toolchain/gcc/newlib/libm/mathfp/s_log10.c

   1
   2 /* @(#)z_log10.c 1.0 98/08/13 */
   3 /******************************************************************
   4  * Logarithm
   5  *
   6  * Input:
   7  *   x - floating point value
   8  *
   9  * Output:
  10  *   logarithm of x
  11  *
  12  * Description:
  13  *   This routine returns the logarithm of x (base 10).
  14  *
  15  *****************************************************************/
  16
  17 /*
  18 FUNCTION
  19         <<log10>>, <<log10f>>---base 10 logarithms
  20
  21 INDEX
  22 log10
  23 INDEX
  24 log10f
  25
  26 ANSI_SYNOPSIS
  27         #include <math.h>
  28         double log10(double <[x]>);
  29         float log10f(float <[x]>);
  30
  31 TRAD_SYNOPSIS
  32         #include <math.h>
  33         double log10(<[x]>)
  34         double <[x]>;
  35
  36         float log10f(<[x]>)
  37         float <[x]>;
  38
  39 DESCRIPTION
  40 <<log10>> returns the base 10 logarithm of <[x]>.
  41 It is implemented as <<log(<[x]>) / log(10)>>.
  42
  43 <<log10f>> is identical, save that it takes and returns <<float>> values.
  44
  45 RETURNS
  46 <<log10>> and <<log10f>> return the calculated value.
  47
  48 See the description of <<log>> for information on errors.
  49
  50 PORTABILITY
  51 <<log10>> is ANSI C.  <<log10f>> is an extension.
  52
  53 */
  54
  55
  56 #include "fdlibm.h"
  57 #include "zmath.h"
  58
  59 #ifndef _DOUBLE_IS_32BITS
  60
  61 double
  62 _DEFUN (log10, (double),
  63         double x)
  64 {
  65   return (logarithm (x, 1));
  66 }
  67
  68 #endif /* _DOUBLE_IS_32BITS */