CUDA & D3D

Hi All. In SimpleD3DTexture example from SDK they create texture 256x256. When cudaD3D9ResourceGetMappedSize is called, 1024*1024 is returned. Also cudaD3D9ResourceGetMappedPitch returns 4096. I supposed pitch for 256 x 256 texture should be 256 * 4 = 1024 and mapped size 256 * 256 * 4.