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glibc  2.9
Functions | Variables
s_scalbnl.c File Reference
#include "math.h"
#include "math_private.h"
#include <math_ldbl_opt.h>

Go to the source code of this file.

Functions

long double __scalbnl (long double x, int n)
 long_double_symbol (libc, __scalbnl, scalbnl)

Variables

static long double twolm54 = 5.55111512312578270212e-17
static long double huge = 1.0E+300L
static long double tiny = 1.0E-300L
static double two54 = 1.80143985094819840000e+16
static double twom54 = 5.55111512312578270212e-17

Function Documentation

long double __scalbnl ( long double  x,
int  n 
)

Definition at line 51 of file s_scalbnl.c.

{
       int64_t k,l,hx,lx;
       union { int64_t i; double d; } u;
       GET_LDOUBLE_WORDS64(hx,lx,x);
       k = (hx>>52)&0x7ff;         /* extract exponent */
       l = (lx>>52)&0x7ff;
       if (k==0) {                        /* 0 or subnormal x */
           if (((hx|lx)&0x7fffffffffffffffULL)==0) return x; /* +-0 */
           u.i = hx;
           u.d *= two54;
           hx = u.i;
           k = ((hx>>52)&0x7ff) - 54;
       }
       else if (k==0x7ff) return x+x;            /* NaN or Inf */
       k = k+n;
       if (n> 50000 || k > 0x7fe)
         return huge*__copysignl(huge,x); /* overflow */
       if (n< -50000) return tiny*__copysignl(tiny,x); /*underflow */
       if (k > 0) {                       /* normal result */
           hx = (hx&0x800fffffffffffffULL)|(k<<52);
           if ((lx & 0x7fffffffffffffffULL) == 0) { /* low part +-0 */
              SET_LDOUBLE_WORDS64(x,hx,lx);
              return x;
           }
           if (l == 0) { /* low part subnormal */
              u.i = lx;
              u.d *= two54;
              lx = u.i;
              l = ((lx>>52)&0x7ff) - 54;
           }
           l = l + n;
           if (l > 0)
              lx = (lx&0x800fffffffffffffULL)|(l<<52);
           else if (l <= -54)
              lx = (lx&0x8000000000000000ULL);
           else {
              l += 54;
              u.i = (lx&0x800fffffffffffffULL)|(l<<52);
              u.d *= twom54;
              lx = u.i;
           }
           SET_LDOUBLE_WORDS64(x,hx,lx);
           return x;
       }
       if (k <= -54)
         return tiny*__copysignl(tiny,x);        /*underflow*/
       k += 54;                           /* subnormal result */
       lx &= 0x8000000000000000ULL;
       SET_LDOUBLE_WORDS64(x,(hx&0x800fffffffffffffULL)|(k<<52),lx);
       return x*twolm54;
}

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long_double_symbol ( libc  ,
__scalbnl  ,
scalbnl   
)

Variable Documentation

long double huge = 1.0E+300L [static]

Definition at line 38 of file s_scalbnl.c.

long double tiny = 1.0E-300L [static]

Definition at line 39 of file s_scalbnl.c.

double two54 = 1.80143985094819840000e+16 [static]

Definition at line 45 of file s_scalbnl.c.

long double twolm54 = 5.55111512312578270212e-17 [static]

Definition at line 37 of file s_scalbnl.c.

double twom54 = 5.55111512312578270212e-17 [static]

Definition at line 46 of file s_scalbnl.c.