|Microsoft DirectX 9.0|
A programmable pixel shader is made up of a set of instructions that operate on pixel data. Registers transfer data in and out of the ALU. Additional control can be applied to modify the instruction, the results, or what data gets written out.
Add a face register. Add a position register. Color registers (v#) are now fully floating point and the texture coordinate registers (t#) have been consolidated. Input declarations take the usage names, and multiple usages are permitted for components of a given register.
The number of temporary registers supported is 32.
Arbitrary swizzle is supported. See Arbitrary Swizzle.
Instruction predication is supported. See Predicate.
There are no dependent read limits.
There is no limit on texture instructions.
Each pixel shader is allowed anywhere from 512 up to the number of slots in the MaxPixelShader30InstructionSlots member of D3DCAPS9 (not more than 32768). The number of instructions run can be much higher because of the looping support. The MaxPShaderInstructionsExecuted cap in D3DCAPS9 should be at least 2^16.