/* Assumed in hexadecimal significand parsing, and conversion to
hexadecimal strings. */
-#define COMPILE_TIME_ASSERT(cond) extern int CTAssert[(cond) ? 1 : -1]
-COMPILE_TIME_ASSERT(integerPartWidth % 4 == 0);
+static_assert(integerPartWidth % 4 == 0, "Part width must be divisible by 4!");
namespace llvm {
/* Number of bits in the significand. This includes the integer
bit. */
unsigned int precision;
+
+ /* Number of bits actually used in the semantics. */
+ unsigned int sizeInBits;
};
- 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 };
+ const fltSemantics APFloat::IEEEhalf = { 15, -14, 11, 16 };
+ const fltSemantics APFloat::IEEEsingle = { 127, -126, 24, 32 };
+ const fltSemantics APFloat::IEEEdouble = { 1023, -1022, 53, 64 };
+ const fltSemantics APFloat::IEEEquad = { 16383, -16382, 113, 128 };
+ const fltSemantics APFloat::x87DoubleExtended = { 16383, -16382, 64, 80 };
+ const fltSemantics APFloat::Bogus = { 0, 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
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 };
+ const fltSemantics APFloat::PPCDoubleDouble = { 1023, -1022 + 53, 53 + 53, 128 };
/* A tight upper bound on number of parts required to hold the value
pow(5, power) is
{
StringRef::iterator p = begin;
*dot = end;
- while (*p == '0' && p != end)
+ while (p != end && *p == '0')
p++;
- if (*p == '.') {
+ if (p != end && *p == '.') {
*dot = p++;
assert(end - begin != 1 && "Significand has no digits");
- while (*p == '0' && p != end)
+ while (p != end && *p == '0')
p++;
}
return false;
if (category==fcZero || category==fcInfinity)
return true;
- else if (isFiniteNonZero() && exponent!=rhs.exponent)
+
+ if (isFiniteNonZero() && exponent != rhs.exponent)
return false;
- else {
- int i= partCount();
- const integerPart* p=significandParts();
- const integerPart* q=rhs.significandParts();
- for (; i>0; i--, p++, q++) {
- if (*p != *q)
- return false;
- }
- return true;
- }
+
+ return std::equal(significandParts(), significandParts() + partCount(),
+ rhs.significandParts());
}
APFloat::APFloat(const fltSemantics &ourSemantics, integerPart value) {
{
return semantics.precision;
}
+APFloat::ExponentType
+APFloat::semanticsMaxExponent(const fltSemantics &semantics)
+{
+ return semantics.maxExponent;
+}
+APFloat::ExponentType
+APFloat::semanticsMinExponent(const fltSemantics &semantics)
+{
+ return semantics.minExponent;
+}
+unsigned int
+APFloat::semanticsSizeInBits(const fltSemantics &semantics)
+{
+ return semantics.sizeInBits;
+}
const integerPart *
APFloat::significandParts() const
assert(semantics == rhs.semantics);
precision = semantics->precision;
- newPartsCount = partCountForBits(precision * 2);
+
+ // Allocate space for twice as many bits as the original significand, plus one
+ // extra bit for the addition to overflow into.
+ newPartsCount = partCountForBits(precision * 2 + 1);
if (newPartsCount > 4)
fullSignificand = new integerPart[newPartsCount];
// *this = a23 . a22 ... a0 * 2^e1
// rhs = b23 . b22 ... b0 * 2^e2
// the result of multiplication is:
- // *this = c47 c46 . c45 ... c0 * 2^(e1+e2)
- // Note that there are two significant bits at the left-hand side of the
- // radix point. Move the radix point toward left by one bit, and adjust
- // exponent accordingly.
- exponent += 1;
-
- if (addend) {
+ // *this = c48 c47 c46 . c45 ... c0 * 2^(e1+e2)
+ // Note that there are three significant bits at the left-hand side of the
+ // radix point: two for the multiplication, and an overflow bit for the
+ // addition (that will always be zero at this point). Move the radix point
+ // toward left by two bits, and adjust exponent accordingly.
+ exponent += 2;
+
+ if (addend && addend->isNonZero()) {
// The intermediate result of the multiplication has "2 * precision"
// signicant bit; adjust the addend to be consistent with mul result.
//
opStatus status;
unsigned int extendedPrecision;
- /* Normalize our MSB. */
- extendedPrecision = 2 * precision;
- if (omsb != extendedPrecision) {
+ // Normalize our MSB to one below the top bit to allow for overflow.
+ extendedPrecision = 2 * precision + 1;
+ if (omsb != extendedPrecision - 1) {
assert(extendedPrecision > omsb);
APInt::tcShiftLeft(fullSignificand, newPartsCount,
- extendedPrecision - omsb);
- exponent -= extendedPrecision - omsb;
+ (extendedPrecision - 1) - omsb);
+ exponent -= (extendedPrecision - 1) - omsb;
}
/* Create new semantics. */
status = extendedAddend.convert(extendedSemantics, rmTowardZero, &ignored);
assert(status == opOK);
(void)status;
+
+ // Shift the significand of the addend right by one bit. This guarantees
+ // that the high bit of the significand is zero (same as fullSignificand),
+ // so the addition will overflow (if it does overflow at all) into the top bit.
+ lost_fraction = extendedAddend.shiftSignificandRight(1);
+ assert(lost_fraction == lfExactlyZero &&
+ "Lost precision while shifting addend for fused-multiply-add.");
+
lost_fraction = addOrSubtractSignificand(extendedAddend, false);
/* Restore our state. */
// having "precision" significant-bits. First, move the radix point from
// poision "2*precision - 1" to "precision - 1". The exponent need to be
// adjusted by "2*precision - 1" - "precision - 1" = "precision".
- exponent -= precision;
+ exponent -= precision + 1;
// In case MSB resides at the left-hand side of radix point, shift the
// mantissa right by some amount to make sure the MSB reside right before
return false;
case rmTowardPositive:
- return sign == false;
+ return !sign;
case rmTowardNegative:
- return sign == true;
+ return sign;
}
llvm_unreachable("Invalid rounding mode found");
}
{
switch (PackCategoriesIntoKey(category, rhs.category)) {
default:
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
case PackCategoriesIntoKey(fcNaN, fcZero):
case PackCategoriesIntoKey(fcNaN, fcNormal):
case PackCategoriesIntoKey(fcZero, fcNaN):
case PackCategoriesIntoKey(fcNormal, fcNaN):
case PackCategoriesIntoKey(fcInfinity, fcNaN):
- sign = false;
+ // We need to be sure to flip the sign here for subtraction because we
+ // don't have a separate negate operation so -NaN becomes 0 - NaN here.
+ sign = rhs.sign ^ subtract;
category = fcNaN;
copySignificand(rhs);
return opOK;
/* Determine if the operation on the absolute values is effectively
an addition or subtraction. */
- subtract ^= (sign ^ rhs.sign) ? true : false;
+ subtract ^= static_cast<bool>(sign ^ rhs.sign);
/* Are we bigger exponent-wise than the RHS? */
bits = exponent - rhs.exponent;
{
switch (PackCategoriesIntoKey(category, rhs.category)) {
default:
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
case PackCategoriesIntoKey(fcNaN, fcZero):
case PackCategoriesIntoKey(fcNaN, fcNormal):
{
switch (PackCategoriesIntoKey(category, rhs.category)) {
default:
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
case PackCategoriesIntoKey(fcZero, fcNaN):
case PackCategoriesIntoKey(fcNormal, fcNaN):
{
switch (PackCategoriesIntoKey(category, rhs.category)) {
default:
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
case PackCategoriesIntoKey(fcNaN, fcZero):
case PackCategoriesIntoKey(fcNaN, fcNormal):
/* Normalized llvm frem (C fmod).
This is not currently correct in all cases. */
APFloat::opStatus
-APFloat::mod(const APFloat &rhs, roundingMode rounding_mode)
+APFloat::mod(const APFloat &rhs)
{
opStatus fs;
fs = modSpecials(rhs);
rmNearestTiesToEven);
assert(fs==opOK); // should always work
- fs = V.multiply(rhs, rounding_mode);
+ fs = V.multiply(rhs, rmNearestTiesToEven);
assert(fs==opOK || fs==opInexact); // should not overflow or underflow
- fs = subtract(V, rounding_mode);
+ fs = subtract(V, rmNearestTiesToEven);
assert(fs==opOK || fs==opInexact); // likewise
if (isZero())
extended-precision calculation. */
if (isFiniteNonZero() &&
multiplicand.isFiniteNonZero() &&
- addend.isFiniteNonZero()) {
+ addend.isFinite()) {
lostFraction lost_fraction;
lost_fraction = multiplySignificand(multiplicand, &addend);
/* 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 && !(fs & opUnderflow) && sign != addend.sign)
sign = (rounding_mode == rmTowardNegative);
} else {
fs = multiplySpecials(multiplicand);
switch (PackCategoriesIntoKey(category, rhs.category)) {
default:
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
case PackCategoriesIntoKey(fcNaN, fcZero):
case PackCategoriesIntoKey(fcNaN, fcNormal):
roundingMode rounding_mode)
{
unsigned int parts, pow5PartCount;
- fltSemantics calcSemantics = { 32767, -32767, 0 };
+ fltSemantics calcSemantics = { 32767, -32767, 0, 0 };
integerPart pow5Parts[maxPowerOfFiveParts];
bool isNearest;
if (Sem == &PPCDoubleDouble)
return initFromPPCDoubleDoubleAPInt(api);
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
}
APFloat
}
}
+unsigned APFloat::getSizeInBits(const fltSemantics &Sem) {
+ return Sem.sizeInBits;
+}
+
/// Make this number the largest magnitude normal number in the given
/// semantics.
void APFloat::makeLargest(bool Negative) {
// internal consistency.
const unsigned NumUnusedHighBits =
PartCount*integerPartWidth - semantics->precision;
- significand[PartCount - 1] = ~integerPart(0) >> NumUnusedHighBits;
+ significand[PartCount - 1] = (NumUnusedHighBits < integerPartWidth)
+ ? (~integerPart(0) >> NumUnusedHighBits)
+ : 0;
}
/// Make this number the smallest magnitude denormal number in the given
exponent = semantics->minExponent-1;
APInt::tcSet(significandParts(), 0, partCount());
}
+
+APFloat llvm::scalbn(APFloat X, int Exp) {
+ if (X.isInfinity() || X.isZero() || X.isNaN())
+ return X;
+
+ auto MaxExp = X.getSemantics().maxExponent;
+ auto MinExp = X.getSemantics().minExponent;
+ if (Exp > (MaxExp - X.exponent))
+ // Overflow saturates to infinity.
+ return APFloat::getInf(X.getSemantics(), X.isNegative());
+ if (Exp < (MinExp - X.exponent))
+ // Underflow saturates to zero.
+ return APFloat::getZero(X.getSemantics(), X.isNegative());
+
+ X.exponent += Exp;
+ return X;
+}
projects / oota-llvm.git / blobdiff