Ejemplo n.º 1
0
static double
get_double_rshift(VALUE x, size_t *pnumbits)
{
    size_t numbits;

    if (RB_BIGNUM_TYPE_P(x) && BIGNUM_POSITIVE_P(x) &&
            DBL_MAX_EXP <= (numbits = rb_absint_numwords(x, 1, NULL))) {
        numbits -= DBL_MANT_DIG;
        x = rb_big_rshift(x, SIZET2NUM(numbits));
    }
    else {
	numbits = 0;
    }
    *pnumbits = numbits;
    return Get_Double(x);
}
Ejemplo n.º 2
0
static VALUE
math_log10(VALUE obj, VALUE x)
{
    double d;
    size_t numbits;

    if (RB_BIGNUM_TYPE_P(x) && BIGNUM_POSITIVE_P(x) &&
            DBL_MAX_EXP <= (numbits = rb_absint_numwords(x, 1, NULL))) {
        numbits -= DBL_MANT_DIG;
        x = rb_big_rshift(x, SIZET2NUM(numbits));
    }
    else {
	numbits = 0;
    }

    d = Get_Double(x);
    /* check for domain error */
    if (d < 0.0) domain_error("log10");
    /* check for pole error */
    if (d == 0.0) return DBL2NUM(-INFINITY);

    return DBL2NUM(log10(d) + numbits * log10(2)); /* log10(d * 2 ** numbits) */
}