From 73df946d56c74384511a194dd01dbe099584fd1a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 15:14:23 +0200 Subject: Adding upstream version 1.16.10. Signed-off-by: Daniel Baumann --- src/math/pow10.go | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 src/math/pow10.go (limited to 'src/math/pow10.go') diff --git a/src/math/pow10.go b/src/math/pow10.go new file mode 100644 index 0000000..1234e20 --- /dev/null +++ b/src/math/pow10.go @@ -0,0 +1,46 @@ +// 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 + +// pow10tab stores the pre-computed values 10**i for i < 32. +var pow10tab = [...]float64{ + 1e00, 1e01, 1e02, 1e03, 1e04, 1e05, 1e06, 1e07, 1e08, 1e09, + 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, + 1e20, 1e21, 1e22, 1e23, 1e24, 1e25, 1e26, 1e27, 1e28, 1e29, + 1e30, 1e31, +} + +// pow10postab32 stores the pre-computed value for 10**(i*32) at index i. +var pow10postab32 = [...]float64{ + 1e00, 1e32, 1e64, 1e96, 1e128, 1e160, 1e192, 1e224, 1e256, 1e288, +} + +// pow10negtab32 stores the pre-computed value for 10**(-i*32) at index i. +var pow10negtab32 = [...]float64{ + 1e-00, 1e-32, 1e-64, 1e-96, 1e-128, 1e-160, 1e-192, 1e-224, 1e-256, 1e-288, 1e-320, +} + +// Pow10 returns 10**n, the base-10 exponential of n. +// +// Special cases are: +// Pow10(n) = 0 for n < -323 +// Pow10(n) = +Inf for n > 308 +func Pow10(n int) float64 { + if 0 <= n && n <= 308 { + return pow10postab32[uint(n)/32] * pow10tab[uint(n)%32] + } + + if -323 <= n && n <= 0 { + return pow10negtab32[uint(-n)/32] / pow10tab[uint(-n)%32] + } + + // n < -323 || 308 < n + if n > 0 { + return Inf(1) + } + + // n < -323 + return 0 +} -- cgit v1.2.3