thoughts and questions on 8xx patches
dan at embeddededge.com
Tue Sep 21 16:37:23 EST 2004
On Sep 20, 2004, at 8:15 PM, Robert P. J. Day wrote:
> 1) what does it mean to have two different areas for the microcode
> patch in DPRAM?
It means that's where the microcode was built to run.
> and it would be useful to understand to know why the SMC patch
> writes a little info into offset 0x2e00 and far more into 0x2f00,
You would have to ask the person that wrote it.
> 2) is the cpm_load_patch() routine justified in assuming that,
> regardless of the patch, there will *always* be a 0x2000 and 0x2f00
> array to load?
No, it was just done that way because that is the microcode we
had to load and that's where it belonged.
> apart from the underlying magic, are there *any* rules that patches
> have to follow,
You can only run one patch at a time.
> (as an aside, you didn't comment on a couple of other things, so i'm
> not sure if they had any validity. that is, what is obviously a bad
> value for RPBASE,
The only comment I can make is there have been several different
of CPM roms on the different processor variants, the microcode patches
specific to those, and perhaps the last change was for a specific
that doesn't match what you have.
Various IIC/SMC relocation patches have been used, and the USB SOF
patch has been used on the various processors. At the time they were
used, they worked.
> if patches aren't going away any time soon, then it only makes sense
> to make their selection as simple and as comprehensible as possible,
> and not require the user to actually edit files to define selection
> macros for them.
If you have the patches and can test them, go for it.
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