cubic_conv
w0 = F2I(f_h + 512 * cubic_conv(f_a, I2F(512 + weight) / 512));
w1 = F2I(f_h + 512 * cubic_conv(f_a, I2F(0 + weight) / 512));
w2 = F2I(f_h + 512 * cubic_conv(f_a, I2F(512 - weight) / 512));
w3 = F2I(f_h + 512 * cubic_conv(f_a, I2F(1024 - weight) / 512));