/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
│vi: set et ft=c ts=8 tw=8 fenc=utf-8                                       :vi│
╚──────────────────────────────────────────────────────────────────────────────╝
│                                                                              │
│  Musl Libc                                                                   │
│  Copyright © 2005-2014 Rich Felker, et al.                                   │
│                                                                              │
│  Permission is hereby granted, free of charge, to any person obtaining       │
│  a copy of this software and associated documentation files (the             │
│  "Software"), to deal in the Software without restriction, including         │
│  without limitation the rights to use, copy, modify, merge, publish,         │
│  distribute, sublicense, and/or sell copies of the Software, and to          │
│  permit persons to whom the Software is furnished to do so, subject to       │
│  the following conditions:                                                   │
│                                                                              │
│  The above copyright notice and this permission notice shall be              │
│  included in all copies or substantial portions of the Software.             │
│                                                                              │
│  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             │
│  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          │
│  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      │
│  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        │
│  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        │
│  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           │
│  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      │
│                                                                              │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/math.h"

asm(".ident\t\"\\n\\n\
Musl libc (MIT License)\\n\
Copyright 2005-2014 Rich Felker, et. al.\"");
asm(".include \"libc/disclaimer.inc\"");
// clang-format off

/**
 * Returns fractional part of 𝑥.
 */
double modf(double x, double *iptr)
{
	union {double f; uint64_t i;} u = {x};
	uint64_t mask;
	int e = (int)(u.i>>52 & 0x7ff) - 0x3ff;

	/* no fractional part */
	if (e >= 52) {
		*iptr = x;
		if (e == 0x400 && u.i<<12 != 0) /* nan */
			return x;
		u.i &= 1ULL<<63;
		return u.f;
	}

	/* no integral part*/
	if (e < 0) {
		u.i &= 1ULL<<63;
		*iptr = u.f;
		return x;
	}

	mask = -1ULL>>12>>e;
	if ((u.i & mask) == 0) {
		*iptr = x;
		u.i &= 1ULL<<63;
		return u.f;
	}
	u.i &= ~mask;
	*iptr = u.f;
	return x - u.f;
}

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
__weak_reference(modf, modfl);
#endif