git.sur5r.net Git - cc65/blob - src/cc65/util.c

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                  util.c                                   */
   4 /*                                                                           */
   5 /*                 Utility functions for the cc65 C compiler                 */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 1998-2004 Ullrich von Bassewitz                                       */
  10 /*               Römerstraße 52                                              */
  11 /*               D-70794 Filderstadt                                         */
  12 /* EMail:        uz@cc65.org                                                 */
  13 /*                                                                           */
  14 /*                                                                           */
  15 /* This software is provided 'as-is', without any expressed or implied       */
  16 /* warranty.  In no event will the authors be held liable for any damages    */
  17 /* arising from the use of this software.                                    */
  18 /*                                                                           */
  19 /* Permission is granted to anyone to use this software for any purpose,     */
  20 /* including commercial applications, and to alter it and redistribute it    */
  21 /* freely, subject to the following restrictions:                            */
  22 /*                                                                           */
  23 /* 1. The origin of this software must not be misrepresented; you must not   */
  24 /*    claim that you wrote the original software. If you use this software   */
  25 /*    in a product, an acknowledgment in the product documentation would be  */
  26 /*    appreciated but is not required.                                       */
  27 /* 2. Altered source versions must be plainly marked as such, and must not   */
  28 /*    be misrepresented as being the original software.                      */
  29 /* 3. This notice may not be removed or altered from any source              */
  30 /*    distribution.                                                          */
  31 /*                                                                           */
  32 /*****************************************************************************/
  33
  34
  35
  36 #include "util.h"
  37
  38
  39
  40 /*****************************************************************************/
  41 /*                                   Code                                    */
  42 /*****************************************************************************/
  43
  44
  45
  46 int PowerOf2 (unsigned long Val)
  47 /* Return the exponent if val is a power of two. Return -1 if val is not a
  48  * power of two.
  49  */
  50 {
  51     int I;
  52     unsigned long Mask = 0x0001;
  53
  54     for (I = 0; I < 32; ++I) {
  55         if (Val == Mask) {
  56             return I;
  57         }
  58         Mask <<= 1;
  59     }
  60     return -1;
  61 }