Re: Porting question

[Yoshinori Sato <ysato at users dot sourceforge dot jp>]

It is a H8/300 archtecture support author.

At Sat, 29 Mar 2003 08:48:30 +0100,
Uwe Kindler wrote:
> 
> Hello,
> 
> i started porting the eCOS HAL for the Hitachi H8S 2357 for our company. I
> thought the H8S26xx variant HAL would be a good starting point for my port.
> I carefully read the source code of the H8S26xx HAL port, wich is a variant
> of the H8300 architecture. Now I'm not sure whether the H8S series is really
> a variant of the H8300 architecture or if it is a new architecture.

I think that H8S is an article upper compatible with H8/300H.
I think that I can understand the thing if I read both materials carefully.

> Important things like HAL_SavedRegisters or HAL_THREAD_LOAD_CONTEXT,
> HAL_THREAD_SWITCH_CONTEXT are implement within the H8S variant (and not in
> architecture HAL like stated in porting guide) because it differs in
> register- and stack-structure from the H8300. And there are some more
> differences between the H8300 and the H8S series.

It is possible technically to make this part compatible.
However, it is not the best as implementation of H8S HAL.

> Now I would like to know your opinion - if two processor families differ in
> register structure and stack structure like the H8S and H8300, would it be
> better to create a new architecture HAL H8S (and then single variants for
> the single family members i.e H8S2357, H8S2128, H8S2633...) or would it be
> better to ceate the H8S port as a new variant of the H8300 architecture.

I decided that there was many it a common part than a strange part.
As a result I did it and supported H8S by addition of variant instead 
of addition of new architecture.

-- 
Yoshinori Sato
<ysato at users dot sourceforge dot jp>