What's the best way to describe a non-operand flag field in instructions?

Hello,

I’m working with a new ISA. In this ISA, some instructions have some flag bits that control the behavior of the instruction.

If I enumerate all of the bits, there will be 2^N (N is the number of flags) instructions to write in the td file. Currently In my code,

these kind of instructions are written as “(outs Reg:$rt), (ins Reg:$rs, Reg:$rd, Flag:$flag)” and there is another method to
decode the flag and print it to asm. However, I think it not so elegant, and I can not reuse it for CodeGen.

Is there any better way to work with this situation?

Thanks,
Iru