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// Copyright 2009 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 math
/*
* this table might overflow 127-bit exponent representations.
* in that case, truncate it after 1.0e38.
* it is important to get all one can from this
* routine since it is used in atof to scale numbers.
* the presumption is that GO converts fp numbers better
* than multipication of lower powers of 10.
*/
const tabsize = 70;
var tab[tabsize] float64;
export func Pow10(e int) float64 {
if e < 0 {
return 1/Pow10(-e);
}
if e < tabsize {
return tab[e];
}
m := e/2;
return Pow10(m) * Pow10(e-m);
}
func init() {
tab[0] = 1.0e0;
tab[1] = 1.0e1;
for i:=2; i<tabsize; i++ {
m := i/2;
tab[i] = tab[m] * tab[i-m];
}
}
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