GP32 Gxb Structure

[greyghost]

I was experimenting using the new ARM assembler, FasmARM.
I finally got a working gxb. But I really don't understand what I did . I have these questions:
What are the six addresses at the start of at of a gxb used for?
What is the magic sequence used for? Only to identify the file type?
Why is there a need for so many sections, why not just .text and .data?

Please forgive me if these questions are insanely dumb. If they sound like a don't really understand what I am asking, that's because I don't. :blink: I still trying to figure stuff out.

 

[aapje89]

maybe try mr.spiv's site:
http://www.deadcoderssociety.tk/

 

[mr.mirko]

I was experimenting using the new ARM assembler, FasmARM.
I finally got a working gxb. But I really don't understand what I did . I have these questions:
What are the six addresses at the start of at of a gxb used for?
What is the magic sequence used for? Only to identify the file type?
Why is there a need for so many sections, why not just .text and .data?

Please forgive me if these questions are insanely dumb. If they sound like a don't really understand what I am asking, that's because I don't. :blink: I still trying to figure stuff out.

​

Welcome to the wonderful world of elf header....
-> http://www.devrs.com/gp32/files/gp32devfaqs.php

gxb:
.gxb* - Non-encrypted binary file. This is placed in gp32 ram starting at location 0xc000000. The entry point is the starting location and the entry is performed in ARM (not thumb) mode. Here is the header in ARM SDT format

magic sequence:
GameParks Idear of creating a nice indentify header.

Many Sections:
The main code is in .text
But the ELF File format neads a lot more sections to work properly, there are section of information, debugging informations, addional data, runtime created date, and so on.
To understand the ELF Format, i would give some geppee32 a try, and singelstep your code. And look what sections are copied to witch mem region.

Btw, youre right .text and .data should be enought in most cases.

 

[greyghost]

Ok, I'll try that, thanks very much.