mirror of
https://github.com/golang/go
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72 lines
1.9 KiB
Go
72 lines
1.9 KiB
Go
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// run
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// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This test checks if the compiler's internal constant
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// arithmetic correctly rounds up floating-point values
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// that become the smallest denormal value.
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//
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// See also related issue 14553 and test issue14553.go.
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package main
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import (
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"fmt"
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"math"
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)
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const (
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p149 = 1.0 / (1 << 149) // 1p-149
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p500 = 1.0 / (1 << 500) // 1p-500
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p1074 = p500 * p500 / (1<<74) // 1p-1074
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)
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const (
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m0000p149 = 0x0 / 16.0 * p149 // = 0.0000p-149
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m1000p149 = 0x8 / 16.0 * p149 // = 0.1000p-149
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m1001p149 = 0x9 / 16.0 * p149 // = 0.1001p-149
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m1011p149 = 0xb / 16.0 * p149 // = 0.1011p-149
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m1100p149 = 0xc / 16.0 * p149 // = 0.1100p-149
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m0000p1074 = 0x0 / 16.0 * p1074 // = 0.0000p-1074
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m1000p1074 = 0x8 / 16.0 * p1074 // = 0.1000p-1074
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m1001p1074 = 0x9 / 16.0 * p1074 // = 0.1001p-1074
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m1011p1074 = 0xb / 16.0 * p1074 // = 0.1011p-1074
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m1100p1074 = 0xc / 16.0 * p1074 // = 0.1100p-1074
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)
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func main() {
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test32(float32(m0000p149), f32(m0000p149))
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test32(float32(m1000p149), f32(m1000p149))
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test32(float32(m1001p149), f32(m1001p149))
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test32(float32(m1011p149), f32(m1011p149))
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test32(float32(m1100p149), f32(m1100p149))
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test64(float64(m0000p1074), f64(m0000p1074))
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test64(float64(m1000p1074), f64(m1000p1074))
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test64(float64(m1001p1074), f64(m1001p1074))
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test64(float64(m1011p1074), f64(m1011p1074))
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test64(float64(m1100p1074), f64(m1100p1074))
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}
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func f32(x float64) float32 { return float32(x) }
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func f64(x float64) float64 { return float64(x) }
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func test32(a, b float32) {
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abits := math.Float32bits(a)
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bbits := math.Float32bits(b)
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if abits != bbits {
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panic(fmt.Sprintf("%08x != %08x\n", abits, bbits))
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}
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}
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func test64(a, b float64) {
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abits := math.Float64bits(a)
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bbits := math.Float64bits(b)
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if abits != bbits {
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panic(fmt.Sprintf("%016x != %016x\n", abits, bbits))
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}
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}
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