//===----------------------------------------------------------------------===//
#include "llvm/ADT/APFloat.h"
-#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/StringRef.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include <cstring>
+#include <limits.h>
using namespace llvm;
/* Number of bits in the significand. This includes the integer
bit. */
unsigned int precision;
-
- /* True if arithmetic is supported. */
- unsigned int arithmeticOK;
};
- const fltSemantics APFloat::IEEEhalf = { 15, -14, 11, true };
- const fltSemantics APFloat::IEEEsingle = { 127, -126, 24, true };
- const fltSemantics APFloat::IEEEdouble = { 1023, -1022, 53, true };
- const fltSemantics APFloat::IEEEquad = { 16383, -16382, 113, true };
- const fltSemantics APFloat::x87DoubleExtended = { 16383, -16382, 64, true };
- const fltSemantics APFloat::Bogus = { 0, 0, 0, true };
-
- // The PowerPC format consists of two doubles. It does not map cleanly
- // onto the usual format above. For now only storage of constants of
- // this type is supported, no arithmetic.
- const fltSemantics APFloat::PPCDoubleDouble = { 1023, -1022, 106, false };
+ const fltSemantics APFloat::IEEEhalf = { 15, -14, 11 };
+ const fltSemantics APFloat::IEEEsingle = { 127, -126, 24 };
+ const fltSemantics APFloat::IEEEdouble = { 1023, -1022, 53 };
+ const fltSemantics APFloat::IEEEquad = { 16383, -16382, 113 };
+ const fltSemantics APFloat::x87DoubleExtended = { 16383, -16382, 64 };
+ const fltSemantics APFloat::Bogus = { 0, 0, 0 };
+
+ /* The PowerPC format consists of two doubles. It does not map cleanly
+ onto the usual format above. It is approximated using twice the
+ mantissa bits. Note that for exponents near the double minimum,
+ we no longer can represent the full 106 mantissa bits, so those
+ will be treated as denormal numbers.
+
+ FIXME: While this approximation is equivalent to what GCC uses for
+ compile-time arithmetic on PPC double-double numbers, it is not able
+ to represent all possible values held by a PPC double-double number,
+ for example: (long double) 1.0 + (long double) 0x1p-106
+ Should this be replaced by a full emulation of PPC double-double? */
+ const fltSemantics APFloat::PPCDoubleDouble = { 1023, -1022 + 53, 53 + 53 };
/* A tight upper bound on number of parts required to hold the value
pow(5, power) is
power * 815 / (351 * integerPartWidth) + 1
-
+
However, whilst the result may require only this many parts,
because we are multiplying two values to get it, the
multiplication may require an extra part with the excess part
unsigned int r;
r = c - '0';
- if(r <= 9)
+ if (r <= 9)
return r;
r = c - 'A';
- if(r <= 5)
+ if (r <= 5)
return r + 10;
r = c - 'a';
- if(r <= 5)
+ if (r <= 5)
return r + 10;
return -1U;
}
-static inline void
-assertArithmeticOK(const llvm::fltSemantics &semantics) {
- assert(semantics.arithmeticOK
- && "Compile-time arithmetic does not support these semantics");
-}
-
/* Return the value of a decimal exponent of the form
[+-]ddddddd.
value += absExponent * 10;
if (absExponent >= overlargeExponent) {
absExponent = overlargeExponent;
+ p = end; /* outwit assert below */
break;
}
absExponent = value;
{
int unsignedExponent;
bool negative, overflow;
- int exponent;
+ int exponent = 0;
assert(p != end && "Exponent has no digits");
negative = *p == '-';
- if(*p == '-' || *p == '+') {
+ if (*p == '-' || *p == '+') {
p++;
assert(p != end && "Exponent has no digits");
}
unsignedExponent = 0;
overflow = false;
- for(; p != end; ++p) {
+ for (; p != end; ++p) {
unsigned int value;
value = decDigitValue(*p);
assert(value < 10U && "Invalid character in exponent");
unsignedExponent = unsignedExponent * 10 + value;
- if(unsignedExponent > 65535)
+ if (unsignedExponent > 32767) {
overflow = true;
+ break;
+ }
}
- if(exponentAdjustment > 65535 || exponentAdjustment < -65536)
+ if (exponentAdjustment > 32767 || exponentAdjustment < -32768)
overflow = true;
- if(!overflow) {
+ if (!overflow) {
exponent = unsignedExponent;
- if(negative)
+ if (negative)
exponent = -exponent;
exponent += exponentAdjustment;
- if(exponent > 65535 || exponent < -65536)
+ if (exponent > 32767 || exponent < -32768)
overflow = true;
}
- if(overflow)
- exponent = negative ? -65536: 65535;
+ if (overflow)
+ exponent = negative ? -32768: 32767;
return exponent;
}
{
StringRef::iterator p = begin;
*dot = end;
- while(*p == '0' && p != end)
+ while (*p == '0' && p != end)
p++;
- if(*p == '.') {
+ if (*p == '.') {
*dot = p++;
assert(end - begin != 1 && "Significand has no digits");
- while(*p == '0' && p != end)
+ while (*p == '0' && p != end)
p++;
}
/* If the first trailing digit isn't 0 or 8 we can work out the
fraction immediately. */
- if(digitValue > 8)
+ if (digitValue > 8)
return lfMoreThanHalf;
- else if(digitValue < 8 && digitValue > 0)
+ else if (digitValue < 8 && digitValue > 0)
return lfLessThanHalf;
/* Otherwise we need to find the first non-zero digit. */
- while(*p == '0')
+ while (*p == '0')
p++;
assert(p != end && "Invalid trailing hexadecimal fraction!");
/* If we ran off the end it is exactly zero or one-half, otherwise
a little more. */
- if(hexDigit == -1U)
+ if (hexDigit == -1U)
return digitValue == 0 ? lfExactlyZero: lfExactlyHalf;
else
return digitValue == 0 ? lfLessThanHalf: lfMoreThanHalf;
lsb = APInt::tcLSB(parts, partCount);
/* Note this is guaranteed true if bits == 0, or LSB == -1U. */
- if(bits <= lsb)
+ if (bits <= lsb)
return lfExactlyZero;
- if(bits == lsb + 1)
+ if (bits == lsb + 1)
return lfExactlyHalf;
- if(bits <= partCount * integerPartWidth
- && APInt::tcExtractBit(parts, bits - 1))
+ if (bits <= partCount * integerPartWidth &&
+ APInt::tcExtractBit(parts, bits - 1))
return lfMoreThanHalf;
return lfLessThanHalf;
combineLostFractions(lostFraction moreSignificant,
lostFraction lessSignificant)
{
- if(lessSignificant != lfExactlyZero) {
- if(moreSignificant == lfExactlyZero)
+ if (lessSignificant != lfExactlyZero) {
+ if (moreSignificant == lfExactlyZero)
moreSignificant = lfLessThanHalf;
- else if(moreSignificant == lfExactlyHalf)
+ else if (moreSignificant == lfExactlyHalf)
moreSignificant = lfMoreThanHalf;
}
15625, 78125 };
integerPart pow5s[maxPowerOfFiveParts * 2 + 5];
pow5s[0] = 78125 * 5;
-
+
unsigned int partsCount[16] = { 1 };
integerPart scratch[maxPowerOfFiveParts], *p1, *p2, *pow5;
unsigned int result;
semantics = ourSemantics;
count = partCount();
- if(count > 1)
+ if (count > 1)
significand.parts = new integerPart[count];
}
void
APFloat::freeSignificand()
{
- if(partCount() > 1)
+ if (partCount() > 1)
delete [] significand.parts;
}
sign = rhs.sign;
category = rhs.category;
exponent = rhs.exponent;
- sign2 = rhs.sign2;
- exponent2 = rhs.exponent2;
- if(category == fcNormal || category == fcNaN)
+ if (category == fcNormal || category == fcNaN)
copySignificand(rhs);
}
/* Make this number a NaN, with an arbitrary but deterministic value
for the significand. If double or longer, this is a signalling NaN,
which may not be ideal. If float, this is QNaN(0). */
-void
-APFloat::makeNaN(unsigned type)
+void APFloat::makeNaN(bool SNaN, bool Negative, const APInt *fill)
{
category = fcNaN;
- // FIXME: Add double and long double support for QNaN(0).
- if (semantics->precision == 24 && semantics->maxExponent == 127) {
- type |= 0x7fc00000U;
- type &= ~0x80000000U;
- } else
- type = ~0U;
- APInt::tcSet(significandParts(), type, partCount());
+ sign = Negative;
+
+ integerPart *significand = significandParts();
+ unsigned numParts = partCount();
+
+ // Set the significand bits to the fill.
+ if (!fill || fill->getNumWords() < numParts)
+ APInt::tcSet(significand, 0, numParts);
+ if (fill) {
+ APInt::tcAssign(significand, fill->getRawData(),
+ std::min(fill->getNumWords(), numParts));
+
+ // Zero out the excess bits of the significand.
+ unsigned bitsToPreserve = semantics->precision - 1;
+ unsigned part = bitsToPreserve / 64;
+ bitsToPreserve %= 64;
+ significand[part] &= ((1ULL << bitsToPreserve) - 1);
+ for (part++; part != numParts; ++part)
+ significand[part] = 0;
+ }
+
+ unsigned QNaNBit = semantics->precision - 2;
+
+ if (SNaN) {
+ // We always have to clear the QNaN bit to make it an SNaN.
+ APInt::tcClearBit(significand, QNaNBit);
+
+ // If there are no bits set in the payload, we have to set
+ // *something* to make it a NaN instead of an infinity;
+ // conventionally, this is the next bit down from the QNaN bit.
+ if (APInt::tcIsZero(significand, numParts))
+ APInt::tcSetBit(significand, QNaNBit - 1);
+ } else {
+ // We always have to set the QNaN bit to make it a QNaN.
+ APInt::tcSetBit(significand, QNaNBit);
+ }
+
+ // For x87 extended precision, we want to make a NaN, not a
+ // pseudo-NaN. Maybe we should expose the ability to make
+ // pseudo-NaNs?
+ if (semantics == &APFloat::x87DoubleExtended)
+ APInt::tcSetBit(significand, QNaNBit + 1);
+}
+
+APFloat APFloat::makeNaN(const fltSemantics &Sem, bool SNaN, bool Negative,
+ const APInt *fill) {
+ APFloat value(Sem, uninitialized);
+ value.makeNaN(SNaN, Negative, fill);
+ return value;
}
APFloat &
APFloat::operator=(const APFloat &rhs)
{
- if(this != &rhs) {
- if(semantics != rhs.semantics) {
+ if (this != &rhs) {
+ if (semantics != rhs.semantics) {
freeSignificand();
initialize(rhs.semantics);
}
return *this;
}
+bool
+APFloat::isDenormal() const {
+ return isNormal() && (exponent == semantics->minExponent) &&
+ (APInt::tcExtractBit(significandParts(),
+ semantics->precision - 1) == 0);
+}
+
bool
APFloat::bitwiseIsEqual(const APFloat &rhs) const {
if (this == &rhs)
category != rhs.category ||
sign != rhs.sign)
return false;
- if (semantics==(const llvm::fltSemantics*)&PPCDoubleDouble &&
- sign2 != rhs.sign2)
- return false;
if (category==fcZero || category==fcInfinity)
return true;
else if (category==fcNormal && exponent!=rhs.exponent)
return false;
- else if (semantics==(const llvm::fltSemantics*)&PPCDoubleDouble &&
- exponent2!=rhs.exponent2)
- return false;
else {
int i= partCount();
const integerPart* p=significandParts();
}
}
-APFloat::APFloat(const fltSemantics &ourSemantics, integerPart value)
-{
- assertArithmeticOK(ourSemantics);
+APFloat::APFloat(const fltSemantics &ourSemantics, integerPart value) {
initialize(&ourSemantics);
sign = 0;
zeroSignificand();
}
APFloat::APFloat(const fltSemantics &ourSemantics) {
- assertArithmeticOK(ourSemantics);
initialize(&ourSemantics);
category = fcZero;
sign = false;
}
+APFloat::APFloat(const fltSemantics &ourSemantics, uninitializedTag tag) {
+ // Allocates storage if necessary but does not initialize it.
+ initialize(&ourSemantics);
+}
APFloat::APFloat(const fltSemantics &ourSemantics,
- fltCategory ourCategory, bool negative, unsigned type)
-{
- assertArithmeticOK(ourSemantics);
+ fltCategory ourCategory, bool negative) {
initialize(&ourSemantics);
category = ourCategory;
sign = negative;
if (category == fcNormal)
category = fcZero;
else if (ourCategory == fcNaN)
- makeNaN(type);
+ makeNaN();
}
-APFloat::APFloat(const fltSemantics &ourSemantics, const StringRef& text)
-{
- assertArithmeticOK(ourSemantics);
+APFloat::APFloat(const fltSemantics &ourSemantics, StringRef text) {
initialize(&ourSemantics);
convertFromString(text, rmNearestTiesToEven);
}
-APFloat::APFloat(const APFloat &rhs)
-{
+APFloat::APFloat(const APFloat &rhs) {
initialize(rhs.semantics);
assign(rhs);
}
/* Our callers should never cause us to overflow. */
assert(carry == 0);
+ (void)carry;
}
/* Add the significand of the RHS. Returns the carry flag. */
precision = semantics->precision;
newPartsCount = partCountForBits(precision * 2);
- if(newPartsCount > 4)
+ if (newPartsCount > 4)
fullSignificand = new integerPart[newPartsCount];
else
fullSignificand = scratch;
omsb = APInt::tcMSB(fullSignificand, newPartsCount) + 1;
exponent += rhs.exponent;
- if(addend) {
+ if (addend) {
Significand savedSignificand = significand;
const fltSemantics *savedSemantics = semantics;
fltSemantics extendedSemantics;
/* Normalize our MSB. */
extendedPrecision = precision + precision - 1;
- if(omsb != extendedPrecision)
- {
- APInt::tcShiftLeft(fullSignificand, newPartsCount,
- extendedPrecision - omsb);
- exponent -= extendedPrecision - omsb;
- }
+ if (omsb != extendedPrecision) {
+ APInt::tcShiftLeft(fullSignificand, newPartsCount,
+ extendedPrecision - omsb);
+ exponent -= extendedPrecision - omsb;
+ }
/* Create new semantics. */
extendedSemantics = *semantics;
extendedSemantics.precision = extendedPrecision;
- if(newPartsCount == 1)
+ if (newPartsCount == 1)
significand.part = fullSignificand[0];
else
significand.parts = fullSignificand;
APFloat extendedAddend(*addend);
status = extendedAddend.convert(extendedSemantics, rmTowardZero, &ignored);
assert(status == opOK);
+ (void)status;
lost_fraction = addOrSubtractSignificand(extendedAddend, false);
/* Restore our state. */
- if(newPartsCount == 1)
+ if (newPartsCount == 1)
fullSignificand[0] = significand.part;
significand = savedSignificand;
semantics = savedSemantics;
exponent -= (precision - 1);
- if(omsb > precision) {
+ if (omsb > precision) {
unsigned int bits, significantParts;
lostFraction lf;
APInt::tcAssign(lhsSignificand, fullSignificand, partsCount);
- if(newPartsCount > 4)
+ if (newPartsCount > 4)
delete [] fullSignificand;
return lost_fraction;
rhsSignificand = rhs.significandParts();
partsCount = partCount();
- if(partsCount > 2)
+ if (partsCount > 2)
dividend = new integerPart[partsCount * 2];
else
dividend = scratch;
divisor = dividend + partsCount;
/* Copy the dividend and divisor as they will be modified in-place. */
- for(i = 0; i < partsCount; i++) {
+ for (i = 0; i < partsCount; i++) {
dividend[i] = lhsSignificand[i];
divisor[i] = rhsSignificand[i];
lhsSignificand[i] = 0;
/* Normalize the divisor. */
bit = precision - APInt::tcMSB(divisor, partsCount) - 1;
- if(bit) {
+ if (bit) {
exponent += bit;
APInt::tcShiftLeft(divisor, partsCount, bit);
}
/* Normalize the dividend. */
bit = precision - APInt::tcMSB(dividend, partsCount) - 1;
- if(bit) {
+ if (bit) {
exponent -= bit;
APInt::tcShiftLeft(dividend, partsCount, bit);
}
/* Ensure the dividend >= divisor initially for the loop below.
Incidentally, this means that the division loop below is
guaranteed to set the integer bit to one. */
- if(APInt::tcCompare(dividend, divisor, partsCount) < 0) {
+ if (APInt::tcCompare(dividend, divisor, partsCount) < 0) {
exponent--;
APInt::tcShiftLeft(dividend, partsCount, 1);
assert(APInt::tcCompare(dividend, divisor, partsCount) >= 0);
}
/* Long division. */
- for(bit = precision; bit; bit -= 1) {
- if(APInt::tcCompare(dividend, divisor, partsCount) >= 0) {
+ for (bit = precision; bit; bit -= 1) {
+ if (APInt::tcCompare(dividend, divisor, partsCount) >= 0) {
APInt::tcSubtract(dividend, divisor, 0, partsCount);
APInt::tcSetBit(lhsSignificand, bit - 1);
}
/* Figure out the lost fraction. */
int cmp = APInt::tcCompare(dividend, divisor, partsCount);
- if(cmp > 0)
+ if (cmp > 0)
lost_fraction = lfMoreThanHalf;
- else if(cmp == 0)
+ else if (cmp == 0)
lost_fraction = lfExactlyHalf;
- else if(APInt::tcIsZero(dividend, partsCount))
+ else if (APInt::tcIsZero(dividend, partsCount))
lost_fraction = lfExactlyZero;
else
lost_fraction = lfLessThanHalf;
- if(partsCount > 2)
+ if (partsCount > 2)
delete [] dividend;
return lost_fraction;
{
assert(bits < semantics->precision);
- if(bits) {
+ if (bits) {
unsigned int partsCount = partCount();
APInt::tcShiftLeft(significandParts(), partsCount, bits);
/* If exponents are equal, do an unsigned bignum comparison of the
significands. */
- if(compare == 0)
+ if (compare == 0)
compare = APInt::tcCompare(significandParts(), rhs.significandParts(),
partCount());
- if(compare > 0)
+ if (compare > 0)
return cmpGreaterThan;
- else if(compare < 0)
+ else if (compare < 0)
return cmpLessThan;
else
return cmpEqual;
APFloat::handleOverflow(roundingMode rounding_mode)
{
/* Infinity? */
- if(rounding_mode == rmNearestTiesToEven
- || rounding_mode == rmNearestTiesToAway
- || (rounding_mode == rmTowardPositive && !sign)
- || (rounding_mode == rmTowardNegative && sign))
- {
- category = fcInfinity;
- return (opStatus) (opOverflow | opInexact);
- }
+ if (rounding_mode == rmNearestTiesToEven ||
+ rounding_mode == rmNearestTiesToAway ||
+ (rounding_mode == rmTowardPositive && !sign) ||
+ (rounding_mode == rmTowardNegative && sign)) {
+ category = fcInfinity;
+ return (opStatus) (opOverflow | opInexact);
+ }
/* Otherwise we become the largest finite number. */
category = fcNormal;
assert(lost_fraction != lfExactlyZero);
switch (rounding_mode) {
- default:
- llvm_unreachable(0);
-
case rmNearestTiesToAway:
return lost_fraction == lfExactlyHalf || lost_fraction == lfMoreThanHalf;
case rmNearestTiesToEven:
- if(lost_fraction == lfMoreThanHalf)
+ if (lost_fraction == lfMoreThanHalf)
return true;
/* Our zeroes don't have a significand to test. */
- if(lost_fraction == lfExactlyHalf && category != fcZero)
+ if (lost_fraction == lfExactlyHalf && category != fcZero)
return APInt::tcExtractBit(significandParts(), bit);
return false;
case rmTowardNegative:
return sign == true;
}
+ llvm_unreachable("Invalid rounding mode found");
}
APFloat::opStatus
unsigned int omsb; /* One, not zero, based MSB. */
int exponentChange;
- if(category != fcNormal)
+ if (category != fcNormal)
return opOK;
/* Before rounding normalize the exponent of fcNormal numbers. */
omsb = significandMSB() + 1;
- if(omsb) {
+ if (omsb) {
/* OMSB is numbered from 1. We want to place it in the integer
- bit numbered PRECISON if possible, with a compensating change in
+ bit numbered PRECISION if possible, with a compensating change in
the exponent. */
exponentChange = omsb - semantics->precision;
/* If the resulting exponent is too high, overflow according to
the rounding mode. */
- if(exponent + exponentChange > semantics->maxExponent)
+ if (exponent + exponentChange > semantics->maxExponent)
return handleOverflow(rounding_mode);
/* Subnormal numbers have exponent minExponent, and their MSB
is forced based on that. */
- if(exponent + exponentChange < semantics->minExponent)
+ if (exponent + exponentChange < semantics->minExponent)
exponentChange = semantics->minExponent - exponent;
/* Shifting left is easy as we don't lose precision. */
- if(exponentChange < 0) {
+ if (exponentChange < 0) {
assert(lost_fraction == lfExactlyZero);
shiftSignificandLeft(-exponentChange);
return opOK;
}
- if(exponentChange > 0) {
+ if (exponentChange > 0) {
lostFraction lf;
/* Shift right and capture any new lost fraction. */
lost_fraction = combineLostFractions(lf, lost_fraction);
/* Keep OMSB up-to-date. */
- if(omsb > (unsigned) exponentChange)
+ if (omsb > (unsigned) exponentChange)
omsb -= exponentChange;
else
omsb = 0;
/* As specified in IEEE 754, since we do not trap we do not report
underflow for exact results. */
- if(lost_fraction == lfExactlyZero) {
+ if (lost_fraction == lfExactlyZero) {
/* Canonicalize zeroes. */
- if(omsb == 0)
+ if (omsb == 0)
category = fcZero;
return opOK;
}
/* Increment the significand if we're rounding away from zero. */
- if(roundAwayFromZero(rounding_mode, lost_fraction, 0)) {
- if(omsb == 0)
+ if (roundAwayFromZero(rounding_mode, lost_fraction, 0)) {
+ if (omsb == 0)
exponent = semantics->minExponent;
incrementSignificand();
omsb = significandMSB() + 1;
/* Did the significand increment overflow? */
- if(omsb == (unsigned) semantics->precision + 1) {
+ if (omsb == (unsigned) semantics->precision + 1) {
/* Renormalize by incrementing the exponent and shifting our
significand right one. However if we already have the
maximum exponent we overflow to infinity. */
- if(exponent == semantics->maxExponent) {
+ if (exponent == semantics->maxExponent) {
category = fcInfinity;
return (opStatus) (opOverflow | opInexact);
/* The normal case - we were and are not denormal, and any
significand increment above didn't overflow. */
- if(omsb == semantics->precision)
+ if (omsb == semantics->precision)
return opInexact;
/* We have a non-zero denormal. */
assert(omsb < semantics->precision);
/* Canonicalize zeroes. */
- if(omsb == 0)
+ if (omsb == 0)
category = fcZero;
/* The fcZero case is a denormal that underflowed to zero. */
case convolve(fcInfinity, fcInfinity):
/* Differently signed infinities can only be validly
subtracted. */
- if(((sign ^ rhs.sign)!=0) != subtract) {
+ if (((sign ^ rhs.sign)!=0) != subtract) {
makeNaN();
return opInvalidOp;
}
bits = exponent - rhs.exponent;
/* Subtraction is more subtle than one might naively expect. */
- if(subtract) {
+ if (subtract) {
APFloat temp_rhs(rhs);
bool reverse;
/* Invert the lost fraction - it was on the RHS and
subtracted. */
- if(lost_fraction == lfLessThanHalf)
+ if (lost_fraction == lfLessThanHalf)
lost_fraction = lfMoreThanHalf;
- else if(lost_fraction == lfMoreThanHalf)
+ else if (lost_fraction == lfMoreThanHalf)
lost_fraction = lfLessThanHalf;
/* The code above is intended to ensure that no borrow is
necessary. */
assert(!carry);
+ (void)carry;
} else {
- if(bits > 0) {
+ if (bits > 0) {
APFloat temp_rhs(rhs);
lost_fraction = temp_rhs.shiftSignificandRight(bits);
/* We have a guard bit; generating a carry cannot happen. */
assert(!carry);
+ (void)carry;
}
return lost_fraction;
{
opStatus fs;
- assertArithmeticOK(*semantics);
-
fs = addOrSubtractSpecials(rhs, subtract);
/* This return code means it was not a simple case. */
- if(fs == opDivByZero) {
+ if (fs == opDivByZero) {
lostFraction lost_fraction;
lost_fraction = addOrSubtractSignificand(rhs, subtract);
/* If two numbers add (exactly) to zero, IEEE 754 decrees it is a
positive zero unless rounding to minus infinity, except that
adding two like-signed zeroes gives that zero. */
- if(category == fcZero) {
- if(rhs.category != fcZero || (sign == rhs.sign) == subtract)
+ if (category == fcZero) {
+ if (rhs.category != fcZero || (sign == rhs.sign) == subtract)
sign = (rounding_mode == rmTowardNegative);
}
{
opStatus fs;
- assertArithmeticOK(*semantics);
sign ^= rhs.sign;
fs = multiplySpecials(rhs);
- if(category == fcNormal) {
+ if (category == fcNormal) {
lostFraction lost_fraction = multiplySignificand(rhs, 0);
fs = normalize(rounding_mode, lost_fraction);
- if(lost_fraction != lfExactlyZero)
+ if (lost_fraction != lfExactlyZero)
fs = (opStatus) (fs | opInexact);
}
{
opStatus fs;
- assertArithmeticOK(*semantics);
sign ^= rhs.sign;
fs = divideSpecials(rhs);
- if(category == fcNormal) {
+ if (category == fcNormal) {
lostFraction lost_fraction = divideSignificand(rhs);
fs = normalize(rounding_mode, lost_fraction);
- if(lost_fraction != lfExactlyZero)
+ if (lost_fraction != lfExactlyZero)
fs = (opStatus) (fs | opInexact);
}
APFloat V = *this;
unsigned int origSign = sign;
- assertArithmeticOK(*semantics);
fs = V.divide(rhs, rmNearestTiesToEven);
if (fs == opDivByZero)
return fs;
return fs;
}
-/* Normalized llvm frem (C fmod).
+/* Normalized llvm frem (C fmod).
This is not currently correct in all cases. */
APFloat::opStatus
APFloat::mod(const APFloat &rhs, roundingMode rounding_mode)
{
opStatus fs;
- assertArithmeticOK(*semantics);
fs = modSpecials(rhs);
if (category == fcNormal && rhs.category == fcNormal) {
{
opStatus fs;
- assertArithmeticOK(*semantics);
-
/* Post-multiplication sign, before addition. */
sign ^= multiplicand.sign;
/* If and only if all arguments are normal do we need to do an
extended-precision calculation. */
- if(category == fcNormal
- && multiplicand.category == fcNormal
- && addend.category == fcNormal) {
+ if (category == fcNormal &&
+ multiplicand.category == fcNormal &&
+ addend.category == fcNormal) {
lostFraction lost_fraction;
lost_fraction = multiplySignificand(multiplicand, &addend);
fs = normalize(rounding_mode, lost_fraction);
- if(lost_fraction != lfExactlyZero)
+ if (lost_fraction != lfExactlyZero)
fs = (opStatus) (fs | opInexact);
/* If two numbers add (exactly) to zero, IEEE 754 decrees it is a
positive zero unless rounding to minus infinity, except that
adding two like-signed zeroes gives that zero. */
- if(category == fcZero && sign != addend.sign)
+ if (category == fcZero && sign != addend.sign)
sign = (rounding_mode == rmTowardNegative);
} else {
fs = multiplySpecials(multiplicand);
If we need to do the addition we can do so with normal
precision. */
- if(fs == opOK)
+ if (fs == opOK)
fs = addOrSubtract(addend, rounding_mode, false);
}
return fs;
}
+/* Rounding-mode corrrect round to integral value. */
+APFloat::opStatus APFloat::roundToIntegral(roundingMode rounding_mode) {
+ opStatus fs;
+
+ // If the exponent is large enough, we know that this value is already
+ // integral, and the arithmetic below would potentially cause it to saturate
+ // to +/-Inf. Bail out early instead.
+ if (category == fcNormal && exponent+1 >= (int)semanticsPrecision(*semantics))
+ return opOK;
+
+ // The algorithm here is quite simple: we add 2^(p-1), where p is the
+ // precision of our format, and then subtract it back off again. The choice
+ // of rounding modes for the addition/subtraction determines the rounding mode
+ // for our integral rounding as well.
+ // NOTE: When the input value is negative, we do subtraction followed by
+ // addition instead.
+ APInt IntegerConstant(NextPowerOf2(semanticsPrecision(*semantics)), 1);
+ IntegerConstant <<= semanticsPrecision(*semantics)-1;
+ APFloat MagicConstant(*semantics);
+ fs = MagicConstant.convertFromAPInt(IntegerConstant, false,
+ rmNearestTiesToEven);
+ MagicConstant.copySign(*this);
+
+ if (fs != opOK)
+ return fs;
+
+ // Preserve the input sign so that we can handle 0.0/-0.0 cases correctly.
+ bool inputSign = isNegative();
+
+ fs = add(MagicConstant, rounding_mode);
+ if (fs != opOK && fs != opInexact)
+ return fs;
+
+ fs = subtract(MagicConstant, rounding_mode);
+
+ // Restore the input sign.
+ if (inputSign != isNegative())
+ changeSign();
+
+ return fs;
+}
+
+
/* Comparison requires normalized numbers. */
APFloat::cmpResult
APFloat::compare(const APFloat &rhs) const
{
cmpResult result;
- assertArithmeticOK(*semantics);
assert(semantics == rhs.semantics);
switch (convolve(category, rhs.category)) {
case convolve(fcInfinity, fcNormal):
case convolve(fcInfinity, fcZero):
case convolve(fcNormal, fcZero):
- if(sign)
+ if (sign)
return cmpLessThan;
else
return cmpGreaterThan;
case convolve(fcNormal, fcInfinity):
case convolve(fcZero, fcInfinity):
case convolve(fcZero, fcNormal):
- if(rhs.sign)
+ if (rhs.sign)
return cmpGreaterThan;
else
return cmpLessThan;
case convolve(fcInfinity, fcInfinity):
- if(sign == rhs.sign)
+ if (sign == rhs.sign)
return cmpEqual;
- else if(sign)
+ else if (sign)
return cmpLessThan;
else
return cmpGreaterThan;
}
/* Two normal numbers. Do they have the same sign? */
- if(sign != rhs.sign) {
- if(sign)
+ if (sign != rhs.sign) {
+ if (sign)
result = cmpLessThan;
else
result = cmpGreaterThan;
/* Compare absolute values; invert result if negative. */
result = compareAbsoluteValue(rhs);
- if(sign) {
- if(result == cmpLessThan)
+ if (sign) {
+ if (result == cmpLessThan)
result = cmpGreaterThan;
- else if(result == cmpGreaterThan)
+ else if (result == cmpGreaterThan)
result = cmpLessThan;
}
}
lostFraction lostFraction;
unsigned int newPartCount, oldPartCount;
opStatus fs;
+ int shift;
+ const fltSemantics &fromSemantics = *semantics;
- assertArithmeticOK(*semantics);
- assertArithmeticOK(toSemantics);
lostFraction = lfExactlyZero;
newPartCount = partCountForBits(toSemantics.precision + 1);
oldPartCount = partCount();
+ shift = toSemantics.precision - fromSemantics.precision;
- /* Handle storage complications. If our new form is wider,
- re-allocate our bit pattern into wider storage. If it is
- narrower, we ignore the excess parts, but if narrowing to a
- single part we need to free the old storage.
- Be careful not to reference significandParts for zeroes
- and infinities, since it aborts. */
+ bool X86SpecialNan = false;
+ if (&fromSemantics == &APFloat::x87DoubleExtended &&
+ &toSemantics != &APFloat::x87DoubleExtended && category == fcNaN &&
+ (!(*significandParts() & 0x8000000000000000ULL) ||
+ !(*significandParts() & 0x4000000000000000ULL))) {
+ // x86 has some unusual NaNs which cannot be represented in any other
+ // format; note them here.
+ X86SpecialNan = true;
+ }
+
+ // If this is a truncation, perform the shift before we narrow the storage.
+ if (shift < 0 && (category==fcNormal || category==fcNaN))
+ lostFraction = shiftRight(significandParts(), oldPartCount, -shift);
+
+ // Fix the storage so it can hold to new value.
if (newPartCount > oldPartCount) {
+ // The new type requires more storage; make it available.
integerPart *newParts;
newParts = new integerPart[newPartCount];
APInt::tcSet(newParts, 0, newPartCount);
APInt::tcAssign(newParts, significandParts(), oldPartCount);
freeSignificand();
significand.parts = newParts;
- } else if (newPartCount < oldPartCount) {
- /* Capture any lost fraction through truncation of parts so we get
- correct rounding whilst normalizing. */
- if (category==fcNormal)
- lostFraction = lostFractionThroughTruncation
- (significandParts(), oldPartCount, toSemantics.precision);
- if (newPartCount == 1) {
- integerPart newPart = 0;
- if (category==fcNormal || category==fcNaN)
- newPart = significandParts()[0];
- freeSignificand();
- significand.part = newPart;
- }
+ } else if (newPartCount == 1 && oldPartCount != 1) {
+ // Switch to built-in storage for a single part.
+ integerPart newPart = 0;
+ if (category==fcNormal || category==fcNaN)
+ newPart = significandParts()[0];
+ freeSignificand();
+ significand.part = newPart;
}
- if(category == fcNormal) {
- /* Re-interpret our bit-pattern. */
- exponent += toSemantics.precision - semantics->precision;
- semantics = &toSemantics;
+ // Now that we have the right storage, switch the semantics.
+ semantics = &toSemantics;
+
+ // If this is an extension, perform the shift now that the storage is
+ // available.
+ if (shift > 0 && (category==fcNormal || category==fcNaN))
+ APInt::tcShiftLeft(significandParts(), newPartCount, shift);
+
+ if (category == fcNormal) {
fs = normalize(rounding_mode, lostFraction);
*losesInfo = (fs != opOK);
} else if (category == fcNaN) {
- int shift = toSemantics.precision - semantics->precision;
- // Do this now so significandParts gets the right answer
- const fltSemantics *oldSemantics = semantics;
- semantics = &toSemantics;
- *losesInfo = false;
- // No normalization here, just truncate
- if (shift>0)
- APInt::tcShiftLeft(significandParts(), newPartCount, shift);
- else if (shift < 0) {
- unsigned ushift = -shift;
- // Figure out if we are losing information. This happens
- // if are shifting out something other than 0s, or if the x87 long
- // double input did not have its integer bit set (pseudo-NaN), or if the
- // x87 long double input did not have its QNan bit set (because the x87
- // hardware sets this bit when converting a lower-precision NaN to
- // x87 long double).
- if (APInt::tcLSB(significandParts(), newPartCount) < ushift)
- *losesInfo = true;
- if (oldSemantics == &APFloat::x87DoubleExtended &&
- (!(*significandParts() & 0x8000000000000000ULL) ||
- !(*significandParts() & 0x4000000000000000ULL)))
- *losesInfo = true;
- APInt::tcShiftRight(significandParts(), newPartCount, ushift);
- }
+ *losesInfo = lostFraction != lfExactlyZero || X86SpecialNan;
// gcc forces the Quiet bit on, which means (float)(double)(float_sNan)
// does not give you back the same bits. This is dubious, and we
// don't currently do it. You're really supposed to get
// an invalid operation signal at runtime, but nobody does that.
fs = opOK;
} else {
- semantics = &toSemantics;
- fs = opOK;
*losesInfo = false;
+ fs = opOK;
}
return fs;
const integerPart *src;
unsigned int dstPartsCount, truncatedBits;
- assertArithmeticOK(*semantics);
-
*isExact = false;
/* Handle the three special cases first. */
- if(category == fcInfinity || category == fcNaN)
+ if (category == fcInfinity || category == fcNaN)
return opInvalidOp;
dstPartsCount = partCountForBits(width);
- if(category == fcZero) {
+ if (category == fcZero) {
APInt::tcSet(parts, 0, dstPartsCount);
// Negative zero can't be represented as an int.
*isExact = !sign;
if (truncatedBits) {
lost_fraction = lostFractionThroughTruncation(src, partCount(),
truncatedBits);
- if (lost_fraction != lfExactlyZero
- && roundAwayFromZero(rounding_mode, lost_fraction, truncatedBits)) {
+ if (lost_fraction != lfExactlyZero &&
+ roundAwayFromZero(rounding_mode, lost_fraction, truncatedBits)) {
if (APInt::tcIncrement(parts, dstPartsCount))
return opInvalidOp; /* Overflow. */
}
{
opStatus fs;
- fs = convertToSignExtendedInteger(parts, width, isSigned, rounding_mode,
+ fs = convertToSignExtendedInteger(parts, width, isSigned, rounding_mode,
isExact);
if (fs == opInvalidOp) {
return fs;
}
+/* Same as convertToInteger(integerPart*, ...), except the result is returned in
+ an APSInt, whose initial bit-width and signed-ness are used to determine the
+ precision of the conversion.
+ */
+APFloat::opStatus
+APFloat::convertToInteger(APSInt &result,
+ roundingMode rounding_mode, bool *isExact) const
+{
+ unsigned bitWidth = result.getBitWidth();
+ SmallVector<uint64_t, 4> parts(result.getNumWords());
+ opStatus status = convertToInteger(
+ parts.data(), bitWidth, result.isSigned(), rounding_mode, isExact);
+ // Keeps the original signed-ness.
+ result = APInt(bitWidth, parts);
+ return status;
+}
+
/* Convert an unsigned integer SRC to a floating point number,
rounding according to ROUNDING_MODE. The sign of the floating
point number is not modified. */
integerPart *dst;
lostFraction lost_fraction;
- assertArithmeticOK(*semantics);
category = fcNormal;
omsb = APInt::tcMSB(src, srcCount) + 1;
dst = significandParts();
dstCount = partCount();
precision = semantics->precision;
- /* We want the most significant PRECISON bits of SRC. There may not
+ /* We want the most significant PRECISION bits of SRC. There may not
be that many; extract what we can. */
if (precision <= omsb) {
exponent = omsb - 1;
{
opStatus status;
- assertArithmeticOK(*semantics);
- if (isSigned
- && APInt::tcExtractBit(src, srcCount * integerPartWidth - 1)) {
+ if (isSigned &&
+ APInt::tcExtractBit(src, srcCount * integerPartWidth - 1)) {
integerPart *copy;
/* If we're signed and negative negate a copy. */
roundingMode rounding_mode)
{
unsigned int partCount = partCountForBits(width);
- APInt api = APInt(width, partCount, parts);
+ APInt api = APInt(width, makeArrayRef(parts, partCount));
sign = false;
- if(isSigned && APInt::tcExtractBit(parts, width - 1)) {
+ if (isSigned && APInt::tcExtractBit(parts, width - 1)) {
sign = true;
api = -api;
}
}
APFloat::opStatus
-APFloat::convertFromHexadecimalString(const StringRef &s,
- roundingMode rounding_mode)
+APFloat::convertFromHexadecimalString(StringRef s, roundingMode rounding_mode)
{
lostFraction lost_fraction = lfExactlyZero;
integerPart *significand;
StringRef::iterator p = skipLeadingZeroesAndAnyDot(begin, end, &dot);
firstSignificantDigit = p;
- for(; p != end;) {
+ for (; p != end;) {
integerPart hex_value;
- if(*p == '.') {
+ if (*p == '.') {
assert(dot == end && "String contains multiple dots");
dot = p++;
if (p == end) {
}
hex_value = hexDigitValue(*p);
- if(hex_value == -1U) {
+ if (hex_value == -1U) {
break;
}
break;
} else {
/* Store the number whilst 4-bit nibbles remain. */
- if(bitPos) {
+ 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)
+ while (p != end && hexDigitValue(*p) != -1U)
p++;
break;
}
assert((dot == end || p - begin != 1) && "Significand has no digits");
/* Ignore the exponent if we are zero. */
- if(p != firstSignificantDigit) {
+ if (p != firstSignificantDigit) {
int expAdjustment;
/* Implicit hexadecimal point? */
/* Calculate the exponent adjustment implicit in the number of
significant digits. */
expAdjustment = static_cast<int>(dot - firstSignificantDigit);
- if(expAdjustment < 0)
+ if (expAdjustment < 0)
expAdjustment++;
expAdjustment = expAdjustment * 4 - 1;
roundingMode rounding_mode)
{
unsigned int parts, pow5PartCount;
- fltSemantics calcSemantics = { 32767, -32767, 0, true };
+ fltSemantics calcSemantics = { 32767, -32767, 0 };
integerPart pow5Parts[maxPowerOfFiveParts];
bool isNearest;
- isNearest = (rounding_mode == rmNearestTiesToEven
- || rounding_mode == rmNearestTiesToAway);
+ isNearest = (rounding_mode == rmNearestTiesToEven ||
+ rounding_mode == rmNearestTiesToAway);
parts = partCountForBits(semantics->precision + 11);
}
APFloat::opStatus
-APFloat::convertFromDecimalString(const StringRef &str, roundingMode rounding_mode)
+APFloat::convertFromDecimalString(StringRef str, roundingMode rounding_mode)
{
decimalInfo D;
opStatus fs;
if (decDigitValue(*D.firstSigDigit) >= 10U) {
category = fcZero;
fs = opOK;
- } else if ((D.normalizedExponent + 1) * 28738
- <= 8651 * (semantics->minExponent - (int) semantics->precision)) {
+
+ /* Check whether the normalized exponent is high enough to overflow
+ max during the log-rebasing in the max-exponent check below. */
+ } else if (D.normalizedExponent - 1 > INT_MAX / 42039) {
+ fs = handleOverflow(rounding_mode);
+
+ /* If it wasn't, then it also wasn't high enough to overflow max
+ during the log-rebasing in the min-exponent check. Check that it
+ won't overflow min in either check, then perform the min-exponent
+ check. */
+ } else if (D.normalizedExponent - 1 < INT_MIN / 42039 ||
+ (D.normalizedExponent + 1) * 28738 <=
+ 8651 * (semantics->minExponent - (int) semantics->precision)) {
/* Underflow to zero and round. */
zeroSignificand();
fs = normalize(rounding_mode, lfLessThanHalf);
+
+ /* We can finally safely perform the max-exponent check. */
} else if ((D.normalizedExponent - 1) * 42039
>= 12655 * semantics->maxExponent) {
/* Overflow and round. */
}
APFloat::opStatus
-APFloat::convertFromString(const StringRef &str, roundingMode rounding_mode)
+APFloat::convertFromString(StringRef str, roundingMode rounding_mode)
{
- assertArithmeticOK(*semantics);
assert(!str.empty() && "Invalid string length");
/* Handle a leading minus sign. */
StringRef::iterator p = str.begin();
size_t slen = str.size();
sign = *p == '-' ? 1 : 0;
- if(*p == '-' || *p == '+') {
+ if (*p == '-' || *p == '+') {
p++;
slen--;
assert(slen && "String has no digits");
}
- if(slen >= 2 && p[0] == '0' && (p[1] == 'x' || p[1] == 'X')) {
+ if (slen >= 2 && p[0] == '0' && (p[1] == 'x' || p[1] == 'X')) {
assert(slen - 2 && "Invalid string");
return convertFromHexadecimalString(StringRef(p + 2, slen - 2),
rounding_mode);
{
char *p;
- assertArithmeticOK(*semantics);
-
p = dst;
if (sign)
*dst++ = '-';
return writeSignedDecimal (dst, exponent);
}
-// For good performance it is desirable for different APFloats
-// to produce different integers.
-uint32_t
-APFloat::getHashValue() const
-{
- if (category==fcZero) return sign<<8 | semantics->precision ;
- else if (category==fcInfinity) return sign<<9 | semantics->precision;
- else if (category==fcNaN) return 1<<10 | semantics->precision;
- else {
- uint32_t hash = sign<<11 | semantics->precision | exponent<<12;
- const integerPart* p = significandParts();
- for (int i=partCount(); i>0; i--, p++)
- hash ^= ((uint32_t)*p) ^ (uint32_t)((*p)>>32);
- return hash;
- }
+hash_code llvm::hash_value(const APFloat &Arg) {
+ if (Arg.category != APFloat::fcNormal)
+ return hash_combine((uint8_t)Arg.category,
+ // NaN has no sign, fix it at zero.
+ Arg.isNaN() ? (uint8_t)0 : (uint8_t)Arg.sign,
+ Arg.semantics->precision);
+
+ // Normal floats need their exponent and significand hashed.
+ return hash_combine((uint8_t)Arg.category, (uint8_t)Arg.sign,
+ Arg.semantics->precision, Arg.exponent,
+ hash_combine_range(
+ Arg.significandParts(),
+ Arg.significandParts() + Arg.partCount()));
}
// Conversion from APFloat to/from host float/double. It may eventually be
words[0] = mysignificand;
words[1] = ((uint64_t)(sign & 1) << 15) |
(myexponent & 0x7fffLL);
- return APInt(80, 2, words);
+ return APInt(80, words);
}
APInt
assert(semantics == (const llvm::fltSemantics*)&PPCDoubleDouble);
assert(partCount()==2);
- uint64_t myexponent, mysignificand, myexponent2, mysignificand2;
-
- if (category==fcNormal) {
- myexponent = exponent + 1023; //bias
- myexponent2 = exponent2 + 1023;
- mysignificand = significandParts()[0];
- mysignificand2 = significandParts()[1];
- if (myexponent==1 && !(mysignificand & 0x10000000000000LL))
- myexponent = 0; // denormal
- if (myexponent2==1 && !(mysignificand2 & 0x10000000000000LL))
- myexponent2 = 0; // denormal
- } else if (category==fcZero) {
- myexponent = 0;
- mysignificand = 0;
- myexponent2 = 0;
- mysignificand2 = 0;
- } else if (category==fcInfinity) {
- myexponent = 0x7ff;
- myexponent2 = 0;
- mysignificand = 0;
- mysignificand2 = 0;
+ uint64_t words[2];
+ opStatus fs;
+ bool losesInfo;
+
+ // Convert number to double. To avoid spurious underflows, we re-
+ // normalize against the "double" minExponent first, and only *then*
+ // truncate the mantissa. The result of that second conversion
+ // may be inexact, but should never underflow.
+ // Declare fltSemantics before APFloat that uses it (and
+ // saves pointer to it) to ensure correct destruction order.
+ fltSemantics extendedSemantics = *semantics;
+ extendedSemantics.minExponent = IEEEdouble.minExponent;
+ APFloat extended(*this);
+ fs = extended.convert(extendedSemantics, rmNearestTiesToEven, &losesInfo);
+ assert(fs == opOK && !losesInfo);
+ (void)fs;
+
+ APFloat u(extended);
+ fs = u.convert(IEEEdouble, rmNearestTiesToEven, &losesInfo);
+ assert(fs == opOK || fs == opInexact);
+ (void)fs;
+ words[0] = *u.convertDoubleAPFloatToAPInt().getRawData();
+
+ // If conversion was exact or resulted in a special case, we're done;
+ // just set the second double to zero. Otherwise, re-convert back to
+ // the extended format and compute the difference. This now should
+ // convert exactly to double.
+ if (u.category == fcNormal && losesInfo) {
+ fs = u.convert(extendedSemantics, rmNearestTiesToEven, &losesInfo);
+ assert(fs == opOK && !losesInfo);
+ (void)fs;
+
+ APFloat v(extended);
+ v.subtract(u, rmNearestTiesToEven);
+ fs = v.convert(IEEEdouble, rmNearestTiesToEven, &losesInfo);
+ assert(fs == opOK && !losesInfo);
+ (void)fs;
+ words[1] = *v.convertDoubleAPFloatToAPInt().getRawData();
} else {
- assert(category == fcNaN && "Unknown category");
- myexponent = 0x7ff;
- mysignificand = significandParts()[0];
- myexponent2 = exponent2;
- mysignificand2 = significandParts()[1];
+ words[1] = 0;
}
- uint64_t words[2];
- words[0] = ((uint64_t)(sign & 1) << 63) |
- ((myexponent & 0x7ff) << 52) |
- (mysignificand & 0xfffffffffffffLL);
- words[1] = ((uint64_t)(sign2 & 1) << 63) |
- ((myexponent2 & 0x7ff) << 52) |
- (mysignificand2 & 0xfffffffffffffLL);
- return APInt(128, 2, words);
+ return APInt(128, words);
}
APInt
((myexponent & 0x7fff) << 48) |
(mysignificand2 & 0xffffffffffffLL);
- return APInt(128, 2, words);
+ return APInt(128, words);
}
APInt
assert(api.getBitWidth()==128);
uint64_t i1 = api.getRawData()[0];
uint64_t i2 = api.getRawData()[1];
- uint64_t myexponent = (i1 >> 52) & 0x7ff;
- uint64_t mysignificand = i1 & 0xfffffffffffffLL;
- uint64_t myexponent2 = (i2 >> 52) & 0x7ff;
- uint64_t mysignificand2 = i2 & 0xfffffffffffffLL;
+ opStatus fs;
+ bool losesInfo;
- initialize(&APFloat::PPCDoubleDouble);
- assert(partCount()==2);
+ // Get the first double and convert to our format.
+ initFromDoubleAPInt(APInt(64, i1));
+ fs = convert(PPCDoubleDouble, rmNearestTiesToEven, &losesInfo);
+ assert(fs == opOK && !losesInfo);
+ (void)fs;
- sign = static_cast<unsigned int>(i1>>63);
- sign2 = static_cast<unsigned int>(i2>>63);
- if (myexponent==0 && mysignificand==0) {
- // exponent, significand meaningless
- // exponent2 and significand2 are required to be 0; we don't check
- category = fcZero;
- } else if (myexponent==0x7ff && mysignificand==0) {
- // exponent, significand meaningless
- // exponent2 and significand2 are required to be 0; we don't check
- category = fcInfinity;
- } else if (myexponent==0x7ff && mysignificand!=0) {
- // exponent meaningless. So is the whole second word, but keep it
- // for determinism.
- category = fcNaN;
- exponent2 = myexponent2;
- significandParts()[0] = mysignificand;
- significandParts()[1] = mysignificand2;
- } else {
- category = fcNormal;
- // Note there is no category2; the second word is treated as if it is
- // fcNormal, although it might be something else considered by itself.
- exponent = myexponent - 1023;
- exponent2 = myexponent2 - 1023;
- significandParts()[0] = mysignificand;
- significandParts()[1] = mysignificand2;
- if (myexponent==0) // denormal
- exponent = -1022;
- else
- significandParts()[0] |= 0x10000000000000LL; // integer bit
- if (myexponent2==0)
- exponent2 = -1022;
- else
- significandParts()[1] |= 0x10000000000000LL; // integer bit
+ // Unless we have a special case, add in second double.
+ if (category == fcNormal) {
+ APFloat v(APInt(64, i2));
+ fs = v.convert(PPCDoubleDouble, rmNearestTiesToEven, &losesInfo);
+ assert(fs == opOK && !losesInfo);
+ (void)fs;
+
+ add(v, rmNearestTiesToEven);
}
}
llvm_unreachable(0);
}
+APFloat
+APFloat::getAllOnesValue(unsigned BitWidth, bool isIEEE)
+{
+ return APFloat(APInt::getAllOnesValue(BitWidth), isIEEE);
+}
+
APFloat APFloat::getLargest(const fltSemantics &Sem, bool Negative) {
APFloat Val(Sem, fcNormal, Negative);
significand[i] = ~((integerPart) 0);
// ...and then clear the top bits for internal consistency.
- significand[N-1]
- &= (((integerPart) 1) << ((Sem.precision % integerPartWidth) - 1)) - 1;
+ if (Sem.precision % integerPartWidth != 0)
+ significand[N-1] &=
+ (((integerPart) 1) << (Sem.precision % integerPartWidth)) - 1;
return Val;
}
Val.exponent = Sem.minExponent;
Val.zeroSignificand();
- Val.significandParts()[partCountForBits(Sem.precision)-1]
- |= (((integerPart) 1) << ((Sem.precision % integerPartWidth) - 1));
+ Val.significandParts()[partCountForBits(Sem.precision)-1] |=
+ (((integerPart) 1) << ((Sem.precision - 1) % integerPartWidth));
return Val;
}
-APFloat::APFloat(const APInt& api, bool isIEEE)
-{
+APFloat::APFloat(const APInt& api, bool isIEEE) {
initFromAPInt(api, isIEEE);
}
-APFloat::APFloat(float f)
-{
- APInt api = APInt(32, 0);
- initFromAPInt(api.floatToBits(f));
+APFloat::APFloat(float f) {
+ initFromAPInt(APInt::floatToBits(f));
}
-APFloat::APFloat(double d)
-{
- APInt api = APInt(64, 0);
- initFromAPInt(api.doubleToBits(d));
+APFloat::APFloat(double d) {
+ initFromAPInt(APInt::doubleToBits(d));
}
namespace {
- static void append(SmallVectorImpl<char> &Buffer,
- unsigned N, const char *Str) {
- unsigned Start = Buffer.size();
- Buffer.set_size(Start + N);
- memcpy(&Buffer[Start], Str, N);
- }
-
- template <unsigned N>
- void append(SmallVectorImpl<char> &Buffer, const char (&Str)[N]) {
- append(Buffer, N, Str);
+ void append(SmallVectorImpl<char> &Buffer, StringRef Str) {
+ Buffer.append(Str.begin(), Str.end());
}
/// Removes data from the given significand until it is no more
// Truncate the significand down to its active bit count, but
// don't try to drop below 32.
- unsigned newPrecision = std::min(32U, significand.getActiveBits());
- significand.trunc(newPrecision);
+ unsigned newPrecision = std::max(32U, significand.getActiveBits());
+ significand = significand.trunc(newPrecision);
}
// Rounding down is just a truncation, except we also want to drop
// trailing zeros from the new result.
if (buffer[FirstSignificant - 1] < '5') {
- while (buffer[FirstSignificant] == '0')
+ while (FirstSignificant < N && buffer[FirstSignificant] == '0')
FirstSignificant++;
exp += FirstSignificant;
void APFloat::toString(SmallVectorImpl<char> &Str,
unsigned FormatPrecision,
- unsigned FormatMaxPadding) {
+ unsigned FormatMaxPadding) const {
switch (category) {
case fcInfinity:
if (isNegative())
// Decompose the number into an APInt and an exponent.
int exp = exponent - ((int) semantics->precision - 1);
APInt significand(semantics->precision,
- partCountForBits(semantics->precision),
- significandParts());
+ makeArrayRef(significandParts(),
+ partCountForBits(semantics->precision)));
+
+ // 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;
+ }
// Ignore trailing binary zeros.
int trailingZeros = significand.countTrailingZeros();
// Nothing to do.
} else if (exp > 0) {
// Just shift left.
- significand.zext(semantics->precision + exp);
+ significand = significand.zext(semantics->precision + exp);
significand <<= exp;
exp = 0;
} else { /* exp < 0 */
// To avoid overflow, we have to operate on numbers large
// enough to store N * 5^e:
// log2(N * 5^e) == log2(N) + e * log2(5)
- // <= semantics->precision + e * 2.5
- // (log_2(5) ~ 2.321928)
- unsigned precision = semantics->precision + 5 * texp / 2;
+ // <= semantics->precision + e * 137 / 59
+ // (log_2(5) ~ 2.321928 < 2.322034 ~ 137/59)
+
+ unsigned precision = semantics->precision + (137 * texp + 136) / 59;
// Multiply significand by 5^e.
// N * 5^0101 == N * 5^(1*1) * 5^(0*2) * 5^(1*4) * 5^(0*8)
- significand.zext(precision);
+ significand = significand.zext(precision);
APInt five_to_the_i(precision, 5);
while (true) {
if (texp & 1) significand *= five_to_the_i;
-
+
texp >>= 1;
if (!texp) break;
five_to_the_i *= five_to_the_i;
unsigned NDigits = buffer.size();
- // Check whether we should a non-scientific format.
+ // Check whether we should use scientific notation.
bool FormatScientific;
if (!FormatMaxPadding)
FormatScientific = true;
else {
- unsigned Padding;
if (exp >= 0) {
- // 765e3 == 765000
- // ^^^
- Padding = (unsigned) exp;
+ // 765e3 --> 765000
+ // ^^^
+ // But we shouldn't make the number look more precise than it is.
+ FormatScientific = ((unsigned) exp > FormatMaxPadding ||
+ NDigits + (unsigned) exp > FormatPrecision);
} else {
- unsigned Margin = (unsigned) -exp;
- if (Margin < NDigits) {
+ // Power of the most significant digit.
+ int MSD = exp + (int) (NDigits - 1);
+ if (MSD >= 0) {
// 765e-2 == 7.65
- Padding = 0;
+ FormatScientific = false;
} else {
// 765e-5 == 0.00765
// ^ ^^
- Padding = Margin + 1 - NDigits;
+ FormatScientific = ((unsigned) -MSD) > FormatMaxPadding;
}
}
-
- FormatScientific = (Padding > FormatMaxPadding ||
- Padding + NDigits > FormatPrecision);
}
// Scientific formatting is pretty straightforward.
for (; I != NDigits; ++I)
Str.push_back(buffer[NDigits-I-1]);
}
+
+bool APFloat::getExactInverse(APFloat *inv) const {
+ // Special floats and denormals have no exact inverse.
+ if (category != fcNormal)
+ return false;
+
+ // Check that the number is a power of two by making sure that only the
+ // integer bit is set in the significand.
+ if (significandLSB() != semantics->precision - 1)
+ return false;
+
+ // Get the inverse.
+ APFloat reciprocal(*semantics, 1ULL);
+ if (reciprocal.divide(*this, rmNearestTiesToEven) != opOK)
+ return false;
+
+ // Avoid multiplication with a denormal, it is not safe on all platforms and
+ // may be slower than a normal division.
+ if (reciprocal.significandMSB() + 1 < reciprocal.semantics->precision)
+ return false;
+
+ assert(reciprocal.category == fcNormal &&
+ reciprocal.significandLSB() == reciprocal.semantics->precision - 1);
+
+ if (inv)
+ *inv = reciprocal;
+
+ return true;
+}