#include "math_libm.h"
#include "math_private.h"

Include dependency graph for e_log10.c:

Functions
double attribute_hidden	__ieee754_log10 (double x)

Variables
static const double	two54 = 1.80143985094819840000e+16

static const double	ivln10 = 4.34294481903251816668e-01

static const double	log10_2hi = 3.01029995663611771306e-01

static const double	log10_2lo = 3.69423907715893078616e-13

static const double	zero = 0.0

Function Documentation

◆ __ieee754_log10()

double attribute_hidden __ieee754_log10 ( double x )

Definition at line 61 of file e_log10.c.

 {
         double y,z;
         int32_t i,k,hx;
         u_int32_t lx;
  
         EXTRACT_WORDS(hx,lx,x);
  
         k=0;
         if (hx < 0x00100000) {                  /* x < 2**-1022  */
             if (((hx&0x7fffffff)|lx)==0)
                 return -two54/zero;             /* log(+-0)=-inf */
             if (hx<0) return (x-x)/zero;        /* log(-#) = NaN */
             k -= 54; x *= two54; /* subnormal number, scale up x */
             GET_HIGH_WORD(hx,x);
         }
         if (hx >= 0x7ff00000) return x+x;
         k += (hx>>20)-1023;
         i  = ((u_int32_t)k&0x80000000)>>31;
         hx = (hx&0x000fffff)|((0x3ff-i)<<20);
         y  = (double)(k+i);
         SET_HIGH_WORD(x,hx);
         z  = y*log10_2lo + ivln10*__ieee754_log(x);
         return  z+y*log10_2hi;
 }