Assembler Guru's.

[Ward]

The jumps you refer to are proably to $5800 and about 5 0r 6 near addresses
?

These are jumps to the GM "Heads Up" system. If you look again you will fine
them at the very end of a specifie function, like the final part of spark
calculation, It will call with the value of spark aftea all bias and
corrections have been summed. The heads up can then add or subtract spark as
the user desires. Other functions are AFR, EGR, TCC, etc. 

Ward

On Fri, 09 Jul 1999 02:52:37 -0800, Ludis Langens wrote:

> Ross Myers wrote:
> > 
> > Been flicking through the code of some Holden stuff lately, and came
across
> > the following, can any of you figure what this maybe used for, This
code
> > structure continues for a fair while and occasionally jumps to some
other
> > running code at $5xxx. An example -
> >[...]
> > 183C STAA  $0488
> 
> It is obviously collecting together boolean flags from various scattered
> locations.  This could be for an output port, or maybe for an ALDL
> status byte.  What is at location $0488?  If nothing, it might be meant
> for use during engine calibration.  A set of 8 LEDs might be driven from
> a port placed at that location.
> 
> What is at $5xxx in your ECM?  Is that in your 64Kbyte EPROM?  In many
> ECMs, that address range is GM's favorite place to hook in their
> development tools.
> 
> -- 
> Ludis Langens                               ludis (at) cruzers (dot) com
> Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/





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