diff options
Diffstat (limited to 'src/runtime/softfloat64_test.go')
| -rw-r--r-- | src/runtime/softfloat64_test.go | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/src/runtime/softfloat64_test.go b/src/runtime/softfloat64_test.go new file mode 100644 index 0000000..7347aff --- /dev/null +++ b/src/runtime/softfloat64_test.go @@ -0,0 +1,198 @@ +// Copyright 2010 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package runtime_test + +import ( + "math" + "math/rand" + . "runtime" + "testing" +) + +// turn uint64 op into float64 op +func fop(f func(x, y uint64) uint64) func(x, y float64) float64 { + return func(x, y float64) float64 { + bx := math.Float64bits(x) + by := math.Float64bits(y) + return math.Float64frombits(f(bx, by)) + } +} + +func add(x, y float64) float64 { return x + y } +func sub(x, y float64) float64 { return x - y } +func mul(x, y float64) float64 { return x * y } +func div(x, y float64) float64 { return x / y } + +func TestFloat64(t *testing.T) { + base := []float64{ + 0, + math.Copysign(0, -1), + -1, + 1, + math.NaN(), + math.Inf(+1), + math.Inf(-1), + 0.1, + 1.5, + 1.9999999999999998, // all 1s mantissa + 1.3333333333333333, // 1.010101010101... + 1.1428571428571428, // 1.001001001001... + 1.112536929253601e-308, // first normal + 2, + 4, + 8, + 16, + 32, + 64, + 128, + 256, + 3, + 12, + 1234, + 123456, + -0.1, + -1.5, + -1.9999999999999998, + -1.3333333333333333, + -1.1428571428571428, + -2, + -3, + 1e-200, + 1e-300, + 1e-310, + 5e-324, + 1e-105, + 1e-305, + 1e+200, + 1e+306, + 1e+307, + 1e+308, + } + all := make([]float64, 200) + copy(all, base) + for i := len(base); i < len(all); i++ { + all[i] = rand.NormFloat64() + } + + test(t, "+", add, fop(Fadd64), all) + test(t, "-", sub, fop(Fsub64), all) + if GOARCH != "386" { // 386 is not precise! + test(t, "*", mul, fop(Fmul64), all) + test(t, "/", div, fop(Fdiv64), all) + } +} + +// 64 -hw-> 32 -hw-> 64 +func trunc32(f float64) float64 { + return float64(float32(f)) +} + +// 64 -sw->32 -hw-> 64 +func to32sw(f float64) float64 { + return float64(math.Float32frombits(F64to32(math.Float64bits(f)))) +} + +// 64 -hw->32 -sw-> 64 +func to64sw(f float64) float64 { + return math.Float64frombits(F32to64(math.Float32bits(float32(f)))) +} + +// float64 -hw-> int64 -hw-> float64 +func hwint64(f float64) float64 { + return float64(int64(f)) +} + +// float64 -hw-> int32 -hw-> float64 +func hwint32(f float64) float64 { + return float64(int32(f)) +} + +// float64 -sw-> int64 -hw-> float64 +func toint64sw(f float64) float64 { + i, ok := F64toint(math.Float64bits(f)) + if !ok { + // There's no right answer for out of range. + // Match the hardware to pass the test. + i = int64(f) + } + return float64(i) +} + +// float64 -hw-> int64 -sw-> float64 +func fromint64sw(f float64) float64 { + return math.Float64frombits(Fintto64(int64(f))) +} + +var nerr int + +func err(t *testing.T, format string, args ...interface{}) { + t.Errorf(format, args...) + + // cut errors off after a while. + // otherwise we spend all our time + // allocating memory to hold the + // formatted output. + if nerr++; nerr >= 10 { + t.Fatal("too many errors") + } +} + +func test(t *testing.T, op string, hw, sw func(float64, float64) float64, all []float64) { + for _, f := range all { + for _, g := range all { + h := hw(f, g) + s := sw(f, g) + if !same(h, s) { + err(t, "%g %s %g = sw %g, hw %g\n", f, op, g, s, h) + } + testu(t, "to32", trunc32, to32sw, h) + testu(t, "to64", trunc32, to64sw, h) + testu(t, "toint64", hwint64, toint64sw, h) + testu(t, "fromint64", hwint64, fromint64sw, h) + testcmp(t, f, h) + testcmp(t, h, f) + testcmp(t, g, h) + testcmp(t, h, g) + } + } +} + +func testu(t *testing.T, op string, hw, sw func(float64) float64, v float64) { + h := hw(v) + s := sw(v) + if !same(h, s) { + err(t, "%s %g = sw %g, hw %g\n", op, v, s, h) + } +} + +func hwcmp(f, g float64) (cmp int, isnan bool) { + switch { + case f < g: + return -1, false + case f > g: + return +1, false + case f == g: + return 0, false + } + return 0, true // must be NaN +} + +func testcmp(t *testing.T, f, g float64) { + hcmp, hisnan := hwcmp(f, g) + scmp, sisnan := Fcmp64(math.Float64bits(f), math.Float64bits(g)) + if int32(hcmp) != scmp || hisnan != sisnan { + err(t, "cmp(%g, %g) = sw %v, %v, hw %v, %v\n", f, g, scmp, sisnan, hcmp, hisnan) + } +} + +func same(f, g float64) bool { + if math.IsNaN(f) && math.IsNaN(g) { + return true + } + if math.Copysign(1, f) != math.Copysign(1, g) { + return false + } + return f == g +} |