/**************************************************************************** * libs/libc/math/lib_rintl.c * * Copyright (C) 2007, 2011, 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Type Declarations ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /**************************************************************************** * Public Constant Data ****************************************************************************/ /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Constant Data ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ long double rintl(long double x) { int64_t llinteger; long double fremainder; long double ret; /* If the current rounding mode rounds toward negative * infinity, rint() is identical to floor(). If the current * rounding mode rounds toward positive infinity, rint() is * identical to ceil(). */ #if defined(CONFIG_FP_ROUND_POSITIVE) && CONFIG_FP_ROUNDING_POSITIVE != 0 ret = ceil(x); #elif defined(CONFIG_FP_ROUND_NEGATIVE) && CONFIG_FP_ROUNDING_NEGATIVE != 0 ret = floor(x); #else /* In the default rounding mode (round to nearest), rint(x) is the * integer nearest x with the additional stipulation that if * |rint(x)-x|=1/2, then rint(x) is even. */ llinteger = (int64_t)x; fremainder = x - (long double)llinteger; if (x < 0.0) { /* fremainder should be in range 0 .. -1 */ if (fremainder == -0.5) { llinteger = ((llinteger + 1) & ~1); } else if (fremainder < -0.5) { llinteger--; } } else { /* fremainder should be in range 0 .. 1 */ if (fremainder == 0.5) { llinteger = ((llinteger + 1) & ~1); } else if (fremainder > 0.5) { llinteger++; } } ret = (long double)llinteger; #endif return ret; }