static float full_pow2f(float p)
{
    float result;
    asm(
        "fld %1;"
        "fld1;"
        "fscale;"
        "fstp %0;"
    : "=m" (result)
    : "m" (p)
    : "%st(1)");
    return result;
}

static float frac_pow2f(float p)
{
    float result;
    asm(
        "fld1;"
        "fld %1;"
        "fprem;"
        "f2xm1;"
        "faddp %%st(0), %%st(1);"
        "fstp %0;"
        : "=m" (result)
        : "m" (p)
        : "%st(1)"
    );
    return result;
}

static float pow2f(float p)
{
    return full_pow2f(p) * frac_pow2f(p);
}