1 /* 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG> 5 * Copyright (c) 2026 Jesús Blázquez <jesuscblazquez@gmail.com> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <float.h> 31 #include <math.h> 32 #include <stdbool.h> 33 34 #include "fpmath.h" 35 36 #ifdef USE_BUILTIN_FMAXIMUM_NUM 37 double 38 fmaximum_num(double x, double y) 39 { 40 return (__builtin_fmaximum_num(x, y)); 41 } 42 #else 43 double 44 fmaximum_num(double x, double y) 45 { 46 union IEEEd2bits u[2]; 47 bool nan_x, nan_y; 48 49 u[0].d = x; 50 u[1].d = y; 51 52 nan_x = isnan(x); 53 nan_y = isnan(y); 54 55 if (nan_x || nan_y) { 56 /* If both are NaN, adding returns qNaN */ 57 if (nan_x && nan_y) 58 return (x + y); 59 60 /* force_except makes sure sNaN's raise exceptions */ 61 volatile double force_except = x + y; 62 force_except; 63 64 if (nan_x) 65 return (y); 66 else 67 return (x); 68 } 69 70 /* Handle comparisons of signed zeroes. */ 71 if (u[0].bits.sign != u[1].bits.sign) 72 return (u[u[0].bits.sign].d); 73 74 return (x > y ? x : y); 75 } 76 #endif 77 78 #if (LDBL_MANT_DIG == 53) 79 __weak_reference(fmaximum_num, fmaximum_numl); 80 #endif 81