// 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 subtractation 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;
}
EXPECT_FALSE(APFloat(1.40129846e-45f).getExactInverse(0));
}
+TEST(APFloatTest, roundToIntegral) {
+ APFloat T(-0.5), S(3.14), P(0.0);
+
+ P = T;
+ P.roundToIntegral(APFloat::rmTowardZero);
+ EXPECT_EQ(-0.0, P.convertToDouble());
+ P = T;
+ P.roundToIntegral(APFloat::rmTowardNegative);
+ EXPECT_EQ(-1.0, P.convertToDouble());
+ P = T;
+ P.roundToIntegral(APFloat::rmTowardPositive);
+ EXPECT_EQ(-0.0, P.convertToDouble());
+ P = T;
+ P.roundToIntegral(APFloat::rmNearestTiesToEven);
+ EXPECT_EQ(-0.0, P.convertToDouble());
+
+ P = S;
+ P.roundToIntegral(APFloat::rmTowardZero);
+ EXPECT_EQ(3.0, P.convertToDouble());
+ P = S;
+ P.roundToIntegral(APFloat::rmTowardNegative);
+ EXPECT_EQ(3.0, P.convertToDouble());
+ P = S;
+ P.roundToIntegral(APFloat::rmTowardPositive);
+ EXPECT_EQ(4.0, P.convertToDouble());
+ P = S;
+ P.roundToIntegral(APFloat::rmNearestTiesToEven);
+ EXPECT_EQ(3.0, P.convertToDouble());
+}
+
TEST(APFloatTest, getLargest) {
EXPECT_EQ(3.402823466e+38f, APFloat::getLargest(APFloat::IEEEsingle).convertToFloat());
EXPECT_EQ(1.7976931348623158e+308, APFloat::getLargest(APFloat::IEEEdouble).convertToDouble());