usr/src/lib/libc/sparcv9/fp/_Qp_uxtoq.c

   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, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 1994-1997, by Sun Microsystems, Inc.
  24  * All rights reserved.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include "quad.h"
  30
  31 /*
  32  * _Qp_uxtoq(pz, x) sets *pz = (long double)x.
  33  */
  34 void
  35 _Qp_uxtoq(union longdouble *pz, unsigned long x)
  36 {
  37         unsigned int    e;
  38
  39         /* test for zero */
  40         if (x == 0) {
  41                 Z.l.msw = Z.l.frac2 = Z.l.frac3 = Z.l.frac4 = 0;
  42                 QUAD_RETURN(Z);
  43         }
  44
  45         /* find the most significant bit */
  46         for (e = 63; (x & (1l << e)) == 0; e--)
  47                 ;
  48
  49         if (e > 48) {
  50                 Z.l.msw = (x >> (e - 16)) & 0xffff;
  51                 Z.l.frac2 = x >> (e - 48);
  52                 Z.l.frac3 = x << (80 - e);
  53         } else if (e > 16) {
  54                 Z.l.msw = (x >> (e - 16)) & 0xffff;
  55                 Z.l.frac2 = x << (48 - e);
  56                 Z.l.frac3 = 0;
  57         } else {
  58                 Z.l.msw = (x << (16 - e)) & 0xffff;
  59                 Z.l.frac2 = Z.l.frac3 = 0;
  60         }
  61         Z.l.frac4 = 0;
  62         Z.l.msw |= ((e + 0x3fff) << 16);
  63         QUAD_RETURN(Z);
  64 }