lib/libc/stdlib/erand48.c

   1 /*      $NetBSD: erand48.c,v 1.9 2006/03/22 20:52:16 drochner Exp $     */
   2
   3 /*
   4  * Copyright (c) 1993 Martin Birgmeier
   5  * All rights reserved.
   6  *
   7  * You may redistribute unmodified or modified versions of this source
   8  * code provided that the above copyright notice and this and the
   9  * following conditions are retained.
  10  *
  11  * This software is provided ``as is'', and comes with no warranties
  12  * of any kind. I shall in no event be liable for anything that happens
  13  * to anyone/anything when using this software.
  14  */
  15
  16 #include <sys/cdefs.h>
  17 #if defined(LIBC_SCCS) && !defined(lint)
  18 __RCSID("$NetBSD: erand48.c,v 1.9 2006/03/22 20:52:16 drochner Exp $");
  19 #endif /* LIBC_SCCS and not lint */
  20
  21 #include "namespace.h"
  22
  23 #include <assert.h>
  24 #include <math.h>
  25
  26 #include "rand48.h"
  27
  28 #ifdef __weak_alias
  29 __weak_alias(erand48,_erand48)
  30 #endif
  31
  32 double
  33 erand48(unsigned short xseed[3])
  34 {
  35
  36         _DIAGASSERT(xseed != NULL);
  37
  38         __dorand48(xseed);
  39         return ldexp((double) xseed[0], -48) +
  40                ldexp((double) xseed[1], -32) +
  41                ldexp((double) xseed[2], -16);
  42 }