Ah.. I forgot the division operation. It is just division operation for D3 format you can write like below. For instance:

before:
D3DXVec4Divide(vec,vec.w);
after:
//D3DXVec4Divide(vec,vec.w);
vec.x /=vec.w;
vec.y /=vec.w;
vec.z /=vec.w;