Re: [Pocl-devel] Some run-time functions

[Carlos S. de La L. <car...@ur...>]

Hi Erik,

thanks for your contributions. Some of the questions you ask are open for discussion, as the kernel library implementation is still in a really early stage of development.

> - Is this implementation / coding style approximately acceptable?

It is all right. We do not have an "official" coding guideline for pocl (yet) but basically I tried to follow GNU Coding Standards, except in the LLVM passes where the LLVM guidelines are used.

I have seen you call the C library functions to implement the functionality. This is ok for "native" environments, but in a real device scenario, there is not going to be an underlying C library providing for example "cos" function. One possible option is to use some other embedded library (newlib?) underneath our kernel library, thought I have the feeling this might be overkill and make too big device binaries. Otherwise we would need to implement the "cos", "sin", whatever... functions completely in the kernel library.

Thoughts?

> - Since some of the code is highly repetitive, should we use a
> templating mechanism, probably built onto m4?

If it is *really* needed, then we can use it. But I am not sure how much effort it saves compared with the C preprocessor. If we want to make the system as portable as possible, it is desirable to keep dependencies to a minimum.

Can provide a (simple) example of a case in the kernel library where M4 macros would help?

> - I added explicitly vectorized functions e.g. for fabs or sqrt for
> SSE architectures; is this acceptable?

It is perfectly acceptable as long as the code works also in non-SSE architectures.

> - Should there be test cases for the run-time functions?

There is no strict rule, but of course the most test cases the better ;)

BR

Carlos