llrintf.c revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af
/*
* 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 __llrintf = llrintf
#if defined(__sparcv9) || defined(__amd64)
#pragma weak lrintf = llrintf
#pragma weak __lrintf = llrintf
#endif
#include "libm.h"
long long
llrintf(float x) {
/*
* Note: The following code works on x86 (in the default rounding
* precision mode), but one should just use the fistpll instruction
* instead.
*/
union {
unsigned i;
float f;
} xx, yy;
unsigned hx;
xx.f = x;
hx = xx.i & ~0x80000000;
if (hx < 0x4b000000) { /* |x| < 2^23 */
/* add and subtract a power of two to round x to an integer */
#if defined(__sparc) || defined(__amd64)
yy.i = (xx.i & 0x80000000) | 0x4b000000;
#elif defined(__i386)
/* assume 64-bit precision */
yy.i = (xx.i & 0x80000000) | 0x5f000000;
#else
#error Unknown architecture
#endif
x = (x + yy.f) - yy.f;
/*
* on LP32 architectures, we can just convert x to a 32-bit
* integer and sign-extend it
*/
return ((long) x);
}
/* now x is nan, inf, or integral */
return ((long long) x);
}