[yocto] TUNE_PKGARCH for Microblaze

[Khem Raj]

On Mar 19, 2013, at 9:08 PM, Sipke Vriend <sipke.vriend at xilinx.com> wrote:

> Hi all,
>  
> We are seeking some feedback regarding common practices for defining TUNE_PKGARCH within Yocto.
>  

usually its dictated by architecture, ABI and other processor features. the current tune files have good ways to express the relationships 
you would translate the below table into set of TUNE_FEATURES and define PACKAGE_EXTRA_ARCHS if you need to express compatibility between different tunes

Look at arm tunes they are the best examples of complexity

> We need to define a unique TUNE_PKGARCH for the possible configuration of Microblaze architecture.
> Our proposal is short unique string for each HW feature which is enabled in Microblaze.
>  
> For ‘extensive hardware usage’ architecture, this would result in something like:
> mbebv730-bs-mh-div-fb-cmp
> mbebv840-bs-mh-div-fb-cmp-re
> mbelv840-bs-ml-div-fe-cmp-re
> and for architecture with no ‘hardware usage’:
> mbebv730
> mbebv840
> mbelv840
>  
> The table below details the unique strings and their relation to compiler and hardware flags, and a couple of versions of Microblaze architecture.
> (If this table does not show cleanly switch to fixed width font)
> -------------------
> String Compiler Flag        Hardware Flag         CPU versions
>        -mcpu=vX.YY.Z                              v7.30.a v8.40.a
>  
> mbel   -mlittle-endian      C_ENDIANNESS (LITTLE) -       o
> mbeb   -mbig-endian         C_ENDIANNESS (BIG)    x       o
>  
> bs     -mxl-barrel-shift    C_USE_BARREL          o       o
>  
> ml     -mnoxl-soft-mul      C_USE_HW_MUL (MUL32)  o       o
> mh     -mxl-multiply-high   C_USE_HW_MUL (MUL64)  o       o
>  
> div    -mnoxl-soft-div      C_USE_DIV             o       o
>  
> fb     -mhard-float         C_USE_FPU (BASIC)     o       o
> fe     -mxl-float-convert   C_USE_FPU (EXTENDED)  o       o
> fe     -mxl-float-sqrt      C_USE_FPU (EXTENDED)  o       o
>  
> cmp   -mxl-pattern-compare  C_USE_PCMP_INSTR      o       o
>  
> re    -mxl-reorder          C_USE_REORDER_INSTR   -       o
>  
> Where ‘–‘ means unavailable ‘x’ is only option and ‘o’ is optional.
> -------------------
>  


you can express this with TUNECONFLICTS and TUNEVALID

and may be create heirarchy of tune files which builds upon common tunings.

> Note the table rows have hardware feature ‘groupings’, which means only one of the strings should be present within the TUNE_PKGARCH. For example the Floating Point Unit hardware feature can be defined by either fb (for basic mode) or fe (for extended mode).
>  
> Regards
> Sipke
>  
>  
>  
> 
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