newlib/libm/math/wf_log10.c

   1 /* wf_log10.c -- float version of w_log10.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 /*
  17  * wrapper log10f(X)
  18  */
  19
  20 #include "fdlibm.h"
  21 #include <errno.h>
  22
  23 #ifdef __STDC__
  24         float log10f(float x)           /* wrapper log10f */
  25 #else
  26         float log10f(x)                 /* wrapper log10f */
  27         float x;
  28 #endif
  29 {
  30 #ifdef _IEEE_LIBM
  31         return __ieee754_log10f(x);
  32 #else
  33         float z;
  34         z = __ieee754_log10f(x);
  35         if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
  36         if(x<=0.0f) {
  37             if(x==0.0f) {
  38                 /* log10f(0) */
  39                 errno = ERANGE;
  40                 return -HUGE_VALF;
  41             } else {
  42                 /* log10f(x<0) */
  43                 errno = EDOM;
  44                 return nanf("");
  45             }
  46         } else
  47             return z;
  48 #endif
  49 }
  50
  51 #ifdef _DOUBLE_IS_32BITS
  52
  53 #ifdef __STDC__
  54         double log10(double x)
  55 #else
  56         double log10(x)
  57         double x;
  58 #endif
  59 {
  60         return (double) log10f((float) x);
  61 }
  62
  63 #endif /* defined(_DOUBLE_IS_32BITS) */