diff options
Diffstat (limited to 'libgo/go/math/big/float_test.go')
| -rw-r--r-- | libgo/go/math/big/float_test.go | 39 |
1 files changed, 32 insertions, 7 deletions
diff --git a/libgo/go/math/big/float_test.go b/libgo/go/math/big/float_test.go index 5fd49bb8946..7d6bf034dff 100644 --- a/libgo/go/math/big/float_test.go +++ b/libgo/go/math/big/float_test.go @@ -1007,9 +1007,9 @@ func TestFloatFloat64(t *testing.T) { {"0x.fffffffffffffp-1022", smallestNormalFloat64 - math.SmallestNonzeroFloat64, Exact}, {"4503599627370495p-1074", smallestNormalFloat64 - math.SmallestNonzeroFloat64, Exact}, - // http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/ + // https://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/ {"2.2250738585072011e-308", 2.225073858507201e-308, Below}, - // http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/ + // https://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/ {"2.2250738585072012e-308", 2.2250738585072014e-308, Above}, } { for i := 0; i < 2; i++ { @@ -1258,6 +1258,31 @@ func TestFloatAdd(t *testing.T) { } } +// TestFloatAddRoundZero tests Float.Add/Sub rounding when the result is exactly zero. +// x + (-x) or x - x for non-zero x should be +0 in all cases except when +// the rounding mode is ToNegativeInf in which case it should be -0. +func TestFloatAddRoundZero(t *testing.T) { + for _, mode := range [...]RoundingMode{ToNearestEven, ToNearestAway, ToZero, AwayFromZero, ToPositiveInf, ToNegativeInf} { + x := NewFloat(5.0) + y := new(Float).Neg(x) + want := NewFloat(0.0) + if mode == ToNegativeInf { + want.Neg(want) + } + got := new(Float).SetMode(mode) + got.Add(x, y) + if got.Cmp(want) != 0 || got.neg != (mode == ToNegativeInf) { + t.Errorf("%s:\n\t %v\n\t+ %v\n\t= %v\n\twant %v", + mode, x, y, got, want) + } + got.Sub(x, x) + if got.Cmp(want) != 0 || got.neg != (mode == ToNegativeInf) { + t.Errorf("%v:\n\t %v\n\t- %v\n\t= %v\n\twant %v", + mode, x, x, got, want) + } + } +} + // TestFloatAdd32 tests that Float.Add/Sub of numbers with // 24bit mantissa behaves like float32 addition/subtraction // (excluding denormal numbers). @@ -1372,7 +1397,7 @@ func TestFloatMul(t *testing.T) { got.Mul(x, y) want := zbits.round(prec, mode) if got.Cmp(want) != 0 { - t.Errorf("i = %d, prec = %d, %s:\n\t %s %v\n\t* %s %v\n\t= %s\n\twant %s", + t.Errorf("i = %d, prec = %d, %s:\n\t %v %v\n\t* %v %v\n\t= %v\n\twant %v", i, prec, mode, x, xbits, y, ybits, got, want) } @@ -1382,7 +1407,7 @@ func TestFloatMul(t *testing.T) { got.Quo(z, x) want = ybits.round(prec, mode) if got.Cmp(want) != 0 { - t.Errorf("i = %d, prec = %d, %s:\n\t %s %v\n\t/ %s %v\n\t= %s\n\twant %s", + t.Errorf("i = %d, prec = %d, %s:\n\t %v %v\n\t/ %v %v\n\t= %v\n\twant %v", i, prec, mode, z, zbits, x, xbits, got, want) } } @@ -1465,13 +1490,13 @@ func TestIssue6866(t *testing.T) { z2.Sub(two, p) if z1.Cmp(z2) != 0 { - t.Fatalf("prec %d: got z1 = %s != z2 = %s; want z1 == z2\n", prec, z1, z2) + t.Fatalf("prec %d: got z1 = %v != z2 = %v; want z1 == z2\n", prec, z1, z2) } if z1.Sign() != 0 { - t.Errorf("prec %d: got z1 = %s; want 0", prec, z1) + t.Errorf("prec %d: got z1 = %v; want 0", prec, z1) } if z2.Sign() != 0 { - t.Errorf("prec %d: got z2 = %s; want 0", prec, z2) + t.Errorf("prec %d: got z2 = %v; want 0", prec, z2) } } } |