[Libre-soc-dev] svp64 review

Jacob Bachmeyer jcb62281 at gmail.com
Tue Jul 26 06:15:26 BST 2022

Jacob Lifshay wrote:
> On Mon, Jul 25, 2022, 18:48 Jacob Bachmeyer via Libre-soc-dev 
> <libre-soc-dev at lists.libre-soc.org 
> <mailto:libre-soc-dev at lists.libre-soc.org>> wrote:
>     I am looking at the "Power ISA[TM] Version 3.1B" publicly
>     available from
>     the OpenPOWER Foundation's Web site.  The Preface defines four
>     "Compliancy Subsets" each of which builds on the lower levels.  BE is
>     optional for every subset except for the "AIX Compliancy Subset
>     (ACS)"
>     which is the highest level.
> In v3.1B in the list of Scalar Float Optional Features (page 13):
> > Little Endian (LE)
> > (BE is required for SFFS and SFS. Linux
> > supporting SFFS and SFS is 32b BE
> > Linux.)

Yes, I later noticed that I had misread that and there are apparently 
two different Power ISA Linux ports:  32-bit BE and 64-bit LE.  AIX 
apparently requires *both* endians to be supported.  In my defense, I 
had missed that SFFS and SFS were the abbreviations for the lower two 

(In retrospect, obviously if one mode is optional, the other has to be 

-- Jacob

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