directx - Bitwise operators in DX9 ps_2_0 shader

I've got the following code in a shader:

// v & y are both uints
nPixel = v;
nPixel << 8;
nPixel |= y;

and this gives me the following error in compilation:

shader.fx(80,10): error X3535: Bitwise operations not supported on legacy targets.
shader.fx(92,18): ID3DXEffectCompiler::CompileEffect: There was an error compiling expression

ID3DXEffectCompiler: Compilation failed

The error is on the following line:

nPixel |= y;

What am I doing wrong here?

Answer

Bitwise operations and integer operations were new for SM 4.0/DX10. As your error says:

Bitwise operations not supported on legacy targets.

You'll have to target DX10.

Alternatively, this blog post suggests using a texture to map results of AND,OR,XOR to different color channels.

bitwise operators texture: AND,OR,XOR

Seems plausible, and might be faster than the alternative I suggested in the comments.