/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
│ vi: set noet ft=c ts=8 sw=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"
__static_yoink("musl_libc_notice");

// clang-format off

/**
 * Returns 𝑥 × 2ʸ.
 */
double scalbn(double x, int n)
{
	union {double f; uint64_t i;} u;
	double_t y = x;

	if (n > 1023) {
		y *= 0x1p1023;
		n -= 1023;
		if (n > 1023) {
			y *= 0x1p1023;
			n -= 1023;
			if (n > 1023)
				n = 1023;
		}
	} else if (n < -1022) {
		/* make sure final n < -53 to avoid double
		   rounding in the subnormal range */
		y *= 0x1p-1022 * 0x1p53;
		n += 1022 - 53;
		if (n < -1022) {
			y *= 0x1p-1022 * 0x1p53;
			n += 1022 - 53;
			if (n < -1022)
				n = -1022;
		}
	}
	u.i = (uint64_t)(0x3ff+n)<<52;
	x = y * u.f;
	return x;
}

__strong_reference(scalbn, ldexp);
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
__weak_reference(scalbn, ldexpl);
__weak_reference(scalbn, scalbnl);
#endif
