Adding new instruction

Placeholder github Source User
2023-01-10T11:49:37Z

Hi,
As part of my project I need to add 2 new instructions to the riscv core.
I don't find the file in which the opcodes are defined (in the SW toolchain) and I've been searching that for long time.
Can I get the path please for this file? or Alternativly, can I get the steps and files names for adding these 2 new instruction?

Thanks!