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Support > 64 bit decimal $display.

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This commit is contained in:
Wilson Snyder
2017-12-02 22:10:58 -05:00
parent 754527edfd
commit 895fc0911a
9 changed files with 226 additions and 38 deletions
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src/V3Number.cpp
+64 -9
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@@ -539,15 +539,19 @@ string V3Number::displayed(FileLine*fl, const string& vformat) const {
if (issigned) dchars++; // space for sign
fmtsize = cvtToStr(int(dchars));
}
if (width() > 64) {
fl->v3error("Unsupported: $display-like format of decimal of > 64 bit results (use hex format instead)");
return "ERR";
}
if (issigned) {
str = cvtToStr(toSQuad());
} else {
str = cvtToStr(toUQuad());
}
if (issigned) {
if (width() > 64) {
str = toDecimalS();
} else {
str = cvtToStr(toSQuad());
}
} else {
if (width() > 64) {
str = toDecimalU();
} else {
str = cvtToStr(toUQuad());
}
}
int intfmtsize = atoi(fmtsize.c_str());
bool zeropad = fmtsize.length()>0 && fmtsize[0]=='0';
while ((int)(str.length()) < intfmtsize) {
@@ -606,6 +610,57 @@ string V3Number::displayed(FileLine*fl, const string& vformat) const {
}
}
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 (fileline(), maxdecwidth+4);
V3Number tmp (fileline(), maxdecwidth+4);
V3Number tmp2 (fileline(), 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, decompsed 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(fileline(), 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