[openrisc] Re: [ECOS] Re: OpenRISC eCos package

[Jonathan Larmour <jifl@eCosCentric.com>]

Scott Furman wrote:
> This all goes to the issue you raise above as to whether or not variant 
> subdirs are appropriate for OpenRISC, but the short answer is that, 
> since there was only one variant at the time I ported eCos, I didn't 
> make the effort to create a separate variant for the feature.  Also,

[ Ignoring Bart's option (c) for the moment since unfortunately it doesn't 
yet exist... ]

You don't need variant HALs for each configurable hardware subsystem, 
cache, FPU, etc.... you just need to make the stuff in the architecture 
HAL configurable. You could use CDL to do this naturally, and a specific 
platform could specify "requires" statements for features it knows it has, 
say FPU support or not.

But also, not all the configuration has to be done by CDL. It's also 
reasonable to define the features just with standard C preprocessor macros.

I suggest taking a look at the eCos SuperH HAL which has a similar problem 
due to the way many features can be mixed and matched, and the quite large 
but overlapping differences between SH2, SH3 and SH4. But only _some_ of 
that configuration is done via CDL. Although SH isn't configurable in the 
same way, it's solving a virtually identical problem.

Jifl
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eCosCentric    http://www.eCosCentric.com/    The eCos and RedBoot experts
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