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//===-- lib/Evaluate/real.cpp ---------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "flang/Evaluate/real.h"
#include "int-power.h"
#include "flang/Common/idioms.h"
#include "flang/Decimal/decimal.h"
#include "flang/Parser/characters.h"
#include "llvm/Support/raw_ostream.h"
#include <limits>
namespace Fortran::evaluate::value {
template <typename W, int P> Relation Real<W, P>::Compare(const Real &y) const {
if (IsNotANumber() || y.IsNotANumber()) { // NaN vs x, x vs NaN
return Relation::Unordered;
} else if (IsInfinite()) {
if (y.IsInfinite()) {
if (IsNegative()) { // -Inf vs +/-Inf
return y.IsNegative() ? Relation::Equal : Relation::Less;
} else { // +Inf vs +/-Inf
return y.IsNegative() ? Relation::Greater : Relation::Equal;
}
} else { // +/-Inf vs finite
return IsNegative() ? Relation::Less : Relation::Greater;
}
} else if (y.IsInfinite()) { // finite vs +/-Inf
return y.IsNegative() ? Relation::Greater : Relation::Less;
} else { // two finite numbers
bool isNegative{IsNegative()};
if (isNegative != y.IsNegative()) {
if (word_.IOR(y.word_).IBCLR(bits - 1).IsZero()) {
return Relation::Equal; // +/-0.0 == -/+0.0
} else {
return isNegative ? Relation::Less : Relation::Greater;
}
} else {
// same sign
Ordering order{evaluate::Compare(Exponent(), y.Exponent())};
if (order == Ordering::Equal) {
order = GetSignificand().CompareUnsigned(y.GetSignificand());
}
if (isNegative) {
order = Reverse(order);
}
return RelationFromOrdering(order);
}
}
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::Add(
const Real &y, Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber() || y.IsNotANumber()) {
result.value = NotANumber(); // NaN + x -> NaN
if (IsSignalingNaN() || y.IsSignalingNaN()) {
result.flags.set(RealFlag::InvalidArgument);
}
return result;
}
bool isNegative{IsNegative()};
bool yIsNegative{y.IsNegative()};
if (IsInfinite()) {
if (y.IsInfinite()) {
if (isNegative == yIsNegative) {
result.value = *this; // +/-Inf + +/-Inf -> +/-Inf
} else {
result.value = NotANumber(); // +/-Inf + -/+Inf -> NaN
result.flags.set(RealFlag::InvalidArgument);
}
} else {
result.value = *this; // +/-Inf + x -> +/-Inf
}
return result;
}
if (y.IsInfinite()) {
result.value = y; // x + +/-Inf -> +/-Inf
return result;
}
int exponent{Exponent()};
int yExponent{y.Exponent()};
if (exponent < yExponent) {
// y is larger in magnitude; simplify by reversing operands
return y.Add(*this, rounding);
}
if (exponent == yExponent && isNegative != yIsNegative) {
Ordering order{GetSignificand().CompareUnsigned(y.GetSignificand())};
if (order == Ordering::Less) {
// Same exponent, opposite signs, and y is larger in magnitude
return y.Add(*this, rounding);
}
if (order == Ordering::Equal) {
// x + (-x) -> +0.0 unless rounding is directed downwards
if (rounding.mode == common::RoundingMode::Down) {
result.value = NegativeZero();
}
return result;
}
}
// Our exponent is greater than y's, or the exponents match and y is not
// of the opposite sign and greater magnitude. So (x+y) will have the
// same sign as x.
Fraction fraction{GetFraction()};
Fraction yFraction{y.GetFraction()};
int rshift = exponent - yExponent;
if (exponent > 0 && yExponent == 0) {
--rshift; // correct overshift when only y is subnormal
}
RoundingBits roundingBits{yFraction, rshift};
yFraction = yFraction.SHIFTR(rshift);
bool carry{false};
if (isNegative != yIsNegative) {
// Opposite signs: subtract via addition of two's complement of y and
// the rounding bits.
yFraction = yFraction.NOT();
carry = roundingBits.Negate();
}
auto sum{fraction.AddUnsigned(yFraction, carry)};
fraction = sum.value;
if (isNegative == yIsNegative && sum.carry) {
roundingBits.ShiftRight(sum.value.BTEST(0));
fraction = fraction.SHIFTR(1).IBSET(fraction.bits - 1);
++exponent;
}
NormalizeAndRound(
result, isNegative, exponent, fraction, rounding, roundingBits);
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::Multiply(
const Real &y, Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber() || y.IsNotANumber()) {
result.value = NotANumber(); // NaN * x -> NaN
if (IsSignalingNaN() || y.IsSignalingNaN()) {
result.flags.set(RealFlag::InvalidArgument);
}
} else {
bool isNegative{IsNegative() != y.IsNegative()};
if (IsInfinite() || y.IsInfinite()) {
if (IsZero() || y.IsZero()) {
result.value = NotANumber(); // 0 * Inf -> NaN
result.flags.set(RealFlag::InvalidArgument);
} else {
result.value = Infinity(isNegative);
}
} else {
auto product{GetFraction().MultiplyUnsigned(y.GetFraction())};
std::int64_t exponent{CombineExponents(y, false)};
if (exponent < 1) {
int rshift = 1 - exponent;
exponent = 1;
bool sticky{false};
if (rshift >= product.upper.bits + product.lower.bits) {
sticky = !product.lower.IsZero() || !product.upper.IsZero();
} else if (rshift >= product.lower.bits) {
sticky = !product.lower.IsZero() ||
!product.upper
.IAND(product.upper.MASKR(rshift - product.lower.bits))
.IsZero();
} else {
sticky = !product.lower.IAND(product.lower.MASKR(rshift)).IsZero();
}
product.lower = product.lower.SHIFTRWithFill(product.upper, rshift);
product.upper = product.upper.SHIFTR(rshift);
if (sticky) {
product.lower = product.lower.IBSET(0);
}
}
int leadz{product.upper.LEADZ()};
if (leadz >= product.upper.bits) {
leadz += product.lower.LEADZ();
}
int lshift{leadz};
if (lshift > exponent - 1) {
lshift = exponent - 1;
}
exponent -= lshift;
product.upper = product.upper.SHIFTLWithFill(product.lower, lshift);
product.lower = product.lower.SHIFTL(lshift);
RoundingBits roundingBits{product.lower, product.lower.bits};
NormalizeAndRound(result, isNegative, exponent, product.upper, rounding,
roundingBits, true /*multiply*/);
}
}
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::Divide(
const Real &y, Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber() || y.IsNotANumber()) {
result.value = NotANumber(); // NaN / x -> NaN, x / NaN -> NaN
if (IsSignalingNaN() || y.IsSignalingNaN()) {
result.flags.set(RealFlag::InvalidArgument);
}
} else {
bool isNegative{IsNegative() != y.IsNegative()};
if (IsInfinite()) {
if (y.IsInfinite()) {
result.value = NotANumber(); // Inf/Inf -> NaN
result.flags.set(RealFlag::InvalidArgument);
} else { // Inf/x -> Inf, Inf/0 -> Inf
result.value = Infinity(isNegative);
}
} else if (y.IsZero()) {
if (IsZero()) { // 0/0 -> NaN
result.value = NotANumber();
result.flags.set(RealFlag::InvalidArgument);
} else { // x/0 -> Inf, Inf/0 -> Inf
result.value = Infinity(isNegative);
result.flags.set(RealFlag::DivideByZero);
}
} else if (IsZero() || y.IsInfinite()) { // 0/x, x/Inf -> 0
if (isNegative) {
result.value = NegativeZero();
}
} else {
// dividend and divisor are both finite and nonzero numbers
Fraction top{GetFraction()}, divisor{y.GetFraction()};
std::int64_t exponent{CombineExponents(y, true)};
Fraction quotient;
bool msb{false};
if (!top.BTEST(top.bits - 1) || !divisor.BTEST(divisor.bits - 1)) {
// One or two subnormals
int topLshift{top.LEADZ()};
top = top.SHIFTL(topLshift);
int divisorLshift{divisor.LEADZ()};
divisor = divisor.SHIFTL(divisorLshift);
exponent += divisorLshift - topLshift;
}
for (int j{1}; j <= quotient.bits; ++j) {
if (NextQuotientBit(top, msb, divisor)) {
quotient = quotient.IBSET(quotient.bits - j);
}
}
bool guard{NextQuotientBit(top, msb, divisor)};
bool round{NextQuotientBit(top, msb, divisor)};
bool sticky{msb || !top.IsZero()};
RoundingBits roundingBits{guard, round, sticky};
if (exponent < 1) {
std::int64_t rshift{1 - exponent};
for (; rshift > 0; --rshift) {
roundingBits.ShiftRight(quotient.BTEST(0));
quotient = quotient.SHIFTR(1);
}
exponent = 1;
}
NormalizeAndRound(
result, isNegative, exponent, quotient, rounding, roundingBits);
}
}
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::SQRT(Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber()) {
result.value = NotANumber();
if (IsSignalingNaN()) {
result.flags.set(RealFlag::InvalidArgument);
}
} else if (IsNegative()) {
if (IsZero()) {
// SQRT(-0) == -0 in IEEE-754.
result.value = NegativeZero();
} else {
result.flags.set(RealFlag::InvalidArgument);
result.value = NotANumber();
}
} else if (IsInfinite()) {
// SQRT(+Inf) == +Inf
result.value = Infinity(false);
} else if (IsZero()) {
result.value = PositiveZero();
} else {
int expo{UnbiasedExponent()};
if (expo < -1 || expo > 1) {
// Reduce the range to [0.5 .. 4.0) by dividing by an integral power
// of four to avoid trouble with very large and very small values
// (esp. truncation of subnormals).
// SQRT(2**(2a) * x) = SQRT(2**(2a)) * SQRT(x) = 2**a * SQRT(x)
Real scaled;
int adjust{expo / 2};
scaled.Normalize(false, expo - 2 * adjust + exponentBias, GetFraction());
result = scaled.SQRT(rounding);
result.value.Normalize(false,
result.value.UnbiasedExponent() + adjust + exponentBias,
result.value.GetFraction());
return result;
}
// (-1) <= expo <= 1; use it as a shift to set the desired square.
using Extended = typename value::Integer<(binaryPrecision + 2)>;
Extended goal{
Extended::ConvertUnsigned(GetFraction()).value.SHIFTL(expo + 1)};
// Calculate the exact square root by maximizing a value whose square
// does not exceed the goal. Use two extra bits of precision for
// rounding.
bool sticky{true};
Extended extFrac{};
for (int bit{Extended::bits - 1}; bit >= 0; --bit) {
Extended next{extFrac.IBSET(bit)};
auto squared{next.MultiplyUnsigned(next)};
auto cmp{squared.upper.CompareUnsigned(goal)};
if (cmp == Ordering::Less) {
extFrac = next;
} else if (cmp == Ordering::Equal && squared.lower.IsZero()) {
extFrac = next;
sticky = false;
break; // exact result
}
}
RoundingBits roundingBits{extFrac.BTEST(1), extFrac.BTEST(0), sticky};
NormalizeAndRound(result, false, exponentBias,
Fraction::ConvertUnsigned(extFrac.SHIFTR(2)).value, rounding,
roundingBits);
}
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::NEAREST(bool upward) const {
ValueWithRealFlags<Real> result;
if (IsFinite()) {
Fraction fraction{GetFraction()};
int expo{Exponent()};
Fraction one{1};
Fraction nearest;
bool isNegative{IsNegative()};
if (upward != isNegative) { // upward in magnitude
auto next{fraction.AddUnsigned(one)};
if (next.carry) {
++expo;
nearest = Fraction::Least(); // MSB only
} else {
nearest = next.value;
}
} else { // downward in magnitude
if (IsZero()) {
nearest = 1; // smallest magnitude negative subnormal
isNegative = !isNegative;
} else {
auto sub1{fraction.SubtractSigned(one)};
if (sub1.overflow && expo > 1) {
nearest = Fraction{0}.NOT();
--expo;
} else {
nearest = sub1.value;
}
}
}
result.flags = result.value.Normalize(isNegative, expo, nearest);
} else {
result.flags.set(RealFlag::InvalidArgument);
result.value = *this;
}
return result;
}
// HYPOT(x,y) = SQRT(x**2 + y**2) by definition, but those squared intermediate
// values are susceptible to over/underflow when computed naively.
// Assuming that x>=y, calculate instead:
// HYPOT(x,y) = SQRT(x**2 * (1+(y/x)**2))
// = ABS(x) * SQRT(1+(y/x)**2)
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::HYPOT(
const Real &y, Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber() || y.IsNotANumber()) {
result.flags.set(RealFlag::InvalidArgument);
result.value = NotANumber();
} else if (ABS().Compare(y.ABS()) == Relation::Less) {
return y.HYPOT(*this);
} else if (IsZero()) {
return result; // x==y==0
} else {
auto yOverX{y.Divide(*this, rounding)}; // y/x
bool inexact{yOverX.flags.test(RealFlag::Inexact)};
auto squared{yOverX.value.Multiply(yOverX.value, rounding)}; // (y/x)**2
inexact |= squared.flags.test(RealFlag::Inexact);
Real one;
one.Normalize(false, exponentBias, Fraction::MASKL(1)); // 1.0
auto sum{squared.value.Add(one, rounding)}; // 1.0 + (y/x)**2
inexact |= sum.flags.test(RealFlag::Inexact);
auto sqrt{sum.value.SQRT()};
inexact |= sqrt.flags.test(RealFlag::Inexact);
result = sqrt.value.Multiply(ABS(), rounding);
if (inexact) {
result.flags.set(RealFlag::Inexact);
}
}
return result;
}
// MOD(x,y) = x - AINT(x/y)*y in the standard; unfortunately, this definition
// can be pretty inaccurate when x is much larger than y in magnitude due to
// cancellation. Implement instead with (essentially) arbitrary precision
// long division, discarding the quotient and returning the remainder.
// See runtime/numeric.cpp for more details.
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::MOD(
const Real &p, Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber() || p.IsNotANumber() || IsInfinite()) {
result.flags.set(RealFlag::InvalidArgument);
result.value = NotANumber();
} else if (p.IsZero()) {
result.flags.set(RealFlag::DivideByZero);
result.value = NotANumber();
} else if (p.IsInfinite()) {
result.value = *this;
} else {
result.value = ABS();
auto pAbs{p.ABS()};
Real half, adj;
half.Normalize(false, exponentBias - 1, Fraction::MASKL(1)); // 0.5
for (adj.Normalize(false, Exponent(), pAbs.GetFraction());
result.value.Compare(pAbs) != Relation::Less;
adj = adj.Multiply(half).value) {
if (result.value.Compare(adj) != Relation::Less) {
result.value =
result.value.Subtract(adj, rounding).AccumulateFlags(result.flags);
if (result.value.IsZero()) {
break;
}
}
}
if (IsNegative()) {
result.value = result.value.Negate();
}
}
return result;
}
// MODULO(x,y) = x - FLOOR(x/y)*y in the standard; here, it is defined
// in terms of MOD() with adjustment of the result.
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::MODULO(
const Real &p, Rounding rounding) const {
ValueWithRealFlags<Real> result{MOD(p, rounding)};
if (IsNegative() != p.IsNegative()) {
if (result.value.IsZero()) {
result.value = result.value.Negate();
} else {
result.value =
result.value.Add(p, rounding).AccumulateFlags(result.flags);
}
}
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::DIM(
const Real &y, Rounding rounding) const {
ValueWithRealFlags<Real> result;
if (IsNotANumber() || y.IsNotANumber()) {
result.flags.set(RealFlag::InvalidArgument);
result.value = NotANumber();
} else if (Compare(y) == Relation::Greater) {
result = Subtract(y, rounding);
} else {
// result is already zero
}
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::ToWholeNumber(
common::RoundingMode mode) const {
ValueWithRealFlags<Real> result{*this};
if (IsNotANumber()) {
result.flags.set(RealFlag::InvalidArgument);
result.value = NotANumber();
} else if (IsInfinite()) {
result.flags.set(RealFlag::Overflow);
} else {
constexpr int noClipExponent{exponentBias + binaryPrecision - 1};
if (Exponent() < noClipExponent) {
Real adjust; // ABS(EPSILON(adjust)) == 0.5
adjust.Normalize(IsSignBitSet(), noClipExponent, Fraction::MASKL(1));
// Compute ival=(*this + adjust), losing any fractional bits; keep flags
result = Add(adjust, Rounding{mode});
result.flags.reset(RealFlag::Inexact); // result *is* exact
// Return (ival-adjust) with original sign in case we've generated a zero.
result.value =
result.value.Subtract(adjust, Rounding{common::RoundingMode::ToZero})
.value.SIGN(*this);
}
}
return result;
}
template <typename W, int P>
RealFlags Real<W, P>::Normalize(bool negative, int exponent,
const Fraction &fraction, Rounding rounding, RoundingBits *roundingBits) {
int lshift{fraction.LEADZ()};
if (lshift == fraction.bits /* fraction is zero */ &&
(!roundingBits || roundingBits->empty())) {
// No fraction, no rounding bits -> +/-0.0
exponent = lshift = 0;
} else if (lshift < exponent) {
exponent -= lshift;
} else if (exponent > 0) {
lshift = exponent - 1;
exponent = 0;
} else if (lshift == 0) {
exponent = 1;
} else {
lshift = 0;
}
if (exponent >= maxExponent) {
// Infinity or overflow
if (rounding.mode == common::RoundingMode::TiesToEven ||
rounding.mode == common::RoundingMode::TiesAwayFromZero ||
(rounding.mode == common::RoundingMode::Up && !negative) ||
(rounding.mode == common::RoundingMode::Down && negative)) {
word_ = Word{maxExponent}.SHIFTL(significandBits); // Inf
} else {
// directed rounding: round to largest finite value rather than infinity
// (x86 does this, not sure whether it's standard behavior)
word_ = Word{word_.MASKR(word_.bits - 1)}.IBCLR(significandBits);
}
if (negative) {
word_ = word_.IBSET(bits - 1);
}
RealFlags flags{RealFlag::Overflow};
if (!fraction.IsZero()) {
flags.set(RealFlag::Inexact);
}
return flags;
}
word_ = Word::ConvertUnsigned(fraction).value;
if (lshift > 0) {
word_ = word_.SHIFTL(lshift);
if (roundingBits) {
for (; lshift > 0; --lshift) {
if (roundingBits->ShiftLeft()) {
word_ = word_.IBSET(lshift - 1);
}
}
}
}
if constexpr (isImplicitMSB) {
word_ = word_.IBCLR(significandBits);
}
word_ = word_.IOR(Word{exponent}.SHIFTL(significandBits));
if (negative) {
word_ = word_.IBSET(bits - 1);
}
return {};
}
template <typename W, int P>
RealFlags Real<W, P>::Round(
Rounding rounding, const RoundingBits &bits, bool multiply) {
int origExponent{Exponent()};
RealFlags flags;
bool inexact{!bits.empty()};
if (inexact) {
flags.set(RealFlag::Inexact);
}
if (origExponent < maxExponent &&
bits.MustRound(rounding, IsNegative(), word_.BTEST(0) /* is odd */)) {
typename Fraction::ValueWithCarry sum{
GetFraction().AddUnsigned(Fraction{}, true)};
int newExponent{origExponent};
if (sum.carry) {
// The fraction was all ones before rounding; sum.value is now zero
sum.value = sum.value.IBSET(binaryPrecision - 1);
if (++newExponent >= maxExponent) {
flags.set(RealFlag::Overflow); // rounded away to an infinity
}
}
flags |= Normalize(IsNegative(), newExponent, sum.value);
}
if (inexact && origExponent == 0) {
// inexact subnormal input: signal Underflow unless in an x86-specific
// edge case
if (rounding.x86CompatibleBehavior && Exponent() != 0 && multiply &&
bits.sticky() &&
(bits.guard() ||
(rounding.mode != common::RoundingMode::Up &&
rounding.mode != common::RoundingMode::Down))) {
// x86 edge case in which Underflow fails to signal when a subnormal
// inexact multiplication product rounds to a normal result when
// the guard bit is set or we're not using directed rounding
} else {
flags.set(RealFlag::Underflow);
}
}
return flags;
}
template <typename W, int P>
void Real<W, P>::NormalizeAndRound(ValueWithRealFlags<Real> &result,
bool isNegative, int exponent, const Fraction &fraction, Rounding rounding,
RoundingBits roundingBits, bool multiply) {
result.flags |= result.value.Normalize(
isNegative, exponent, fraction, rounding, &roundingBits);
result.flags |= result.value.Round(rounding, roundingBits, multiply);
}
inline enum decimal::FortranRounding MapRoundingMode(
common::RoundingMode rounding) {
switch (rounding) {
case common::RoundingMode::TiesToEven:
break;
case common::RoundingMode::ToZero:
return decimal::RoundToZero;
case common::RoundingMode::Down:
return decimal::RoundDown;
case common::RoundingMode::Up:
return decimal::RoundUp;
case common::RoundingMode::TiesAwayFromZero:
return decimal::RoundCompatible;
}
return decimal::RoundNearest; // dodge gcc warning about lack of result
}
inline RealFlags MapFlags(decimal::ConversionResultFlags flags) {
RealFlags result;
if (flags & decimal::Overflow) {
result.set(RealFlag::Overflow);
}
if (flags & decimal::Inexact) {
result.set(RealFlag::Inexact);
}
if (flags & decimal::Invalid) {
result.set(RealFlag::InvalidArgument);
}
return result;
}
template <typename W, int P>
ValueWithRealFlags<Real<W, P>> Real<W, P>::Read(
const char *&p, Rounding rounding) {
auto converted{
decimal::ConvertToBinary<P>(p, MapRoundingMode(rounding.mode))};
const auto *value{reinterpret_cast<Real<W, P> *>(&converted.binary)};
return {*value, MapFlags(converted.flags)};
}
template <typename W, int P> std::string Real<W, P>::DumpHexadecimal() const {
if (IsNotANumber()) {
return "NaN0x"s + word_.Hexadecimal();
} else if (IsNegative()) {
return "-"s + Negate().DumpHexadecimal();
} else if (IsInfinite()) {
return "Inf"s;
} else if (IsZero()) {
return "0.0"s;
} else {
Fraction frac{GetFraction()};
std::string result{"0x"};
char intPart = '0' + frac.BTEST(frac.bits - 1);
result += intPart;
result += '.';
int trailz{frac.TRAILZ()};
if (trailz >= frac.bits - 1) {
result += '0';
} else {
int remainingBits{frac.bits - 1 - trailz};
int wholeNybbles{remainingBits / 4};
int lostBits{remainingBits - 4 * wholeNybbles};
if (wholeNybbles > 0) {
std::string fracHex{frac.SHIFTR(trailz + lostBits)
.IAND(frac.MASKR(4 * wholeNybbles))
.Hexadecimal()};
std::size_t field = wholeNybbles;
if (fracHex.size() < field) {
result += std::string(field - fracHex.size(), '0');
}
result += fracHex;
}
if (lostBits > 0) {
result += frac.SHIFTR(trailz)
.IAND(frac.MASKR(lostBits))
.SHIFTL(4 - lostBits)
.Hexadecimal();
}
}
result += 'p';
int exponent = Exponent() - exponentBias;
if (intPart == '0') {
exponent += 1;
}
result += Integer<32>{exponent}.SignedDecimal();
return result;
}
}
template <typename W, int P>
llvm::raw_ostream &Real<W, P>::AsFortran(
llvm::raw_ostream &o, int kind, bool minimal) const {
if (IsNotANumber()) {
o << "(0._" << kind << "/0.)";
} else if (IsInfinite()) {
if (IsNegative()) {
o << "(-1._" << kind << "/0.)";
} else {
o << "(1._" << kind << "/0.)";
}
} else {
using B = decimal::BinaryFloatingPointNumber<P>;
B value{word_.template ToUInt<typename B::RawType>()};
char buffer[common::MaxDecimalConversionDigits(P) +
EXTRA_DECIMAL_CONVERSION_SPACE];
decimal::DecimalConversionFlags flags{}; // default: exact representation
if (minimal) {
flags = decimal::Minimize;
}
auto result{decimal::ConvertToDecimal<P>(buffer, sizeof buffer, flags,
static_cast<int>(sizeof buffer), decimal::RoundNearest, value)};
const char *p{result.str};
if (DEREF(p) == '-' || *p == '+') {
o << *p++;
}
int expo{result.decimalExponent};
if (*p != '0') {
--expo;
}
o << *p << '.' << (p + 1);
if (expo != 0) {
o << 'e' << expo;
}
o << '_' << kind;
}
return o;
}
// 16.9.180
template <typename W, int P> Real<W, P> Real<W, P>::RRSPACING() const {
if (IsNotANumber()) {
return *this;
} else if (IsInfinite()) {
return NotANumber();
} else {
Real result;
result.Normalize(false, binaryPrecision + exponentBias - 1, GetFraction());
return result;
}
}
// 16.9.180
template <typename W, int P> Real<W, P> Real<W, P>::SPACING() const {
if (IsNotANumber()) {
return *this;
} else if (IsInfinite()) {
return NotANumber();
} else if (IsZero() || IsSubnormal()) {
return TINY(); // mandated by standard
} else {
Real result;
result.Normalize(false, Exponent(), Fraction::MASKR(1));
return result.IsZero() ? TINY() : result;
}
}
// 16.9.171
template <typename W, int P>
Real<W, P> Real<W, P>::SET_EXPONENT(std::int64_t expo) const {
if (IsNotANumber()) {
return *this;
} else if (IsInfinite()) {
return NotANumber();
} else if (IsZero()) {
return *this;
} else {
return SCALE(Integer<64>(expo - UnbiasedExponent() - 1)).value;
}
}
// 16.9.171
template <typename W, int P> Real<W, P> Real<W, P>::FRACTION() const {
return SET_EXPONENT(0);
}
template class Real<Integer<16>, 11>;
template class Real<Integer<16>, 8>;
template class Real<Integer<32>, 24>;
template class Real<Integer<64>, 53>;
template class Real<Integer<80>, 64>;
template class Real<Integer<128>, 113>;
} // namespace Fortran::evaluate::value