213b954a90
- Add check in roundx() functions for infinite or NaN cases - Add block to avoid style warnings - Define long double constants and macros for infinity and nan - Correct return syntax to match NuttX style - Make c89 compliant - Fix definitions of INFINITY_L/NAN_L * include/nuttx/lib/math.h - match standard naming conventions - Rename isinf_l to isinfl - Rename isinf_f to isinff - Add finite() - Add finitel() - Add finitef() - Define isnanl and isnanf - Define isfinite() so that it uses the appropriate macro * libs/libc/math/lib_asinf.c libs/libc/math/lib_asinl.c libs/libc/math/lib_roundf.c libs/libc/math/lib_roundl.c libs/libc/math/lib_sqrtf.c libs/libc/math/lib_sqrtl.c - Use renamed macros - Use correct NAN_x or INFINIT_x macro on returns
92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
/****************************************************************************
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* libs/libc/math/lib_logl.c
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*
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* This file is a part of NuttX:
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*
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* Copyright (C) 2012, 2017 Gregory Nutt. All rights reserved.
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* Ported by: Darcy Gong
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*
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* It derives from the Rhombus OS math library by Nick Johnson which has
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* a compatible, MIT-style license:
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*
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* Copyright (C) 2009, 2010 Nick Johnson <nickbjohnson4224 at gmail.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/compiler.h>
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#include <math.h>
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#include <float.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define LDBL_MAX_EXP_X 700.0
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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#ifdef CONFIG_HAVE_LONG_DOUBLE
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long double logl(long double x)
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{
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long double y;
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long double y_old;
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long double ey;
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long double epsilon;
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y = 0.0;
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y_old = 1.0;
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epsilon = LDBL_EPSILON;
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while (y > y_old + epsilon || y < y_old - epsilon)
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{
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y_old = y;
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ey = expl(y);
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y -= (ey - x) / ey;
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if (y > LDBL_MAX_EXP_X)
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{
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y = LDBL_MAX_EXP_X;
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}
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if (y < -LDBL_MAX_EXP_X)
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{
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y = -LDBL_MAX_EXP_X;
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}
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epsilon = (fabsl(y) > 1.0) ? fabsl(y) * LDBL_EPSILON : LDBL_EPSILON;
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}
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if (y == LDBL_MAX_EXP_X)
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{
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return INFINITY_L;
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}
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if (y == -LDBL_MAX_EXP_X)
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{
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return INFINITY_L;
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}
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return y;
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}
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#endif
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