Why doesn't MOVWF affect the status register?

I'm learning assembly, and it seems that MOVF f,d can be moved f to f, but the zero flag in the status register will be set, meaning it's useful to check if f is zero. Why doesn't MOVWF a开发者_开发问答ffect the status register?

This question probably talking about PIC MCPUs, so I have added pic tag.

PIC MCPUs have RISC architecture, which is high-optimised logic and that is the main reason why MOVWF will not to affect to the Zero flag in Status register.

When value is loaded in to W (WREG) the Zero flag in Status register is set, so there is no reason to be set again when we store that value with MOVWF instruction. This is useful in case that we must test the Zero flag after MOVWF instruction.