title: What are pseudo-instructions for in gem5?
body: <p>So, I was seeing how some simulations in gem5 are implemented, more specifically, I was having a look at PIMSim (<a href="https://github.com/vineodd/PIMSim" rel="nofollow noreferrer">https://github.com/vineodd/PIMSim</a>). I saw they had implemented some pseudo-instructions for the x86 architecture. I have seen these pseudo-instructions are only used in full system mode. For that they have modified the following files:</p>
  <ul>
  <li>include/gem5/m5ops.h</li>
  <li>util/m5/m5op_x86.S</li>
  <li>src/arch/x86/isa/decoder/two_byte_opcodes.isa</li>
  <li>src/sim/pseudo_inst.hh(cc)</li>
  </ul>
  <p>I have understood what changes are neccessary to implement a custom pseudo-instruction, but what I do not understand is what they are and how they are used. I do not find any place outside these files this functions are called. Any help? Thanks in advance!</p>