Number& V3Number::setAllBits1() {
    for (int i=0; i<words(); i++) { m_value[i]= ~0; m_valueX[i] = 0; }
    opCleanThis();
    return *this;
}
V3Number& V3Number::setAllBitsX() {
    // Use setAllBitsXRemoved if calling this based on a non-X/Z input value such as divide by zero
    for (int i=0; i<words(); i++) { m_value[i]=m_valueX[i] = ~0; }
    opCleanThis();
    return *this;
}
V3Number& V3Number::setAllBitsZ() {
    for (int i=0; i<words(); i++) { m_value[i]=0; m_valueX[i] = ~0; }
    opCleanThis();
    return *this;
}
V3Number& V3Number::setAllBitsXRemoved() {
    if (!v3Global.constRemoveXs()) {
        return setAllBitsX();
    } else {
        // If we get a divide by zero we get Xs.
        // But after V3Unknown we have removed Xs, so use --x-assign to direct-insert 0/1
        if (v3Global.opt.xAssign() == "1") {
            return setAllBits1();
        } else {
            return setAllBits0();
        }
    }
}

V3Number& V3Number::setMask(int nbits) {
    setZero();
    for (int bit=0; bit<nbits; bit++) { setBit(bit, 1); }
    return *this;
}

//======================================================================
// ACCESSORS - as strings

string V3Number::ascii(bool prefixed, bool cleanVerilog) const {
    std::ostringstream out;

    if (isDouble()) {
        out.precision(17);
        if (width()!=64) out<<"%E-bad-width-double";
        else out<<toDouble();
        return out.str();
    } else if (isString()) {
        return '"'+toString()+'"';
    } else {
        if ((m_value[words()-1] | m_valueX[words()-1]) & ~hiWordMask()) out<<"%E-hidden-bits";
    }
    if (prefixed) {
        if (sized()) {
            out<<width()<<"'";
        } else if (autoExtend() && !sized() && width()==1) {
            out<<"'";
            if (bitIs0(0)) out<<'0';
            else if (bitIs1(0)) out<<'1';
            else if (bitIsZ(0)) out<<'z';
            else out<<'x';
            return out.str();
        } else {
            if (cleanVerilog) out<<"'";
            else out<<"?"<<width()<<"?";
        }
        if (isSigned()) out<<"s";
    }

    bool binary = (isFourState()
#ifdef V3NUMBER_ASCII_BINARY
                   || 1
#endif
        );
    //out<<"-"<<hex<<m_value[0]<<"-";

    // cppcheck-suppress konwnConditionTrueFalse
    if (binary) {
        out << "b";
        out << displayed("%0b");
    } else {
        if (prefixed) out << "h";
        // Always deal with 4 bits at once.  Note no 4-state, it's above.
        out << displayed("%0h");
    }
    return out.str();
}

bool V3Number::displayedFmtLegal(char format) {
    // Is this a valid format letter?
    switch (tolower(format)) {
    case 'b': return true;
    case 'c': return true;
    case 'd': return true;  // Unsigned decimal
    case 'e': return true;
    case 'f': return true;
    case 'g': return true;
    case 'h': return true;
    case 'o': return true;
    case 'p': return true;  // Pattern
    case 's': return true;
    case 't': return true;
    case 'u': return true;  // Packed 2-state
    case 'v': return true;  // Strength
    case 'x': return true;
    case 'z': return true;  // Packed 4-state
    case '@': return true;  // Packed string
    case '~': return true;  // Signed decimal
    default: return false;
    }
}

string V3Number::displayPad(size_t fmtsize, char pad, bool left, const string& in) {
    string padding;
    if (in.length() < fmtsize) padding = string(fmtsize - in.length(), pad);
    return left ? (in + padding) : (padding + in);
}

string V3Number::displayed(AstNode* nodep, const string& vformat) const {
    return displayed(nodep->fileline(), vformat);
}

string V3Number::displayed(FileLine* fl, const string& vformat) const {
    string::const_iterator pos = vformat.begin();
    UASSERT(pos != vformat.end() && pos[0]=='%',
            "$display-like function with non format argument "<<*this);
    ++pos;
    bool left = false;
    if (pos[0] == '-') {
        left = true;
        ++pos;
    }
    string fmtsize;
    for (; pos != vformat.end() && (isdigit(pos[0]) || pos[0]=='.'); ++pos) {
        fmtsize += pos[0];
    }
    string str;
    char code = tolower(pos[0]);
    switch (code) {
    case 'b': {
        int bit = width()-1;
        if (fmtsize == "0") while (bit && bitIs0(bit)) bit--;
        for (; bit>=0; bit--) {
            if (bitIs0(bit)) str+='0';
            else if (bitIs1(bit)) str+='1';
            else if (bitIsZ(bit)) str+='z';
            else str+='x';
        }
        return str;
    }
    case 'o': {
        int bit = width()-1;
        if (fmtsize == "0") while (bit && bitIs0(bit)) bit--;
        while ((bit%3)!=2) bit++;
        for (; bit>0; bit -= 3) {
            int v = bitsValue(bit-2, 3);
            str += static_cast<char>('0' + v);
        }
        return str;
    }
    case 'h':
    case 'x': {
        int bit = width()-1;
        if (fmtsize == "0") while (bit && bitIs0(bit)) bit--;
        while ((bit%4)!=3) bit++;
        for (; bit>0; bit -= 4) {
            int v = bitsValue(bit-3, 4);
            if (v>=10) str += static_cast<char>('a' + v - 10);
            else str += static_cast<char>('0' + v);
        }
        return str;
    }
    case 'c': {
        if (width()>8) fl->v3warn(WIDTH, "$display-like format of %c format of > 8 bit value");
        unsigned int v = bitsValue(0, 8);
        char strc[2]; strc[0] = v&0xff; strc[1] = '\0';
        str = strc;
        return str;
    }
    case 's': {
        // Spec says always drop leading zeros, this isn't quite right, we space pad.
        int bit = this->width()-1;
        bool start = true;
        while ((bit%8)!=7) bit++;
        for (; bit>=0; bit -= 8) {
            int v = bitsValue(bit-7, 8);
            if (!start || v) {
                str += static_cast<char>((v==0) ? ' ' : v);
                start = false;  // Drop leading 0s
            } else {
                if (fmtsize != "0") str += ' ';
            }
        }
        size_t fmtsizen = static_cast<size_t>(atoi(fmtsize.c_str()));
        str = displayPad(fmtsizen, ' ', left, str);
        return str;
    }
    case '~':  // Signed decimal
    case 't':  // Time
    case 'd': {  // Unsigned decimal
        bool issigned = (code == '~');
        if (fmtsize == "") {
            double mantissabits = this->width() - (issigned?1:0);
            double maxval = pow(2.0, mantissabits);
            double dchars = log10(maxval)+1.0;
            if (issigned) dchars++;  // space for sign
            fmtsize = cvtToStr(int(dchars));
        }
        if (issigned) {
            if (width() > 64) {
                str = toDecimalS();
            } else {
                str = cvtToStr(toSQuad());
            }
        } else {
            if (width() > 64) {
                str = toDecimalU();
            } else {
                str = cvtToStr(toUQuad());
            }
        }
        bool zeropad = fmtsize.length()>0 && fmtsize[0]=='0';
        // fmtsize might have changed since we parsed the %fmtsize
        size_t fmtsizen = static_cast<size_t>(atoi(fmtsize.c_str()));
        str = displayPad(fmtsizen, (zeropad ? '0' : ' '), left, str);
        return str;
    }
    case 'e':
    case 'f':
    case 'g':
    case '^': {  // Realtime
        char tmp[MAX_SPRINTF_DOUBLE_SIZE];
        sprintf(tmp, vformat.c_str(), toDouble());
        return tmp;
    }
    // 'l'   // Library - converted to text by V3LinkResolve
    // 'p'   // Packed - converted to another code by V3Width
    case 'u': {  // Packed 2-state
        for (int i=0; i<words(); i++) {
            str += static_cast<char>((m_value[i] >> 0) & 0xff);
            str += static_cast<char>((m_value[i] >> 8) & 0xff);
            str += static_cast<char>((m_value[i] >> 16) & 0xff);
            str += static_cast<char>((m_value[i] >> 24) & 0xff);
        }
        return str;
    }
    case 'z': {  // Packed 4-state
        for (int i=0; i<words(); i++) {
            str += static_cast<char>((m_value[i] >> 0) & 0xff);
            str += static_cast<char>((m_value[i] >> 8) & 0xff);
            str += static_cast<char>((m_value[i] >> 16) & 0xff);
            str += static_cast<char>((m_value[i] >> 24) & 0xff);
            str += static_cast<char>((m_valueX[i] >> 0) & 0xff);
            str += static_cast<char>((m_valueX[i] >> 8) & 0xff);
            str += static_cast<char>((m_valueX[i] >> 16) & 0xff);
            str += static_cast<char>((m_valueX[i] >> 24) & 0xff);
        }
        return str;
    }
    case 'v': {  // Strength
        int bit = width()-1;
        for (; bit>=0; bit--) {
            if (bitIs0(bit)) str += "St0 ";  // Yes, always a space even for bit 0
            else if (bitIs1(bit)) str += "St1 ";
            else if (bitIsZ(bit)) str += "StZ ";
            else str += "StX";
        }
        return str;
    }
    case '@': {  // Packed string
        size_t fmtsizen = static_cast<size_t>(atoi(fmtsize.c_str()));
        str = displayPad(fmtsizen, ' ', left, toString());
        return str;
    }
    default:
        fl->v3fatalSrc("Unknown $display-like format code for number: %"<<pos[0]);
        return "ERR";
    }
}

string V3Number::toDecimalS() const {
    if (isNegative()) {
        V3Number lhsNoSign = *this;
        lhsNoSign.opNegate(*this);
        return string("-") + lhsNoSign.toDecimalU();
    } else {
        return toDecimalU();
    }
}

string V3Number::toDecimalU() const {
    int maxdecwidth = (width()+3)*4/3;

    // Or (maxdecwidth+7)/8], but can't have more than 4 BCD bits per word
    V3Number bcd (this, maxdecwidth+4);
    V3Number tmp (this, maxdecwidth+4);
    V3Number tmp2 (this, maxdecwidth+4);

    int from_bit = width()-1;
    // Skip all leading zeros
    for (; from_bit >= 0 && bitIs0(from_bit); --from_bit);
    // Double-dabble algorithm
    for (; from_bit >= 0; --from_bit) {
        // Any digits >= 5 need an add 3 (via tmp)
        for (int nibble_bit = 0; nibble_bit < maxdecwidth; nibble_bit += 4) {
            if (bcd.bitsValue(nibble_bit, 4) >= 5) {
                tmp2.setAllBits0();
                tmp2.setBit(nibble_bit, 1);  // Add 3, decomposed as two bits
                tmp2.setBit(nibble_bit+1, 1);
                tmp.opAssign(bcd);
                bcd.opAdd(tmp, tmp2);
            }
        }
        // Shift; bcd = bcd << 1
        tmp.opAssign(bcd);
        bcd.opShiftL(tmp, V3Number(this, 32, 1));
        // bcd[0] = this[from_bit]
        if (bitIs1(from_bit)) bcd.setBit(0, 1);
    }

    string output;
    int lsb = (maxdecwidth-1) & ~3;
    for (; lsb>0; lsb-=4) {  // Skip leading zeros
        if (bcd.bitsValue(lsb, 4)) break;
    }
    for (; lsb>=0; lsb-=4) {
        output += ('0' + bcd.bitsValue(lsb, 4));  // 0..9
    }
    return output;
}

//======================================================================
// ACCESSORS - as numbers

uint32_t V3Number::toUInt() const {
    UASSERT(!isFourState(), "toUInt with 4-state "<<*this);
    // We allow wide numbers that represent values <= 32 bits
    for (int i=1; i<words(); ++i) {
        if (m_value[i]) {
            v3error("Value too wide for 32-bits expected in this context "<<*this);
            break;
        }
    }
    return m_value[0];
}

double V3Number::toDouble() const {
    if (VL_UNCOVERABLE(!isDouble() || width()!=64)) {
        v3fatalSrc("Real operation on wrong sized/non-real number");
    }
    union { double d; uint32_t u[2]; } u;
    u.u[0] = m_value[0]; u.u[1] = m_value[1];
    return u.d;
}

vlsint32_t V3Number::toSInt() const {
    if (isSigned()) {
        uint32_t v = toUInt();
        uint32_t signExtend = (-(v & (1UL<<(width()-1))));
        uint32_t extended = v | signExtend;
        return static_cast<vlsint32_t>(extended);
    } else {
        // Where we use this (widths, etc) and care about signedness,
        // we can reasonably assume the MSB isn't set on unsigned numbers.
        return static_cast<vlsint32_t>(toUInt());
    }
}

vluint64_t V3Number::toUQuad() const {
    UASSERT(!isFourState(), "toUQuad with 4-state "<<*this);
    // We allow wide numbers that represent values <= 64 bits
    if (isDouble()) return static_cast<vluint64_t>(toDouble());
    for (int i=2; i<words(); ++i) {
        if (m_value[i]) {
            v3error("Value too wide for 64-bits expected in this context "<<*this);
            break;
        }
    }
    if (width()<=32) return (static_cast<vluint64_t>(toUInt()));
    return ((static_cast<vluint64_t>(m_value[1])<<VL_ULL(32))
            | (static_cast<vluint64_t>(m_value[0])));
}

vlsint64_t V3Number::toSQuad() const {
    if (isDouble()) return static_cast<vlsint64_t>(toDouble());
    vluint64_t v = toUQuad();
    vluint64_t signExtend = (-(v & (VL_ULL(1)<<(width()-1))));
    vluint64_t extended = v | signExtend;
    return static_cast<vlsint64_t>(extended);
}

string V3Number::toString() const {
    UASSERT(!isFourState(), "toString with 4-state "<<*this);
    // Spec says always drop leading zeros, this isn't quite right, we space pad.
    if (isString()) return m_stringVal;
    int bit = this->width()-1;
    bool start = true;
    while ((bit%8)!=7) bit++;
    string str;
    for (; bit>=0; bit -= 8) {
        int v = bitsValue(bit-7, 8);
        if (!start || v) {
            str += static_cast<char>((v==0) ? ' ' : v);
            start = false;  // Drop leading 0s
        }
    }
    return str;
}

uint32_t V3Number::toHash() const {
    return m_value[0];
}

uint32_t V3Number::edataWord(int eword) const {
    UASSERT(!isFourState(), "edataWord with 4-state "<<*this);
    return m_value[eword];
}

uint8_t V3Number::dataByte(int byte) const {
    return (edataWord(byte / (VL_EDATASIZE / 8)) >> ((byte * 8) % VL_EDATASIZE)) & 0xff;
}

bool V3Number::isEqZero() const {
    for (int i=0; i<words(); i++) {
        if (m_value[i] || m_valueX[i]) return false;
    }
    return true;
}
bool V3Number::isNeqZero() const {
    for (int i=0; i<words(); i++) {
        if (m_value[i] & ~m_valueX[i]) return true;
    }
    return false;
}
bool V3Number::isBitsZero(int msb, int lsb) const {
    for (int i=lsb; i<=msb; i++) {
        if (VL_UNLIKELY(!bitIs0(i))) return false;
    }
    return true;
}
bool V3Number::isEqOne() const {
    if (m_value[0]!=1 || m_valueX[0]) return false;
    for (int i=1; i<words(); i++) {
        if (m_value[i] || m_valueX[i]) return false;
    }
    return true;
}
bool V3Number::isEqAllOnes(int optwidth) const {
    if (!optwidth) optwidth = width();
    for (int bit=0; bit<optwidth; bit++) {
        if (!bitIs1(bit)) return false;
    }
    return true;
}
bool V3Number::isFourState() const {
    if (isDouble() || isString()) return false;
    for (int i=0; i < words(); ++i) {
        if (m_valueX[i]) return true;
    }
    return false;
}
bool V3Number::isUnknown() const {
    if (isDouble() || isString()) return false;
    for (int bit=0; bit<width(); bit++) {
        if (bitIsX(bit)) return true;
    }
    return false;
}
bool V3Number::isLt(const V3Number& rhs) const {
    for (int bit=0; bit < std::max(this->width(), rhs.width()); bit++) {
        if (this->bitIs1(bit) && rhs.bitIs0(bit)) { return 1; }
        if (rhs.bitIs1(bit) && this->bitIs0(bit)) { return 0; }
        if (this->bitIsXZ(bit)) { return 0; }
        if (rhs.bitIsXZ(bit)) { return 0; }
    }
    return 0;
}
bool V3Number::isLtXZ(const V3Number& rhs) const {
    // Include X/Z in comparisons for sort ordering
    for (int bit=0; bit < std::max(this->width(), rhs.width()); bit++) {
        if (this->bitIs1(bit) && rhs.bitIs0(bit)) { return 1; }
        if (rhs.bitIs1(bit) && this->bitIs0(bit)) { return 0; }
        if (this->bitIsXZ(bit)) { return 1; }
        if (rhs.bitIsXZ(bit)) { return 0; }
    }
    return 0;
}

int V3Number::widthMin() const {
    for (int bit=width()-1; bit>0; bit--) {
        if (!bitIs0(bit)) return bit+1;
    }
    return 1;  // one bit even if number is == 0
}

uint32_t V3Number::countOnes() const {
    int n = 0;
    for (int bit=0; bit<this->width(); bit++) {
        if (bitIs1(bit)) n++;
    }
    return n;
}

uint32_t V3Number::mostSetBitP1() const {
    for (int bit=this->width()-1; bit>=0; bit--) {
        if (bitIs1(bit)) return bit+1;
    }
    return 0;
}
//======================================================================

V3Number& V3Number::opBitsNonX(const V3Number& lhs) {  // 0/1->1, X/Z->0
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs0(bit) || lhs.bitIs1(bit))  { setBit(bit, 1); }
    }
    return *this;
}
V3Number& V3Number::opBitsOne(const V3Number& lhs) {  // 1->1, 0/X/Z->0
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs1(bit))  { setBit(bit, 1); }
    }
    return *this;
}
V3Number& V3Number::opBitsXZ(const V3Number& lhs) {  // 0/1->1, X/Z->0
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIsXZ(bit))  { setBit(bit, 1); }
    }
    return *this;
}
V3Number& V3Number::opBitsZ(const V3Number& lhs) {  // 0/1->1, X/Z->0
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
      if (lhs.bitIsZ(bit))  { setBit(bit, 1); }
    }
    return *this;
}
V3Number& V3Number::opBitsNonZ(const V3Number& lhs) {  // 0/1->1, X/Z->0
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
      if (!lhs.bitIsZ(bit)) { setBit(bit, 1); }
    }
    return *this;
}

//======================================================================
// Operators - Simple per-bit logical ops

V3Number& V3Number::opRedOr(const V3Number& lhs) {
    // op i, 1 bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    char outc = 0;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs1(bit)) return setSingleBits(1);
        else if (lhs.bitIs0(bit)) ;
        else outc = 'x';
    }
    return setSingleBits(outc);
}

V3Number& V3Number::opRedAnd(const V3Number& lhs) {
    // op i, 1 bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    char outc = 1;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs0(bit)) return setSingleBits(0);
        else if (lhs.bitIs1(bit)) ;
        else outc = 'x';
    }
    return setSingleBits(outc);
}

V3Number& V3Number::opRedXor(const V3Number& lhs) {
    // op i, 1 bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    char outc = 0;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs1(bit)) { if (outc==1) outc = 0; else if (outc==0) outc = 1; }
        else if (lhs.bitIs0(bit)) ;
        else outc = 'x';
    }
    return setSingleBits(outc);
}

V3Number& V3Number::opRedXnor(const V3Number& lhs) {
    // op i, 1 bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    char outc = 1;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs1(bit)) { if (outc==1) outc = 0; else if (outc==0) outc = 1; }
        else if (lhs.bitIs0(bit)) ;
        else outc = 'x';
    }
    return setSingleBits(outc);
}

V3Number& V3Number::opCountOnes(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    if (lhs.isFourState()) return setAllBitsX();
    setZero();
    m_value[0] = lhs.countOnes();
    opCleanThis();
    return *this;
}
V3Number& V3Number::opIsUnknown(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    return setSingleBits(lhs.isUnknown());
}
V3Number& V3Number::opOneHot(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    if (lhs.isFourState()) return setAllBitsX();
    return setSingleBits(lhs.countOnes()==1);
}
V3Number& V3Number::opOneHot0(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    if (lhs.isFourState()) return setAllBitsX();
    return setSingleBits(lhs.countOnes()<=1);
}
V3Number& V3Number::opCLog2(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    if (lhs.isFourState()) return setAllBitsX();
    // IE if 4, this algorithm didn't pre-subtract 1, so we need to post-correct now
    int adjust = (lhs.countOnes()==1) ? 0 : 1;
    for (int bit=lhs.width()-1; bit>=0; bit--) {
        if (lhs.bitIs1(bit)) {
            setLong(bit+adjust);
            return *this;
        }
    }
    setZero();
    return *this;
}

V3Number& V3Number::opLogNot(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    // op i, 1 bit return
    char outc = 1;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs1(bit)) { outc=0; goto last;}
        else if (lhs.bitIs0(bit)) ;
        else outc = 'x';
    }
  last:
    return setSingleBits(outc);
}

V3Number& V3Number::opNot(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    // op i, L(lhs) bit return
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs0(bit))       { setBit(bit, 1); }
        else if (lhs.bitIsXZ(bit)) { setBit(bit,'x'); }
    }
    return *this;
}

V3Number& V3Number::opAnd(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    // i op j, max(L(lhs),L(rhs)) bit return, careful need to X/Z extend.
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs1(bit) && rhs.bitIs1(bit))  { setBit(bit, 1); }
        else if (lhs.bitIs0(bit) || rhs.bitIs0(bit)) ;  // 0
        else { setBit(bit,'x'); }
    }
    return *this;
}

V3Number& V3Number::opOr(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    // i op j, max(L(lhs),L(rhs)) bit return, careful need to X/Z extend.
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs1(bit) || rhs.bitIs1(bit))  { setBit(bit, 1); }
        else if (lhs.bitIs0(bit) && rhs.bitIs0(bit)) ;  // 0
        else { setBit(bit,'x'); }
    }
    return *this;
}

V3Number& V3Number::opChangeXor(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    // 32 bit result
    opEq(lhs, rhs);
    return *this;
}

V3Number& V3Number::opXor(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs1(bit) && rhs.bitIs0(bit))  { setBit(bit, 1); }
        else if (lhs.bitIs0(bit) && rhs.bitIs1(bit))  { setBit(bit, 1); }
        else if (lhs.bitIsXZ(bit) && rhs.bitIsXZ(bit)) { setBit(bit,'x'); }
        // else zero
    }
    return *this;
}

V3Number& V3Number::opXnor(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (lhs.bitIs1(bit) && rhs.bitIs1(bit))  { setBit(bit, 1); }
        else if (lhs.bitIs0(bit) && rhs.bitIs0(bit))  { setBit(bit, 1); }
        else if (lhs.bitIsXZ(bit) && rhs.bitIsXZ(bit)) { setBit(bit,'x'); }
        // else zero
    }
    return *this;
}

V3Number& V3Number::opConcat(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    setZero();
    // See also error in V3Width
    if (!lhs.sized() || !rhs.sized()) {
        v3warn(WIDTHCONCAT, "Unsized numbers/parameters not allowed in concatenations.");
    }
    int obit = 0;
    for (int bit=0; bit<rhs.width(); bit++) {
        setBit(obit, rhs.bitIs(bit));
        obit++;
    }
    for (int bit=0; bit<lhs.width(); bit++) {
        setBit(obit, lhs.bitIs(bit));
        obit++;
    }
    return *this;
}

V3Number& V3Number::opLenN(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_STRING_ARGS1(lhs);
    setQuad(lhs.toString().length());
    return *this;
}

V3Number& V3Number::opRepl(const V3Number& lhs, const V3Number& rhs) {  // rhs is # of times to replicate
    // Hopefully the using routine has a error check to, &rhso.
    // See also error in V3Width
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (!lhs.sized()) {
        v3warn(WIDTHCONCAT, "Unsized numbers/parameters not allowed in replications.");
    }
    return opRepl(lhs, rhs.toUInt());
}

V3Number& V3Number::opRepl(const V3Number& lhs, uint32_t rhsval) {  // rhs is # of times to replicate
    // i op repl, L(i)*value(rhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    if (rhsval > 8192) {
        v3warn(WIDTHCONCAT, "More than a 8k bit replication is probably wrong: "<<rhsval);
    }
    int obit = 0;
    for (unsigned times=0; times<rhsval; times++) {
        for (int bit=0; bit<lhs.width(); bit++) {
            setBit(obit, lhs.bitIs(bit));
            obit++;
        }
    }
    return *this;
}

V3Number& V3Number::opStreamL(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    setZero();
    // See also error in V3Width
    if (!lhs.sized()) {
        v3warn(WIDTHCONCAT, "Unsized numbers/parameters not allowed in streams.");
    }
    // Slice size should never exceed the lhs width
    int ssize = std::min(rhs.toUInt(), static_cast<unsigned>(lhs.width()));
    for (int istart=0; istart<lhs.width(); istart+=ssize) {
        int ostart = std::max(0, lhs.width()-ssize-istart);
        for (int bit=0; bit<ssize && bit<lhs.width()-istart; bit++) {
            setBit(ostart+bit, lhs.bitIs(istart+bit));
        }
    }
    return *this;
}

V3Number& V3Number::opLogAnd(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    char loutc = 0;
    char routc = 0;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs1(bit)) { loutc = 1; break; }
        if (lhs.bitIsXZ(bit) && loutc==0) { loutc = 'x'; }
    }
    for (int bit=0; bit<rhs.width(); bit++) {
        if (rhs.bitIs1(bit)) { routc = 1; break; }
        if (rhs.bitIsXZ(bit) && routc==0) { routc = 'x'; }
    }
    char outc = 'x';
    if (routc==1 && loutc==1) outc=1;
    if (routc==0 || loutc==0) outc=0;
    return setSingleBits(outc);
}

V3Number& V3Number::opLogOr(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    char outc = 0;
    for (int bit=0; bit<lhs.width(); bit++) {
        if (lhs.bitIs1(bit)) { outc = 1; goto last; }
        if (lhs.bitIsXZ(bit) && outc==0) { outc = 'x'; }
    }
    for (int bit=0; bit<rhs.width(); bit++) {
        if (rhs.bitIs1(bit)) { outc = 1; goto last; }
        if (rhs.bitIsXZ(bit) && outc==0) { outc = 'x'; }
    }
last:
    return setSingleBits(outc);
}

V3Number& V3Number::opLogIf(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to
    // X/Z extend. Use definition in IEEE to do this for us.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    V3Number lnot = lhs; lnot.opLogNot(lhs);
    return opLogOr(lnot, rhs);
}

V3Number& V3Number::opLogEq(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to
    // X/Z extend. Use definition in IEEE to do this for us.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    V3Number ifa = lhs; ifa.opLogIf(lhs, rhs);
    V3Number ifb = rhs; ifb.opLogIf(rhs, lhs);
    return opLogAnd(ifa, ifb);
}

V3Number& V3Number::opAtoN(const V3Number& lhs, int base) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_STRING_ARGS1(lhs);
    UASSERT(base == AstAtoN::ATOREAL || base == 2 || base == 8 || base == 10 || base == 16,
            "base must be one of AstAtoN::ATOREAL, 2, 8, 10, or 16.");

    std::string str = lhs.toString();  // new instance to edit later
    if (base == AstAtoN::ATOREAL) return setDouble(std::atof(str.c_str()));

    // IEEE 1800-2017 6.16.9 says '_' may exist.
    str.erase(std::remove(str.begin(), str.end(), '_'), str.end());

    errno = 0;
    long v = std::strtol(str.c_str(), NULL, base);
    if (errno != 0) v = 0;
    return setLongS(static_cast<vlsint32_t>(v));
}

V3Number& V3Number::opPutcN(const V3Number& lhs, const V3Number& rhs, const V3Number& ths) {
    NUM_ASSERT_OP_ARGS3(lhs, rhs, ths);
    NUM_ASSERT_STRING_ARGS1(lhs);
    string lstring = lhs.toString();
    const vlsint32_t i = rhs.toSInt();
    const vlsint32_t c = ths.toSInt() & 0xFF;
    // 6.16.2:str.putc(i, c) does not change the value when i < 0 || i >= str.len() || c == 0
    // when evaluating the second condition, i must be positive.
    if (0 <= i && static_cast<uint32_t>(i) < lstring.length() && c != 0) lstring[i] = c;
    return setString(lstring);
}

V3Number& V3Number::opGetcN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS1(lhs);
    const string lstring = lhs.toString();
    const vlsint32_t i = rhs.toSInt();
    vlsint32_t v = 0;
    // 6.16.3:str.getc(i) returns 0 if i < 0 || i >= str.len()
    // when evaluating the second condition, i must be positive.
    if (0 <= i && static_cast<uint32_t>(i) < lstring.length()) v = lstring[i];
    return setLong(v);
}

V3Number& V3Number::opSubstrN(const V3Number& lhs, const V3Number& rhs, const V3Number& ths) {
    NUM_ASSERT_OP_ARGS3(lhs, rhs, ths);
    NUM_ASSERT_STRING_ARGS1(lhs);
    const string lstring = lhs.toString();
    const vlsint32_t i = rhs.toSInt();
    const vlsint32_t j = ths.toSInt();
    // 6.16.8:str.substr(i, j) returns an empty string when i < 0 || j < i || j >= str.len()
    // when evaluating the third condition, j must be positive because 0 <= i <= j is guaranteed by
    // the former two conditions.
    if (i < 0 || j < i || static_cast<uint32_t>(j) >= lstring.length()) return setString("");
    // The second parameter of std::string::substr(i, n) is length, not position as SystemVerilog.
    return setString(lstring.substr(i, j - i + 1));
}

V3Number& V3Number::opCompareNN(const V3Number& lhs, const V3Number& rhs, bool ignoreCase) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    // SystemVerilog Language Standard does not allow a string variable to contain '\0'.
    // So C functions such as strcmp() can correctly compare strings.
    int result;
    string lstring = lhs.toString();
    string rstring = rhs.toString();
    if (ignoreCase) {
        result = VL_STRCASECMP(lstring.c_str(), rstring.c_str());
    } else {
        result = std::strcmp(lstring.c_str(), rstring.c_str());
    }
    return setLongS(result);
}

V3Number& V3Number::opEq(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    if (lhs.isString()) return opEqN(lhs, rhs);
    if (lhs.isDouble()) return opEqD(lhs, rhs);
    char outc = 1;
    for (int bit=0; bit < std::max(lhs.width(), rhs.width()); bit++) {
        if (lhs.bitIs1(bit) && rhs.bitIs0(bit)) { outc = 0; goto last; }
        if (lhs.bitIs0(bit) && rhs.bitIs1(bit)) { outc = 0; goto last; }
        if (lhs.bitIsXZ(bit)) { outc='x'; }
        if (rhs.bitIsXZ(bit)) { outc='x'; }
    }
last:
    return setSingleBits(outc);
}

V3Number& V3Number::opNeq(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    if (lhs.isString()) return opNeqN(lhs, rhs);
    if (lhs.isDouble()) return opNeqD(lhs, rhs);
    char outc = 0;
    for (int bit=0; bit < std::max(lhs.width(), rhs.width()); bit++) {
        if (lhs.bitIs1(bit) && rhs.bitIs0(bit)) { outc = 1; goto last; }
        if (lhs.bitIs0(bit) && rhs.bitIs1(bit)) { outc = 1; goto last; }
        if (lhs.bitIsXZ(bit)) { outc='x'; }
        if (rhs.bitIsXZ(bit)) { outc='x'; }
    }
last:
    return setSingleBits(outc);
}

bool V3Number::isCaseEq(const V3Number& rhs) const {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    if (isString()) return toString() == rhs.toString();
    if (isDouble()) return toDouble() == rhs.toDouble();
    if (this->width() != rhs.width()) return false;

    for (int bit=0; bit < std::max(this->width(), rhs.width()); bit++) {
        if (this->bitIs(bit) != rhs.bitIs(bit)) { return false; }
    }
    return true;
}

V3Number& V3Number::opCaseEq(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    return setSingleBits(lhs.isCaseEq(rhs) ? 1:0);
}

V3Number& V3Number::opCaseNeq(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    char outc = 0;
    if (lhs.isString()) return opNeqN(lhs, rhs);
    else if (lhs.isDouble()) return opNeqD(lhs, rhs);
    for (int bit=0; bit < std::max(lhs.width(), rhs.width()); bit++) {
        if (lhs.bitIs(bit) != rhs.bitIs(bit)) { outc=1; goto last; }
    }
last:
    return setSingleBits(outc);
}

V3Number& V3Number::opWildEq(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    char outc = 1;
    for (int bit=0; bit < std::max(lhs.width(), rhs.width()); bit++) {
        if (!rhs.bitIsXZ(bit)
            && lhs.bitIs(bit) != rhs.bitIs(bit)) { outc = 0; goto last; }
        if (lhs.bitIsXZ(bit)) outc='x';
    }
last:
    return setSingleBits(outc);
}

V3Number& V3Number::opWildNeq(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    char outc = 0;
    for (int bit=0; bit < std::max(lhs.width(), rhs.width()); bit++) {
        if (!rhs.bitIsXZ(bit)
            && lhs.bitIs(bit) != rhs.bitIs(bit)) { outc=1; goto last; }
        if (lhs.bitIsXZ(bit)) outc='x';
    }
last:
    return setSingleBits(outc);
}

V3Number& V3Number::opGt(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    char outc = 0;
    for (int bit=0; bit < std::max(lhs.width(), rhs.width()); bit++) {
        if (lhs.bitIs1(bit) && rhs.bitIs0(bit)) { outc=1; }
        if (rhs.bitIs1(bit) && lhs.bitIs0(bit)) { outc = 0; }
        if (lhs.bitIsXZ(bit)) { outc='x'; }
        if (rhs.bitIsXZ(bit)) { outc='x'; }
    }
    return setSingleBits(outc);
}

V3Number& V3Number::opGtS(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    char outc = 0;
    {
        int mbit = std::max(lhs.width()-1, rhs.width()-1);
        if (lhs.bitIsXZ(mbit)) { outc='x'; }
        else if (rhs.bitIsXZ(mbit)) { outc='x'; }
        else if (lhs.bitIs0(mbit)       && rhs.bitIs1Extend(mbit)) { outc = 1; }  // + > -
        else if (lhs.bitIs1Extend(mbit) && rhs.bitIs0(mbit))       { outc = 0; }  // - !> +
        else {
            // both positive or negative, normal >
            for (int bit=0; bit < std::max(lhs.width()-1, rhs.width()-1); bit++) {
                if (lhs.bitIs1Extend(bit) && rhs.bitIs0(bit)) { outc = 1; }
                if (rhs.bitIs1Extend(bit) && lhs.bitIs0(bit)) { outc = 0; }
                if (lhs.bitIsXZ(bit)) { outc = 'x'; }
                if (rhs.bitIsXZ(bit)) { outc = 'x'; }
            }
        }
    }
    return setSingleBits(outc);
}

V3Number& V3Number::opGte(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    V3Number& eq = opEq(lhs, rhs);
    if (eq.isNeqZero()) return eq;  // Return true
    return opGt(lhs, rhs);
}

V3Number& V3Number::opGteS(const V3Number& lhs, const V3Number& rhs) {
    // i op j, 1 bit return, max(L(lhs),L(rhs)) calculation, careful need to X/Z extend.
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    V3Number& eq = opEq(lhs, rhs);
    if (eq.isNeqZero()) return eq;  // Return true
    return opGtS(lhs, rhs);
}

V3Number& V3Number::opLt(const V3Number& lhs, const V3Number& rhs) {
    return opGt(rhs, lhs);
}
V3Number& V3Number::opLte(const V3Number& lhs, const V3Number& rhs) {
    return opGte(rhs, lhs);
}
V3Number& V3Number::opLtS(const V3Number& lhs, const V3Number& rhs) {
    return opGtS(rhs, lhs);
}
V3Number& V3Number::opLteS(const V3Number& lhs, const V3Number& rhs) {
    return opGteS(rhs, lhs);
}

V3Number& V3Number::opRotR(const V3Number& lhs, const V3Number& rhs) {
    // L(lhs) bit return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (rhs.isFourState()) return setAllBitsX();
    setZero();
    uint32_t rhsval = rhs.toUInt();
    for (int bit=0; bit<this->width(); bit++) {
        setBit(bit, lhs.bitIs((bit + rhsval) % this->width()));
    }
    return *this;
}

V3Number& V3Number::opRotL(const V3Number& lhs, const V3Number& rhs) {
    // L(lhs) bit return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (rhs.isFourState()) return setAllBitsX();
    setZero();
    uint32_t rhsval = rhs.toUInt();
    for (int bit=0; bit<this->width(); bit++) {
        if (bit >= static_cast<int>(rhsval)) {
            setBit(bit, lhs.bitIs((bit - rhsval) % this->width()));
        }
    }
    return *this;
}

V3Number& V3Number::opShiftR(const V3Number& lhs, const V3Number& rhs) {
    // L(lhs) bit return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (rhs.isFourState()) return setAllBitsX();
    setZero();
    for (int bit=32; bit<rhs.width(); bit++) {
        if (rhs.bitIs1(bit)) return *this;  // shift of over 2^32 must be zero
    }
    uint32_t rhsval = rhs.toUInt();
    if (rhsval < static_cast<uint32_t>(lhs.width())) {
        for (int bit=0; bit<this->width(); bit++) {
            setBit(bit, lhs.bitIs(bit + rhsval));
        }
    }
    return *this;
}

V3Number& V3Number::opShiftRS(const V3Number& lhs, const V3Number& rhs, uint32_t lbits) {
    // L(lhs) bit return
    // The spec says a unsigned >>> still acts as a normal >>.
    // We presume it is signed; as that's V3Width's job to convert to opShiftR
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (rhs.isFourState()) return setAllBitsX();
    setZero();
    for (int bit=32; bit<rhs.width(); bit++) {
        for (int sbit = 0; sbit < this->width(); sbit++) {
            setBit(sbit, lhs.bitIs(lbits - 1));  // 0/1/X/Z
        }
        if (rhs.bitIs1(lbits-1)) setAllBits1();  // -1 else 0
        return *this;  // shift of over 2^32 must be -1/0
    }
    uint32_t rhsval = rhs.toUInt();
    if (rhsval < static_cast<uint32_t>(lhs.width())) {
        for (int bit=0; bit<this->width(); bit++) {
            setBit(bit, lhs.bitIsExtend(bit + rhsval, lbits));
        }
    } else {
        for (int bit=0; bit<this->width(); bit++) {
            setBit(bit, lhs.bitIs(lbits-1));  // 0/1/X/Z
        }
    }
    return *this;
}

V3Number& V3Number::opShiftL(const V3Number& lhs, const V3Number& rhs) {
    // L(lhs) bit return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (rhs.isFourState()) return setAllBitsX();
    setZero();
    for (int bit=32; bit<rhs.width(); bit++) {
        if (rhs.bitIs1(bit)) return *this;  // shift of over 2^32 must be zero
    }
    uint32_t rhsval = rhs.toUInt();
    for (int bit=0; bit<this->width(); bit++) {
        if (bit >= static_cast<int>(rhsval)) {
            setBit(bit, lhs.bitIs(bit - rhsval));
        }
    }
    return *this;
}

//======================================================================
// Ops - Arithmetic

V3Number& V3Number::opAbsS(const V3Number& lhs) {
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    if (lhs.isFourState()) return setAllBitsX();
    if (lhs.isNegative()) {
        return opNegate(lhs);
    } else {
        return opAssign(lhs);
    }
}
V3Number& V3Number::opNegate(const V3Number& lhs) {
    // op i, L(lhs) bit return
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    if (lhs.isFourState()) return setAllBitsX();
    V3Number notlhs (&lhs, width());
    notlhs.opNot(lhs);
    V3Number one (&lhs, width(), 1);
    opAdd(notlhs, one);
    return *this;
}
V3Number& V3Number::opAdd(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, if any 4-state, 4-state return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    setZero();
    // Addem
    int carry=0;
    for (int bit=0; bit<this->width(); bit++) {
        int sum = ((lhs.bitIs1(bit)?1:0) + (rhs.bitIs1(bit)?1:0) + carry);
        if (sum & 1) {
            setBit(bit, 1);
        }
        carry = (sum >= 2);
    }
    return *this;
}
V3Number& V3Number::opSub(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, if any 4-state, 4-state return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    V3Number negrhs (&rhs, rhs.width());
    negrhs.opNegate(rhs);
    return opAdd(lhs, negrhs);
}
V3Number& V3Number::opMul(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, if any 4-state, 4-state return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    setZero();
    if (width() <= 64) {
        setQuad(lhs.toUQuad() * rhs.toUQuad());
        opCleanThis();  // Mult produces extra bits in result
    } else {
        for (int lword=0; lword<lhs.words(); lword++) {
            for (int rword=0; rword<rhs.words(); rword++) {
                vluint64_t mul = static_cast<vluint64_t>(lhs.m_value[lword])
                    * static_cast<vluint64_t>(rhs.m_value[rword]);
                for (int qword=lword+rword; qword<this->words(); qword++) {
                    mul += static_cast<vluint64_t>(m_value[qword]);
                    m_value[qword] = (mul & VL_ULL(0xffffffff));
                    mul = (mul >> VL_ULL(32)) & VL_ULL(0xffffffff);
                }
            }
        }
        opCleanThis();  // Mult produces extra bits in result
    }
    return *this;
}
V3Number& V3Number::opMulS(const V3Number& lhs, const V3Number& rhs) {
    // Signed multiply
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    V3Number lhsNoSign = lhs;  if (lhs.isNegative()) lhsNoSign.opNegate(lhs);
    V3Number rhsNoSign = rhs;  if (rhs.isNegative()) rhsNoSign.opNegate(rhs);
    V3Number qNoSign = opMul(lhsNoSign, rhsNoSign);
    if ((lhs.isNegative() && !rhs.isNegative())
        || (!lhs.isNegative() && rhs.isNegative())) {
        opNegate(qNoSign);
    } else {
        opAssign(qNoSign);
    }
    return *this;
}
V3Number& V3Number::opDiv(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, if any 4-state, 4-state return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    //UINFO(9, "opdiv "<<lhs<<" "<<rhs<<endl);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    if (rhs.isEqZero()) return setAllBitsXRemoved();
    if (lhs.width()<=64) {
        setQuad(lhs.toUQuad() / rhs.toUQuad());
        return *this;
    } else {
        // Wide division
        return opModDivGuts(lhs, rhs, false);
    }
}
V3Number& V3Number::opDivS(const V3Number& lhs, const V3Number& rhs) {
    // Signed divide
    //UINFO(9, ">>divs-start "<<lhs<<" "<<rhs<<endl);
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    if (rhs.isEqZero()) return setAllBitsXRemoved();
    V3Number lhsNoSign = lhs;  if (lhs.isNegative()) lhsNoSign.opNegate(lhs);
    V3Number rhsNoSign = rhs;  if (rhs.isNegative()) rhsNoSign.opNegate(rhs);
    V3Number qNoSign = opDiv(lhsNoSign, rhsNoSign);
    //UINFO(9, " >divs-mid "<<lhs<<" "<<rhs<<" "<<qNoSign<<endl);
    if ((lhs.isNegative() && !rhs.isNegative())
        || (!lhs.isNegative() && rhs.isNegative())) {
        opNegate(qNoSign);
    } else {
        opAssign(qNoSign);
    }
    UINFO(9, " <divs-out "<<lhs<<" "<<rhs<<" ="<<*this<<endl);
    return *this;
}
V3Number& V3Number::opModDiv(const V3Number& lhs, const V3Number& rhs) {
    // i op j, max(L(lhs),L(rhs)) bit return, if any 4-state, 4-state return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    if (rhs.isEqZero()) return setAllBitsXRemoved();
    if (lhs.width()<=64) {
        setQuad(lhs.toUQuad() % rhs.toUQuad());
        return *this;
    } else {
        // Wide modulus
        return opModDivGuts(lhs, rhs, true);
    }
}
V3Number& V3Number::opModDivS(const V3Number& lhs, const V3Number& rhs) {
    // Signed moddiv
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    if (rhs.isEqZero()) return setAllBitsXRemoved();
    V3Number lhsNoSign = lhs;  if (lhs.isNegative()) lhsNoSign.opNegate(lhs);
    V3Number rhsNoSign = rhs;  if (rhs.isNegative()) rhsNoSign.opNegate(rhs);
    V3Number qNoSign = opModDiv(lhsNoSign, rhsNoSign);
    if (lhs.isNegative()) {  // Just lhs' sign  (*DIFFERENT FROM PERL, which uses rhs sign*)
        opNegate(qNoSign);
    } else {
        opAssign(qNoSign);
    }
    return *this;
}
V3Number& V3Number::opModDivGuts(const V3Number& lhs, const V3Number& rhs, bool is_modulus) {
    // See Knuth Algorithm D.  Computes u/v = q.r
    // This isn't massively tuned, as wide division is rare
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    setZero();
    // Find MSB and check for zero.
    int words = lhs.words();
    int umsbp1 = lhs.mostSetBitP1();  // dividend
    int vmsbp1 = rhs.mostSetBitP1();  // divisor
    if (VL_UNLIKELY(vmsbp1==0)  // rwp==0 so division by zero.  Return 0.
        || VL_UNLIKELY(umsbp1==0)) {  // 0/x so short circuit and return 0
        UINFO(9, "  opmoddiv-zero "<<lhs<<" "<<rhs<<" now="<<*this<<endl);
        return *this;
    }

    int uw = (umsbp1 + 31) / 32;  // aka "m" in the algorithm
    int vw = (vmsbp1 + 31) / 32;  // aka "n" in the algorithm

    if (vw == 1) {  // Single divisor word breaks rest of algorithm
        vluint64_t k = 0;
        for (int j = uw-1; j >= 0; j--) {
            vluint64_t unw64 = ((k<<VL_ULL(32)) + static_cast<vluint64_t>(lhs.m_value[j]));
            m_value[j] = unw64 / static_cast<vluint64_t>(rhs.m_value[0]);
            k          = unw64 - (static_cast<vluint64_t>(m_value[j])
                                  * static_cast<vluint64_t>(rhs.m_value[0]));
        }
        UINFO(9, "  opmoddiv-1w  "<<lhs<<" "<<rhs<<" q="<<*this
              <<" rem=0x"<<std::hex<<k<<std::dec<<endl);
        if (is_modulus) { setZero(); m_value[0] = k; }
        opCleanThis();
        return *this;
    }

    // +1 word as we may shift during normalization
    uint32_t un[VL_MULS_MAX_WORDS+1];  // Fixed size, as MSVC++ doesn't allow [words] here
    uint32_t vn[VL_MULS_MAX_WORDS+1];  // v normalized

    // Zero for ease of debugging and to save having to zero for shifts
    for (int i=0; i<words; i++) { m_value[i]=0; }
    for (int i=0; i<words+1; i++) { un[i]=vn[i]=0; }  // +1 as vn may get extra word

    // Algorithm requires divisor MSB to be set
    // Copy and shift to normalize divisor so MSB of vn[vw-1] is set
    int s = 31 - ((vmsbp1-1) & 31);  // shift amount (0...31)
    uint32_t shift_mask = s ? 0xffffffff : 0;  // otherwise >> 32 won't mask the value
    for (int i = vw-1; i>0; i--) {
        vn[i] = (rhs.m_value[i] << s) | (shift_mask & (rhs.m_value[i-1] >> (32-s)));
    }
    vn[0] = rhs.m_value[0] << s;

    // Copy and shift dividend by same amount; may set new upper word
    if (s) un[uw] = lhs.m_value[uw-1] >> (32-s);
    else   un[uw] = 0;
    for (int i=uw-1; i>0; i--) {
        un[i] = (lhs.m_value[i] << s) | (shift_mask & (lhs.m_value[i-1] >> (32-s)));
    }
    un[0] = lhs.m_value[0] << s;

    //printf("  un="); for (int i=5; i>=0; i--) printf(" %08x",un[i]); printf("\n");
    //printf("  vn="); for (int i=5; i>=0; i--) printf(" %08x",vn[i]); printf("\n");
    //printf("  mv="); for (int i=5; i>=0; i--) printf(" %08x",m_value[i]); printf("\n");

    // Main loop
    for (int j = uw - vw; j >= 0; j--) {
        // Estimate
        vluint64_t unw64 = (static_cast<vluint64_t>(un[j+vw])<<VL_ULL(32)
                            | static_cast<vluint64_t>(un[j+vw-1]));
        vluint64_t qhat = unw64 / static_cast<vluint64_t>(vn[vw-1]);
        vluint64_t rhat = unw64 - qhat*static_cast<vluint64_t>(vn[vw-1]);

      again:
        if (qhat >= VL_ULL(0x100000000)
            || ((qhat*vn[vw-2]) > ((rhat<<VL_ULL(32)) + un[j+vw-2]))) {
            qhat = qhat - 1;
            rhat = rhat + vn[vw-1];
            if (rhat < VL_ULL(0x100000000)) goto again;
        }

        vlsint64_t t = 0;  // Must be signed
        vluint64_t k = 0;
        for (int i=0; i<vw; i++) {
            vluint64_t p = qhat*vn[i];  // Multiply by estimate
            t = un[i+j] - k - (p & VL_ULL(0xFFFFFFFF));  // Subtract
            un[i+j] = t;
            k = (p >> VL_ULL(32)) - (t >> VL_ULL(32));
        }
        t = un[j+vw] - k;
        un[j+vw] = t;
        this->m_value[j] = qhat;  // Save quotient digit

        if (t < 0) {
            // Over subtracted; correct by adding back
            this->m_value[j]--;
            k = 0;
            for (int i=0; i<vw; i++) {
                t = static_cast<vluint64_t>(un[i+j]) + static_cast<vluint64_t>(vn[i]) + k;
                un[i+j] = t;
                k = t >> VL_ULL(32);
            }
            un[j+vw] = un[j+vw] + k;
        }
    }

    //printf("  un="); for (int i=5; i>=0; i--) printf(" %08x",un[i]); printf("\n");
    //printf("  vn="); for (int i=5; i>=0; i--) printf(" %08x",vn[i]); printf("\n");
    //printf("  mv="); for (int i=5; i>=0; i--) printf(" %08x",m_value[i]); printf("\n");

    if (is_modulus) {  // modulus
        // Need to reverse normalization on copy to output
        for (int i=0; i<vw; i++) {
            m_value[i] = (un[i] >> s) | (shift_mask & (un[i+1] << (32-s)));
        }
        for (int i=vw; i<words; i++) m_value[i] = 0;
        opCleanThis();
        UINFO(9, "  opmoddiv-mod "<<lhs<<" "<<rhs<<" now="<<*this<<endl);
        return *this;
    } else {  // division
        opCleanThis();
        UINFO(9, "  opmoddiv-div "<<lhs<<" "<<rhs<<" now="<<*this<<endl);
        return *this;
    }
}

V3Number& V3Number::opPow(const V3Number& lhs, const V3Number& rhs, bool lsign, bool rsign) {
    // L(i) bit return, if any 4-state, 4-state return
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_LOGIC_ARGS2(lhs, rhs);
    if (lhs.isFourState() || rhs.isFourState()) return setAllBitsX();
    if (rhs.isEqZero()) return setQuad(1);  // Overrides lhs 0 -> return 0
    // We may want to special case when the lhs is 2, so we can get larger outputs
    if (rsign && rhs.isNegative()) {
        if (lhs.isEqZero()) return setAllBitsXRemoved();
        else if (lhs.isEqOne()) return setQuad(1);
        else if (lsign && lhs.isEqAllOnes()) {
            if (rhs.bitIs1(0)) return setAllBits1();  // -1^odd=-1
            else return setQuad(1);  // -1^even=1
        }
        return setZero();
    }
    if (lhs.isEqZero()) return setZero();
    setZero();
    m_value[0] = 1;
    V3Number power (&lhs, width());  power.opAssign(lhs);
    for (int bit=0; bit<rhs.width(); bit++) {
        if (bit>0) {  // power = power*power
            V3Number lastPower (&lhs, width());  lastPower.opAssign(power);
            power.opMul(lastPower, lastPower);
        }
        if (rhs.bitIs1(bit)) {  // out *= power
            V3Number lastOut (&lhs, width()); lastOut.opAssign(*this);
            this->opMul(lastOut, power);
            //UINFO(0, "pow "<<lhs<<" "<<rhs<<" b"<<bit<<" pow="<<power<<" now="<<*this<<endl);
        }
    }
    return *this;
}
V3Number& V3Number::opPowSU(const V3Number& lhs, const V3Number& rhs) {
    return opPow(lhs, rhs, true, false);
}
V3Number& V3Number::opPowSS(const V3Number& lhs, const V3Number& rhs) {
    return opPow(lhs, rhs, true, true);
}
V3Number& V3Number::opPowUS(const V3Number& lhs, const V3Number& rhs) {
    return opPow(lhs, rhs, false, true);
}

V3Number& V3Number::opBufIf1(const V3Number& ens, const V3Number& if1s) {
    NUM_ASSERT_OP_ARGS2(ens, if1s);
    NUM_ASSERT_LOGIC_ARGS2(ens, if1s);
    setZero();
    for (int bit=0; bit<this->width(); bit++) {
        if (ens.bitIs1(bit))  { setBit(bit, if1s.bitIs(bit)); }
        else setBit(bit,'z');
    }
    return *this;
}

V3Number& V3Number::opAssign(const V3Number& lhs) { return opAssignNonXZ(lhs, false); }
V3Number& V3Number::opAssignNonXZ(const V3Number& lhs, bool ignoreXZ) {
    // Note may be a width change during the assign.
    // Special case: opAssign unlike other ops, allows this an assignment
    // to itself; V3Simulate does this when hits "foo=foo;"
    // So no: NUM_ASSERT_OP_ARGS1(lhs);
    if (this != &lhs) {
        setZero();
        if (isString()) {
            m_stringVal = lhs.m_stringVal;
        } else {
            // Also handles double as is just bits
            for (int bit = 0; bit < this->width(); bit++) {
                setBit(bit, ignoreXZ ? lhs.bitIs1(bit) : lhs.bitIs(bit));
            }
        }
    }
    return *this;
}

V3Number& V3Number::opExtendS(const V3Number& lhs, uint32_t lbits) {
    // Note may be a width change during the sign extension
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit < width(); bit++) {
        char extendWith = lhs.bitIsExtend(bit, lbits);
        setBit(bit, extendWith);
    }
    return *this;
}

V3Number& V3Number::opExtendXZ(const V3Number& lhs, uint32_t lbits) {
    // Note may be a width change during the X/Z extension
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    for (int bit=0; bit < width(); bit++) {
        char extendWith = lhs.bitIsExtend(bit, lbits);
        if (extendWith == '1' || extendWith == 1) extendWith = 0;
        setBit(bit, lhs.bitIsExtend(bit, lbits));
    }
    return *this;
}

V3Number& V3Number::opClean(const V3Number& lhs, uint32_t bits) {
    return opSel(lhs, bits-1, 0);
}

void V3Number::opCleanThis(bool warnOnTruncation) {
    // Clean MSB of number
    NUM_ASSERT_LOGIC_ARGS1(*this);
    uint32_t newValueMsb = m_value[words()-1]  & hiWordMask();
    uint32_t newValueXMsb = m_valueX[words()-1] & hiWordMask();
    if (warnOnTruncation && (newValueMsb != m_value[words()-1]
                             || newValueXMsb != m_valueX[words()-1])) {
        // Displaying in decimal avoids hiWordMask truncation
        v3warn(WIDTH, "Value too large for "<<width()<<" bit number: "<<displayed("%d"));
    }
    m_value[words()-1]  = newValueMsb;
    m_valueX[words()-1] = newValueXMsb;
}

V3Number& V3Number::opSel(const V3Number& lhs, const V3Number& msb, const V3Number& lsb) {
    NUM_ASSERT_OP_ARGS3(lhs, msb, lsb);
    NUM_ASSERT_LOGIC_ARGS1(lhs); NUM_ASSERT_LOGIC_ARGS2(msb, lsb);
    if (lsb.isFourState() || msb.isFourState()) return setAllBitsX();
    return opSel(lhs, msb.toUInt(), lsb.toUInt());
}

V3Number& V3Number::opSel(const V3Number& lhs, uint32_t msbval, uint32_t lsbval) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    setZero();
    int ibit = lsbval;
    for (int bit=0; bit<this->width(); bit++) {
        if (ibit>=0 && ibit<lhs.width()
            && ibit <= static_cast<int>(msbval)) {
            setBit(bit, lhs.bitIs(ibit));
        } else {
            setBit(bit, 'x');
        }
        ++ibit;
    }
    //UINFO(0,"RANGE "<<lhs<<" "<<msb<<" "<<lsb<<" = "<<*this<<endl);
    return *this;
}

V3Number& V3Number::opSelInto(const V3Number& lhs, const V3Number& lsb, int width) {
    return opSelInto(lhs, lsb.toSInt(), width);
}

V3Number& V3Number::opSelInto(const V3Number& lhs, int lsbval, int width) {
    // this[lsbval+width-1 : lsbval] = lhs;  Other bits of this are not affected
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    int ibit = 0;
    for (int bit=lsbval; bit<lsbval+width; bit++) {
        if (ibit>=0 && ibit<lhs.width()) {
            setBit(bit, lhs.bitIs(ibit));
        } else {
            setBit(bit, 'x');
        }
        ibit++;
    }
    return *this;
}

V3Number& V3Number::opCond(const V3Number& lhs, const V3Number& if1s, const V3Number& if0s) {
    NUM_ASSERT_OP_ARGS3(lhs, if1s, if0s);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    V3Number lhstrue (&lhs);  lhstrue.opRedOr(lhs);
    if (lhstrue.bitIs0(0)) {
        this->opAssign(if0s);
    }
    else if (lhstrue.bitIs1(0)) {
        this->opAssign(if1s);
    }
    else {  // select is "X/Z"
        setZero();
        NUM_ASSERT_LOGIC_ARGS2(if1s, if0s);
        for (int bit=0; bit<this->width(); bit++) {
            if (if0s.bitIs1(bit) && if1s.bitIs1(bit))  { setBit(bit, 1); }
            else if (if0s.bitIs0(bit) && if1s.bitIs0(bit))  { setBit(bit, 0); }
            else setBit(bit,'x');
        }
    }
    return *this;
}

//======================================================================
// Ops - Floating point

V3Number& V3Number::opIToRD(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_LOGIC_ARGS1(lhs);
    // IEEE says we ignore x/z in real conversions
    V3Number noxz(lhs);
    noxz.opAssignNonXZ(lhs);
    return setDouble(noxz.toSInt());
}
V3Number& V3Number::opRToIS(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_DOUBLE_ARGS1(lhs);
    double v = VL_TRUNC(lhs.toDouble());
    vlsint32_t i = static_cast<vlsint32_t>(v);  // C converts from double to vlsint32
    return setLongS(i);
}
V3Number& V3Number::opRToIRoundS(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_DOUBLE_ARGS1(lhs);
    double v = VL_ROUND(lhs.toDouble());
    setZero();
    union { double d; vluint64_t q; } u;
    u.d = v; if (u.d == 0.0) {}

    int exp = static_cast<int>((u.q >> VL_ULL(52)) & VL_MASK_Q(11)) - 1023;
    int lsb = exp - 52;
    vluint64_t mantissa = (u.q & VL_MASK_Q(52)) | (VL_ULL(1) << 52);
    if (v != 0) {
        // IEEE format: [63]=sign [62:52]=exp+1023 [51:0]=mantissa
        // This does not need to support subnormals as they are sub-integral
        for (int bit = 0; bit <= 52; ++bit) {
            if (mantissa & (VL_ULL(1) << bit)) {
                int outbit = bit + lsb;
                if (outbit >= 0) setBit(outbit, 1);
            }
        }
        if (v < 0) {
            V3Number noSign = *this;
            opNegate(noSign);
        }
    }
    return *this;
}
V3Number& V3Number::opRealToBits(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_DOUBLE_ARGS1(lhs);
    // Conveniently our internal format is identical so we can copy bits...
    if (lhs.width()!=64 || this->width()!=64) {
        v3fatalSrc("Real operation on wrong sized number");
    }
    opAssign(lhs);
    m_double = false;
    return *this;
}
V3Number& V3Number::opBitsToRealD(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    // Conveniently our internal format is identical so we can copy bits...
    if (lhs.width()!=64 || this->width()!=64) {
        v3fatalSrc("Real operation on wrong sized number");
    }
    opAssign(lhs);
    m_double = true;
    return *this;
}
V3Number& V3Number::opNegateD(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_DOUBLE_ARGS1(lhs);
    return setDouble(- lhs.toDouble());
}
V3Number& V3Number::opAddD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setDouble(lhs.toDouble() + rhs.toDouble());
}
V3Number& V3Number::opSubD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setDouble(lhs.toDouble() - rhs.toDouble());
}
V3Number& V3Number::opMulD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setDouble(lhs.toDouble() * rhs.toDouble());
}
V3Number& V3Number::opDivD(const V3Number& lhs, const V3Number& rhs) {
    // On exceptions, we just generate 'inf' through floating point
    // IEEE says it's implementation defined what happens
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setDouble(lhs.toDouble() / rhs.toDouble());
}
V3Number& V3Number::opPowD(const V3Number& lhs, const V3Number& rhs) {
    // On exceptions, we just generate 'inf' through floating point
    // IEEE says it's implementation defined what happens
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setDouble(pow(lhs.toDouble(), rhs.toDouble()));
}
V3Number& V3Number::opEqD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toDouble() == rhs.toDouble());
}
V3Number& V3Number::opNeqD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toDouble() != rhs.toDouble());
}
V3Number& V3Number::opGtD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toDouble() > rhs.toDouble());
}
V3Number& V3Number::opGteD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toDouble() >= rhs.toDouble());
}
V3Number& V3Number::opLtD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toDouble() < rhs.toDouble());
}
V3Number& V3Number::opLteD(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_DOUBLE_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toDouble() <= rhs.toDouble());
}

//======================================================================
// Ops - String

V3Number& V3Number::opConcatN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setString(lhs.toString() + rhs.toString());
}
V3Number& V3Number::opReplN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_STRING_ARGS1(lhs); NUM_ASSERT_LOGIC_ARGS1(rhs);
    return opReplN(lhs, rhs.toUInt());
}
V3Number& V3Number::opReplN(const V3Number& lhs, uint32_t rhsval) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_STRING_ARGS1(lhs);
    string out; out.reserve(lhs.toString().length() * rhsval);
    for (unsigned times=0; times<rhsval; times++) {
        out += lhs.toString();
    }
    return setString(out);
}
V3Number& V3Number::opToLowerN(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_STRING_ARGS1(lhs);
    std::string out = lhs.toString();
    for (std::string::iterator it = out.begin(); it != out.end(); ++it) {
        *it = tolower(*it);
    }
    return setString(out);
}
V3Number& V3Number::opToUpperN(const V3Number& lhs) {
    NUM_ASSERT_OP_ARGS1(lhs);
    NUM_ASSERT_STRING_ARGS1(lhs);
    std::string out = lhs.toString();
    for (std::string::iterator it = out.begin(); it != out.end(); ++it) {
        *it = toupper(*it);
    }
    return setString(out);
}

V3Number& V3Number::opEqN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toString() == rhs.toString());
}
V3Number& V3Number::opNeqN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toString() != rhs.toString());
}
V3Number& V3Number::opGtN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toString() > rhs.toString());
}
V3Number& V3Number::opGteN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toString() >= rhs.toString());
}
V3Number& V3Number::opLtN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toString() < rhs.toString());
}
V3Number& V3Number::opLteN(const V3Number& lhs, const V3Number& rhs) {
    NUM_ASSERT_OP_ARGS2(lhs, rhs);
    NUM_ASSERT_STRING_ARGS2(lhs, rhs);
    return setSingleBits(lhs.toString() <= rhs.toString());
}