From: lkcl Date: Sat, 9 Apr 2022 20:37:26 +0000 (+0100) Subject: (no commit message) X-Git-Tag: opf_rfc_ls005_v1~2819 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8f96f27b25d67501e38efed0abe460f0c23f92b1;p=libreriscv.git --- diff --git a/openpower/sv/svp64/appendix.mdwn b/openpower/sv/svp64/appendix.mdwn index 80b8bf5ad..bfbae889a 100644 --- a/openpower/sv/svp64/appendix.mdwn +++ b/openpower/sv/svp64/appendix.mdwn @@ -145,7 +145,9 @@ there are only 9 bits available. Thirdly, a packing format was decided: for 2R-1W an EXTRA3 indexing could have been decided that RA would be indexed 0 (EXTRA bits 0-2), RB indexed 1 (EXTRA bits 3-5) -and RT indexed 2 (EXTRA bits 6-8). +and RT indexed 2 (EXTRA bits 6-8). In some cases (LD/ST with update) +RA-as-a-source is given a **different** EXTRA index from RA-as-a-result +(because it is possible to do, and perceived to be useful). Fourthly, the instruction was analysed to see if Twin or Single Predication was suitable. As a general rule this was if there @@ -156,6 +158,14 @@ Fifthly, in an automated process the results of the analysis were outputted in CSV Format for use in machine-readable form by sv_analysis.py +Quslifying future Power ISA Scalar instructions for SVP64 +is **strongly** advised to utilise this same process and the same +sv_analysis.py program. Alterations to that same program which +change the Designation is **prohibited** once finalised (ratified +through the Power ISA WG Process). It would +be similar to deciding that `add` should be changed from X-Form +to D-Form. + # Single Predication This is a standard mode normally found in Vector ISAs. every element in every source Vector and in the destination uses the same bit of one single predicate mask.