shf_op
u16 areg, enum shf_op op, u16 breg, bool i8, bool sw, bool wr_both,
swreg lreg, enum shf_op op, swreg rreg, enum shf_sc sc, u8 shift)
swreg lreg, enum shf_op op, swreg rreg, enum shf_sc sc)