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 /*
  31  * log2l(x)
  32  * RETURN THE BASE 2 LOGARITHM OF X
  33  *
  34  * Method:
  35  *      purge off 0,INF, and NaN.
  36  *      n = ilogb(x)
  37  *      if (n<0) n+=1
  38  *      z = scalbn(x,-n)
  39  *      LOG2(x) = n + (1/ln2)*log(x)
  40  */
  41 
  42 #pragma weak log2l = __log2l
  43 
  44 #include "libm.h"
  45 #include "longdouble.h"
  46 
  47 static const long double
  48         zero    = 0.0L,
  49         half    = 0.5L,
  50         one     = 1.0L,
  51         invln2  = 1.442695040888963407359924681001892137427e+0000L;
  52 
  53 long double
  54 log2l(long double x) {
  55         int n;
  56 
  57         if (x == zero || !finitel(x))
  58                 return (logl(x));
  59         n = ilogbl(x);
  60         if (n < 0)
  61                 n += 1;
  62         x = scalbnl(x, -n);

  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 /*
  31  * log2l(x)
  32  * RETURN THE BASE 2 LOGARITHM OF X
  33  *
  34  * Method:
  35  *      purge off 0,INF, and NaN.
  36  *      n = ilogb(x)
  37  *      if (n<0) n+=1
  38  *      z = scalbn(x,-n)
  39  *      LOG2(x) = n + (1/ln2)*log(x)
  40  */
  41 
  42 #pragma weak __log2l = log2l
  43 
  44 #include "libm.h"
  45 #include "longdouble.h"
  46 
  47 static const long double
  48         zero    = 0.0L,
  49         half    = 0.5L,
  50         one     = 1.0L,
  51         invln2  = 1.442695040888963407359924681001892137427e+0000L;
  52 
  53 long double
  54 log2l(long double x) {
  55         int n;
  56 
  57         if (x == zero || !finitel(x))
  58                 return (logl(x));
  59         n = ilogbl(x);
  60         if (n < 0)
  61                 n += 1;
  62         x = scalbnl(x, -n);