usr/src/lib/libm/common/R/log10f.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 (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  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  23  */
  24 /*
  25  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  26  * Use is subject to license terms.
  27  */
  28
  29 #pragma weak __log10f = log10f
  30
  31 #include "libm.h"
  32
  33 static const float zero = 0.0f, mone = -1.0f;
  34
  35 float
  36 log10f(float x) {
  37         int     hx, ix;
  38         float   w;
  39
  40         hx = *(int *)&x;
  41         ix = hx & ~0x80000000;
  42         if (ix > 0x7f800000)
  43                 return (x * x);
  44         if (ix == 0x7f800000)
  45                 return (x + x * x);
  46         if (ix == 0) {
  47                 w = mone;
  48                 return (w / zero);
  49         }
  50         if (hx < 0) {
  51                 w = zero;
  52                 return (w / zero);
  53         }
  54         return ((float)log10((double)x));
  55 }