xref: /freebsd/lib/msun/src/s_fmaximum_numl.c (revision f6e1f27e9f005447e88a9b37df8a75751b1e0c3a)

/*
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
 * Copyright (c) 2026 Jesús Blázquez <jesuscblazquez@gmail.com>
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <math.h>
#include <stdbool.h>

#include "fpmath.h"

long double
fmaximum_numl(long double x, long double y)
{
	union IEEEl2bits u[2];
	bool nan_x, nan_y;

	u[0].e = x;
	mask_nbit_l(u[0]);
	u[1].e = y;
	mask_nbit_l(u[1]);

	nan_x = isnan(x);
	nan_y = isnan(y);

	if (nan_x || nan_y) {
		/* These ternary conditionals force (x+y), so that sNaN's raise exceptions */
		if (nan_x && nan_y)
			return (x + y);
		if (nan_x)
			return ((x + y) != 0.0 ? y : y);
		return ((x + y) != 0.0 ? x : x);
	}

	/* Handle comparisons of signed zeroes. */
	if (u[0].bits.sign != u[1].bits.sign)
		return (u[0].bits.sign ? y : x);

	return (x > y ? x : y);
}