BrainSlug symbol information is stored in a simple xml format. All documents
must begin with:
    <?xml version="1.0" encoding="UTF-8"?>

This is then followed by:
<symbols>

The <symbols> element can have the attribute debug="on". If this is the case,
the BrainSlug channel will list the address of any matches against the symbols
that it finds when loading the game. This can be useful for figuring out why
the symbols don't work for a particular game.

and then one or more <symbol> elements. These have the syntax:
    <symbol name="sym_name" size="0x100" offset="0x4" >
        <data>
            4142???? 45??4748
        </data>
        <reloc type="ha" offset="0x4" symbol="reloc_sym" />
        <reloc type="lo" offset="0xc" symbol="reloc_sym" />
    </symbol>
    
Every <symbol> MUST have a name attribute which matches the name in the C source
code.
The size and offset attributes are optional. Size determines the number of
bytes that are considered part of the symbol. Offset determines the relative
location of the data to the symbol. 0x4 means that the data occurs 4 bytes AFTER
from the symbol address. This number can be negative to indicate the pattern
occurring before the symbol, though this is bad practice as it generally relies
on the symbols occurring in a set order, which may not be the case in all games.

The <data> is what the BrainSlug loader uses to find the symbol, it tries to
match the data somewhere with the games executable. The <data> tag should be
hexadecimal, but may contain ? as a wild card. This only occurs once, after the
game's `main.dol' has been loaded, so symbols in dynamically loaded files such
as `.rel' files cannot be found. Try to make the data short, ideally test it on
a few games. It's OK for the same symbol to appear lots of times with different
<data> if there are different versions of that method in different games for
example.

<reloc> tags are optional. The symbol may have one or more reloc tags, these
indicate that this symbol references other symbols. Presently the BrainSlug
loader ignores this information, but the intention is to allow it to find
symbols which are hard to find indirectly, by finding a symbol which references
the symbol. The reloc offsets are relative to the start of the symbol.
The valid types values are:
    "addr"  - full address of the relocated symbol as 4 bytes.
    "lo"    - the lowest 16 bits of the address of the symbol are in the lowest
              16 bits of the 32-bit instruction at the offset.
    "hi"    - the highest 16 bits of the address of the symbol are in the lowest
              16 bits of the 32-bit instruction at the offset.
    "ha"    - the highest 16 bits of the address of the symbol are in the lowest
              16 bits of the 32-bit instruction at the offset. The value is then
              adjusted so that if the lowest 16-bits of the symbol address would
              be treated as negative, one is added to the highest 16-bits.
    "b"     - the offset points to a branch which branches to the symbol.
    "bc"    - the offset points to a conditional branch which branches to the
              symbol.
    "sda21" - the offset points to a load instruction which loads from either r2
              or r13; the small data areas. These are special registers which
              never change, so accordingly have a special relocation.

If you're not familiar with relocations here are some rules of thumb:

Instructions like the following sequences are often used for loading global
variables. The first instruction is a "ha" relocation and the second is a "lo".
    lis r3,-32768
    lwz r4,256(r3)
    
    lis r11,-32768
    addi r11,r11,256
    
Instructions like the following sequence are rarer but are sometimes used to
load addresses. The first instruction is a "hi" relocation and the second is a
"lo". This is because ori has an unsigned argument.
    lis r3,-32768
    ori r3,r3,256

Instructions like the following ones are used to load small constants or global
variables. They are all "sda21" relocations.
    lwz r3,-32768(r2)
    stfs f0,-32768(r13)
    lfd f31,-32768(r2)

the document ends with:
    </symbol>