else if (digitValue < 8 && digitValue > 0)
return lfLessThanHalf;
- /* Otherwise we need to find the first non-zero digit. */
- while (*p == '0')
+ // Otherwise we need to find the first non-zero digit.
+ while (p != end && (*p == '0' || *p == '.'))
p++;
assert(p != end && "Invalid trailing hexadecimal fraction!");
APFloat::APFloat(const fltSemantics &ourSemantics, integerPart value) {
initialize(&ourSemantics);
sign = 0;
+ category = fcNormal;
zeroSignificand();
exponent = ourSemantics.precision - 1;
significandParts()[0] = value;
void
APFloat::zeroSignificand()
{
- category = fcNormal;
APInt::tcSet(significandParts(), 0, partCount());
}
case PackCategoriesIntoKey(fcZero, fcNaN):
case PackCategoriesIntoKey(fcNormal, fcNaN):
case PackCategoriesIntoKey(fcInfinity, fcNaN):
+ sign = false;
category = fcNaN;
copySignificand(rhs);
return opOK;
case PackCategoriesIntoKey(fcNaN, fcNormal):
case PackCategoriesIntoKey(fcNaN, fcInfinity):
case PackCategoriesIntoKey(fcNaN, fcNaN):
+ sign = false;
return opOK;
case PackCategoriesIntoKey(fcZero, fcNaN):
case PackCategoriesIntoKey(fcNormal, fcNaN):
case PackCategoriesIntoKey(fcInfinity, fcNaN):
+ sign = false;
category = fcNaN;
copySignificand(rhs);
return opOK;
default:
llvm_unreachable(0);
+ case PackCategoriesIntoKey(fcZero, fcNaN):
+ case PackCategoriesIntoKey(fcNormal, fcNaN):
+ case PackCategoriesIntoKey(fcInfinity, fcNaN):
+ category = fcNaN;
+ copySignificand(rhs);
case PackCategoriesIntoKey(fcNaN, fcZero):
case PackCategoriesIntoKey(fcNaN, fcNormal):
case PackCategoriesIntoKey(fcNaN, fcInfinity):
case PackCategoriesIntoKey(fcNaN, fcNaN):
+ sign = false;
case PackCategoriesIntoKey(fcInfinity, fcZero):
case PackCategoriesIntoKey(fcInfinity, fcNormal):
case PackCategoriesIntoKey(fcZero, fcInfinity):
case PackCategoriesIntoKey(fcZero, fcNormal):
return opOK;
- case PackCategoriesIntoKey(fcZero, fcNaN):
- case PackCategoriesIntoKey(fcNormal, fcNaN):
- case PackCategoriesIntoKey(fcInfinity, fcNaN):
- category = fcNaN;
- copySignificand(rhs);
- return opOK;
-
case PackCategoriesIntoKey(fcNormal, fcInfinity):
category = fcZero;
return opOK;
case PackCategoriesIntoKey(fcZero, fcNaN):
case PackCategoriesIntoKey(fcNormal, fcNaN):
case PackCategoriesIntoKey(fcInfinity, fcNaN):
+ sign = false;
category = fcNaN;
copySignificand(rhs);
return opOK;
X86SpecialNan = true;
}
+ // If this is a truncation of a denormal number, and the target semantics
+ // has larger exponent range than the source semantics (this can happen
+ // when truncating from PowerPC double-double to double format), the
+ // right shift could lose result mantissa bits. Adjust exponent instead
+ // of performing excessive shift.
+ if (shift < 0 && isFiniteNonZero()) {
+ int exponentChange = significandMSB() + 1 - fromSemantics.precision;
+ if (exponent + exponentChange < toSemantics.minExponent)
+ exponentChange = toSemantics.minExponent - exponent;
+ if (exponentChange < shift)
+ exponentChange = shift;
+ if (exponentChange < 0) {
+ shift -= exponentChange;
+ exponent += exponentChange;
+ }
+ }
+
// If this is a truncation, perform the shift before we narrow the storage.
if (shift < 0 && (isFiniteNonZero() || category==fcNaN))
lostFraction = shiftRight(significandParts(), oldPartCount, -shift);
APFloat::convertFromHexadecimalString(StringRef s, roundingMode rounding_mode)
{
lostFraction lost_fraction = lfExactlyZero;
- integerPart *significand;
- unsigned int bitPos, partsCount;
- StringRef::iterator dot, firstSignificantDigit;
+ category = fcNormal;
zeroSignificand();
exponent = 0;
- category = fcNormal;
- significand = significandParts();
- partsCount = partCount();
- bitPos = partsCount * integerPartWidth;
+ integerPart *significand = significandParts();
+ unsigned partsCount = partCount();
+ unsigned bitPos = partsCount * integerPartWidth;
+ bool computedTrailingFraction = false;
- /* Skip leading zeroes and any (hexa)decimal point. */
+ // Skip leading zeroes and any (hexa)decimal point.
StringRef::iterator begin = s.begin();
StringRef::iterator end = s.end();
+ StringRef::iterator dot;
StringRef::iterator p = skipLeadingZeroesAndAnyDot(begin, end, &dot);
- firstSignificantDigit = p;
+ StringRef::iterator firstSignificantDigit = p;
- for (; p != end;) {
+ while (p != end) {
integerPart hex_value;
if (*p == '.') {
assert(dot == end && "String contains multiple dots");
dot = p++;
- if (p == end) {
- break;
- }
+ continue;
}
hex_value = hexDigitValue(*p);
- if (hex_value == -1U) {
+ if (hex_value == -1U)
break;
- }
p++;
- if (p == end) {
- break;
- } else {
- /* Store the number whilst 4-bit nibbles remain. */
- if (bitPos) {
- bitPos -= 4;
- hex_value <<= bitPos % integerPartWidth;
- significand[bitPos / integerPartWidth] |= hex_value;
- } else {
- lost_fraction = trailingHexadecimalFraction(p, end, hex_value);
- while (p != end && hexDigitValue(*p) != -1U)
- p++;
- break;
- }
+ // Store the number while we have space.
+ if (bitPos) {
+ bitPos -= 4;
+ hex_value <<= bitPos % integerPartWidth;
+ significand[bitPos / integerPartWidth] |= hex_value;
+ } else if (!computedTrailingFraction) {
+ lost_fraction = trailingHexadecimalFraction(p, end, hex_value);
+ computedTrailingFraction = true;
}
}
42039/12655 < L < 28738/8651 [ numerator <= 65536 ]
*/
- if (decDigitValue(*D.firstSigDigit) >= 10U) {
+ // Test if we have a zero number allowing for strings with no null terminators
+ // and zero decimals with non-zero exponents.
+ //
+ // We computed firstSigDigit by ignoring all zeros and dots. Thus if
+ // D->firstSigDigit equals str.end(), every digit must be a zero and there can
+ // be at most one dot. On the other hand, if we have a zero with a non-zero
+ // exponent, then we know that D.firstSigDigit will be non-numeric.
+ if (D.firstSigDigit == str.end() || decDigitValue(*D.firstSigDigit) >= 10U) {
category = fcZero;
fs = opOK;
(D.normalizedExponent + 1) * 28738 <=
8651 * (semantics->minExponent - (int) semantics->precision)) {
/* Underflow to zero and round. */
+ category = fcNormal;
zeroSignificand();
fs = normalize(rounding_mode, lfLessThanHalf);
// exponent = 0..0
// significand = 10..0
+ Val.category = fcNormal;
Val.zeroSignificand();
Val.sign = Negative;
Val.exponent = Sem.minExponent;
// Set FormatPrecision if zero. We want to do this before we
// truncate trailing zeros, as those are part of the precision.
if (!FormatPrecision) {
- // It's an interesting question whether to use the nominal
- // precision or the active precision here for denormals.
-
- // FormatPrecision = ceil(significandBits / lg_2(10))
- FormatPrecision = (semantics->precision * 59 + 195) / 196;
+ // We use enough digits so the number can be round-tripped back to an
+ // APFloat. The formula comes from "How to Print Floating-Point Numbers
+ // Accurately" by Steele and White.
+ // FIXME: Using a formula based purely on the precision is conservative;
+ // we can print fewer digits depending on the actual value being printed.
+
+ // FormatPrecision = 2 + floor(significandBits / lg_2(10))
+ FormatPrecision = 2 + semantics->precision * 59 / 196;
}
// Ignore trailing binary zeros.
projects / oota-llvm.git / blobdiff