def get_next_double(context, builder, state_ptr):
    """
    Get the next double generated by the PRNG at *state_ptr*.
    """
    # a = rk_random(state) >> 5, b = rk_random(state) >> 6;
    a = builder.lshr(get_next_int32(context, builder, state_ptr), const_int(5))
    b = builder.lshr(get_next_int32(context, builder, state_ptr), const_int(6))

    # return (a * 67108864.0 + b) / 9007199254740992.0;
    a = builder.uitofp(a, double)
    b = builder.uitofp(b, double)
    return builder.fdiv(
        builder.fadd(b, builder.fmul(a, ir.Constant(double, 67108864.0))),
        ir.Constant(double, 9007199254740992.0))

    Get the next double generated by the PRNG at *state_ptr*.
    
numba/cpython/randomimpl.py