Now what?

[Marc Randolph]

On Tue, May 25, 1999 at 04:39:27PM -0400, Bruce Plecan wrote:
> 
> OK, for grins lets make believe I got something that says what the ALDL code
> looks like, ie the list of erroe codes first, how does that get me from
> where I am?, to reading code?.

Reading code can be kinda tough, especially when starting from scratch.

Probably the easiest way to get started is to use the ALDL output 
data to make a table of which memory locations hold what values 
(ie, if you know what most of the bytes of the ALDL data stream
mean, you can map that back to a memory location in the code).
It won't be a complete list, but it'll be a [small] start to let you
start commenting the code on what gets used where.  

What you'll find is that TPS, coolant, and RPM are used ALL OVER
the place - almost so much that you'll wonder if it'll ever make 
sense.  If you know some of the table lookup values for various
parameters, you can search the code for where the table value is 
accessed - bingo, the code around that area probably has to do with
that function.  You can either prove or disprove that theory by
studying the code in that area and looking at other table values in
that area to see if they correspond to parameters you would expect
for that function.

Speaking of theories, I didn't hear back from anyone on my theory that
the P6 processor, if it is a 16 bit processor, is backwards compatible
with the P4.  Does anyone know any details on the P6?

   Marc


> | I am not familiar with Gcar.  What you really need is the description
> | of the ALDL outputed data stream.  THen you figure out what code
> | outputs the ALDL data, and you figure out where that code gets the
> | data from.  At the point you know where the data came from, you know
> | where some of the internal data is stored.  From that you can
> | generally figure out where some of the related data is gotten from, or
> | stored to.
> | Roger

-- 
  Marc Randolph     -    mrand at pobox.com    -     PGP keyID: 0x4C95994D