It occurs to me that SCA, SCAS, GETXACC, and XORO32 have an issue from a discovery perspective. All four instructions stuff a value into the next instructions S register, but the subsequent instruction doesn't look any different. In other words, it is not immediately obvious that "something else" is going on. I am not suggesting that the instructions should be changed, mind you. Instead, I'm thinking that there should be some means to easily indicate this in the code. But a particular recommendation escapes me. I know the old "0-0" trick for P1 might work, but it doesn't feel like a real solution. So, for now, I'm just putting it out there for discussion.