s_scalbn.c File Reference

#include "math_libm.h"
#include "math_private.h"
#include <limits.h>

Include dependency graph for s_scalbn.c:

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Functions
double	scalbln (double x, long n)
	libm_hidden_def (scalbln)

Variables
static const double	two54 = 1.80143985094819840000e+16
static const double	twom54 = 5.55111512312578270212e-17
static const double	huge = 1.0e+300
static const double	tiny = 1.0e-300

Function Documentation

libm_hidden_def

(

scalbln

)

Definition at line 62 of file s_scalbn.c.

References scalbln().

{
        return scalbln(x, n);
}

double scalbln	(	double	x,
		long	n
	)

Definition at line 29 of file s_scalbn.c.

References copysign(), EXTRACT_WORDS, GET_HIGH_WORD, huge, k, SET_HIGH_WORD, tiny, two54, and twom54.

Referenced by libm_hidden_def().

{
        int32_t k, hx, lx;

        EXTRACT_WORDS(hx, lx, x);
        k = (hx & 0x7ff00000) >> 20; /* extract exponent */
        if (k == 0) { /* 0 or subnormal x */
                if ((lx | (hx & 0x7fffffff)) == 0)
                        return x; /* +-0 */
                x *= two54;
                GET_HIGH_WORD(hx, x);
                k = ((hx & 0x7ff00000) >> 20) - 54;
        }
        if (k == 0x7ff)
                return x + x; /* NaN or Inf */
        k = k + n;
        if (k > 0x7fe)
                return huge * copysign(huge, x); /* overflow */
        if (n < -50000)
                return tiny * copysign(tiny, x); /* underflow */
        if (k > 0) { /* normal result */
                SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
                return x;
        }
        if (k <= -54) {
                if (n > 50000) /* in case integer overflow in n+k */
                        return huge * copysign(huge, x); /* overflow */
                return tiny * copysign(tiny, x); /* underflow */
        }
        k += 54; /* subnormal result */
        SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
        return x * twom54;
}

Variable Documentation

const double huge = 1.0e+300

static

Definition at line 26 of file s_scalbn.c.

Referenced by scalbln().

const double tiny = 1.0e-300

static

Definition at line 27 of file s_scalbn.c.

Referenced by scalbln().

const double two54 = 1.80143985094819840000e+16

static

Definition at line 24 of file s_scalbn.c.

Referenced by scalbln().

const double twom54 = 5.55111512312578270212e-17

static

Definition at line 25 of file s_scalbn.c.

Referenced by scalbln().