29 lines
658 B
Go
29 lines
658 B
Go
// Copyright 2009 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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package math
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func libc_sqrt(float64) float64 __asm__("sqrt")
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// Sqrt returns the square root of x.
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//
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// Special cases are:
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// Sqrt(+Inf) = +Inf
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// Sqrt(±0) = ±0
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// Sqrt(x < 0) = NaN
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// Sqrt(NaN) = NaN
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func Sqrt(x float64) float64 {
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// special cases
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// TODO(rsc): Remove manual inlining of IsNaN, IsInf
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// when compiler does it for us
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switch {
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case x == 0 || x != x || x > MaxFloat64: // x == 0 || IsNaN(x) || IsInf(x, 1):
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return x
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case x < 0:
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return NaN()
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}
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return libc_sqrt(x)
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}
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