First Play PGC and Pre Commands

[hoops10]

What exactly are the Pre Commands and what do they mean. I want my movie to go directly to the main menu when first inserted. I think I know how to do that but my question is what do these Pre Commands mean:

1. Pre Command Set GPreg<8> mov (set-val)<1>
2. Pre Command Set GPreg<15> mov (set-val)<0>
3. Pre Command (JumpSS VMGM) Jump to VMG PGC: 1

I pretty sure I know that the last pre command loads up the main menu, but what about the first two? Thanks.

[hoops10]

After doing some research, I think I may have found what those 2 Pre Commands do. They deal with RCE Protection and making the disc Region 1. I found this info at IFOEdit's web site. IF I am wrong, please correct me. Thanks.