lround.c revision 1ec68d336ba97cd53f46053ac10401d16014d075
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak lround = __lround
/*
* lround(x) rounds its argument to the nearest integer, rounding ties
* away from zero, and converts the result to a 32 bit signed integer.
*
* If x is NaN, infinite, or so large that the nearest integer
* would exceed 32 bits, the invalid operation exception is raised.
*/
#include <sys/isa_defs.h> /* _ILP32 */
#include "libm.h"
#if defined(_ILP32)
long
lround(double x) {
union {
unsigned i[2];
double d;
} xx;
unsigned hx, sx, i;
xx.d = x;
hx = xx.i[HIWORD] & ~0x80000000;
sx = xx.i[HIWORD] & 0x80000000;
if (hx < 0x43300000) { /* |x| < 2^52 */
if (hx < 0x3ff00000) { /* |x| < 1 */
if (hx >= 0x3fe00000)
return (sx ? -1L : 1L);
return (0L);
}
/* round x at the integer bit */
if (hx < 0x41300000) {
i = 1 << (0x412 - (hx >> 20));
xx.i[HIWORD] = (xx.i[HIWORD] + i) & ~(i | (i - 1));
xx.i[LOWORD] = 0;
} else {
i = 1 << (0x432 - (hx >> 20));
xx.i[LOWORD] += i;
if (xx.i[LOWORD] < i)
xx.i[HIWORD]++;
xx.i[LOWORD] &= ~(i | (i - 1));
}
}
/* now x is nan, inf, or integral */
return ((long) xx.d);
}
#else
#error Unsupported architecture
#endif /* defined(_ILP32) */