Back to index

glibc  2.9
Functions | Variables
e_log10f.c File Reference
#include "math.h"
#include "math_private.h"

Go to the source code of this file.

Functions

float __ieee754_log10f (float x)

Variables

static float two25 = 3.3554432000e+07
static float ivln10 = 4.3429449201e-01
static float log10_2hi = 3.0102920532e-01
static float log10_2lo = 7.9034151668e-07
static float zero = 0.0

Function Documentation

float __ieee754_log10f ( float  x)

Definition at line 42 of file e_log10f.c.

{
       float y,z;
       int32_t i,k,hx;

       GET_FLOAT_WORD(hx,x);

        k=0;
        if (hx < 0x00800000) {                   /* x < 2**-126  */
            if ((hx&0x7fffffff)==0)
                return -two25/(x-x);             /* log(+-0)=-inf */
            if (hx<0) return (x-x)/(x-x); /* log(-#) = NaN */
            k -= 25; x *= two25; /* subnormal number, scale up x */
           GET_FLOAT_WORD(hx,x);
        }
       if (hx >= 0x7f800000) return x+x;
       k += (hx>>23)-127;
       i  = ((u_int32_t)k&0x80000000)>>31;
        hx = (hx&0x007fffff)|((0x7f-i)<<23);
        y  = (float)(k+i);
       SET_FLOAT_WORD(x,hx);
       z  = y*log10_2lo + ivln10*__ieee754_logf(x);
       return  z+y*log10_2hi;
}

Here is the call graph for this function:

Here is the caller graph for this function:


Variable Documentation

float ivln10 = 4.3429449201e-01 [static]

Definition at line 29 of file e_log10f.c.

float log10_2hi = 3.0102920532e-01 [static]

Definition at line 30 of file e_log10f.c.

float log10_2lo = 7.9034151668e-07 [static]

Definition at line 31 of file e_log10f.c.

float two25 = 3.3554432000e+07 [static]

Definition at line 28 of file e_log10f.c.

float zero = 0.0 [static]

Definition at line 36 of file e_log10f.c.