Init

[Darrel Taylor]

My only concern is that I have my INIT vector hard-coded at 0x59a, and I'm worried that it won't always work.

It's a good reason for concern, because INIT is always located after the system library code. Some day you'll use a statement that hasn't been used yet in the program and the library size will increase. Then INIT will be moved along with it, and it won't work anymore.

When you compile a program, the first instruction at location 0000 is a GOTO INIT.
But when MC Loader loads the program, it relocates that instruction to an address just before the bootloader code.

I don't have an 18F8722 to look at, but on an 18F452 the bootloader code starts at 0x7D84, and the GOTO gets relocated to 0x7D70.

You can see from the disassembly here, the highlighted line is where the GOTO instruction was moved to.
0x4a is the address of INIT for this test program.



So all you need to do is figure out where it gets relocated with that chip, then jump to that address, which in turn jumps to INIT.

HTH,

[Charles Linquis]

Darrel,

This is just the information I was looking for.

After I make my first million, I'll buy the rights to PBP from MELabs, and I'll be at your doorstep begging you to work for the company.


Thanks for the hundredth time.

[Charles Linquis]

If anyone else cares, the "magic address" Darrel is referring to for an 8720/8722 is 0x1fcf0 using MCLoader. Jump there, sit back and smile.

[Darrel Taylor]

Sweet!

+confirmation

Well, you get the rights to PBP, and have the ability to pay a modest salary... and I'll take that job.

Knock off some of those wish list items from 4-5 years ago.
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