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Diffstat (limited to 'nuttx/lib/math/lib_expf.c')
-rw-r--r-- | nuttx/lib/math/lib_expf.c | 112 |
1 files changed, 0 insertions, 112 deletions
diff --git a/nuttx/lib/math/lib_expf.c b/nuttx/lib/math/lib_expf.c deleted file mode 100644 index eac4641c6..000000000 --- a/nuttx/lib/math/lib_expf.c +++ /dev/null @@ -1,112 +0,0 @@ -/************************************************************************ - * lib/math/lib_expf.c - * - * This file is a part of NuttX: - * - * Copyright (C) 2012 Gregory Nutt. All rights reserved. - * Ported by: Darcy Gong - * - * It derives from the Rhombs OS math library by Nick Johnson which has - * a compatibile, MIT-style license: - * - * Copyright (C) 2009-2011 Nick Johnson <nickbjohnson4224 at gmail.com> - * - * Permission to use, copy, modify, and distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES - * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR - * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES - * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN - * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF - * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. - * - ************************************************************************/ - -/************************************************************************ - * Included Files - ************************************************************************/ - -#include <sys/types.h> -#include <math.h> - -#include "lib_internal.h" - -/************************************************************************ - * Private Data - ************************************************************************/ - -static float _flt_inv_fact[] = -{ - 1.0 / 1.0, // 1/0! - 1.0 / 1.0, // 1/1! - 1.0 / 2.0, // 1/2! - 1.0 / 6.0, // 1/3! - 1.0 / 24.0, // 1/4! - 1.0 / 120.0, // 1/5! - 1.0 / 720.0, // 1/6! - 1.0 / 5040.0, // 1/7! - 1.0 / 40320.0, // 1/8! - 1.0 / 362880.0, // 1/9! - 1.0 / 3628800.0, // 1/10! -}; - -/************************************************************************ - * Public Functions - ************************************************************************/ - -float expf(float x) -{ - size_t int_part; - bool invert; - float value; - float x0; - size_t i; - - if (x == 0) - { - return 1; - } - else if (x < 0) - { - invert = true; - x = -x; - } - else - { - invert = false; - } - - /* Extract integer component */ - - int_part = (size_t) x; - - /* set x to fractional component */ - - x -= (float)int_part; - - /* Perform Taylor series approximation with eleven terms */ - - value = 0.0; - x0 = 1.0; - for (i = 0; i < 10; i++) - { - value += x0 * _flt_inv_fact[i]; - x0 *= x; - } - - /* Multiply by exp of the integer component */ - - value *= lib_expi(int_part); - - if (invert) - { - return (1.0 / value); - } - else - { - return value; - } -} |