1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29 
  30 #if defined(ELFOBJ)
  31 #pragma weak llrintf = __llrintf
  32 #if defined(__sparcv9) || defined(__amd64)
  33 #pragma weak lrintf = __llrintf
  34 #pragma weak __lrintf = __llrintf
  35 #endif
  36 #endif
  37 
  38 #include "libm.h"
  39 
  40 long long
  41 llrintf(float x) {
  42         /*
  43          * Note: The following code works on x86 (in the default rounding
  44          * precision mode), but one should just use the fistpll instruction
  45          * instead.
  46          */
  47         union {
  48                 unsigned i;
  49                 float f;
  50         } xx, yy;
  51         unsigned hx;
  52 
  53         xx.f = x;
  54         hx = xx.i & ~0x80000000;
  55 
  56         if (hx < 0x4b000000) { /* |x| < 2^23 */
  57                 /* add and subtract a power of two to round x to an integer */
  58 #if defined(__sparc) || defined(__amd64)
  59                 yy.i = (xx.i & 0x80000000) | 0x4b000000;
  60 #elif defined(__i386)
  61                 /* assume 64-bit precision */
  62                 yy.i = (xx.i & 0x80000000) | 0x5f000000;
  63 #else
  64 #error Unknown architecture
  65 #endif
  66                 x = (x + yy.f) - yy.f;
  67 
  68                 /*
  69                  * on LP32 architectures, we can just convert x to a 32-bit
  70                  * integer and sign-extend it
  71                  */
  72                 return ((long) x);
  73         }
  74 
  75         /* now x is nan, inf, or integral */
  76         return ((long long) x);
  77 }