The LT5 has 4 VE tables w 4 corresponding Offset constants. I have run into an issue where one copy of the .xdf uses 1 byte, while another uses 2. So I can use the 2 .xdfs, with 2 different addresses (one being -1 of the other) and read the same bin correctly. Can someone answer if the VE Offset is a 1 or 2 byte
item? I imagine GM handled it the same way for other masks. This is true for all the LT5 masks.
A sample of this:
$D0A 9B3 and 9B4
BPPA is stock bin

 

Is there a documented disassembly out there? It's easy to check off that.

 

I do not have one. Its odd because there are several .xdfs for it, and some use
1 byte while others use 2.

 

If you can find one from a similar year you can use it to quickly reverse engineer the correct one and find out what’s actually being pulled by the subroutine when it’s time.

 

The offset is a 2 byte value. The reason it looks OK with the wrong XDF is that the calibrations I've looked at, GM uses the decimal value of 100 for the offset (39%). As long as the offset is lower then 256 it all fits into the LSB.

RBob.

 

This is the assumption I had made, I guess my brain still works.

 

Thanks RBob. As usual always very helpful. I think some of the earlier .xdfs had used the 1 byte but later ones correctly use the 2byte.