How to write the IPUS kernel?

[435761040]

I want a raw8 to RGB888 ISP kernel now.

Is there such a thing in Curry? If not, how to rewrite it?
  Lsr luta, ina0, 4 //raw data: 16bit with 0 in low 4 bit
Is this 12?
Is that 8 bit like this?
  Lsr luta, ina0, 8