From: lkcl Date: Sat, 19 Dec 2020 21:48:39 +0000 (+0000) Subject: (no commit message) X-Git-Tag: convert-csv-opcode-to-binary~1155 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9c071269cbd467502a74552bbc7697ccc11278e4;p=libreriscv.git --- diff --git a/openpower/sv/svp_rewrite/svp64.mdwn b/openpower/sv/svp_rewrite/svp64.mdwn index 122abdae7..1949fd592 100644 --- a/openpower/sv/svp_rewrite/svp64.mdwn +++ b/openpower/sv/svp_rewrite/svp64.mdwn @@ -510,7 +510,7 @@ CR element*. Greatly simplified pseudocode: CRs[8+i].gt = iregs[RT+i] > 0 ... etc -If a "cumulated" CR based analysis of results is desired (a la VSX CR6) then a followup instruction must be performed, setting "reduce" mode on the Vector of CRs, using cr ops to do so. This provides far more flexibility in analysing vectors than standard Vector ISAs. Normal Vector ISAs are typically restricted to "were all results nonzero" and "were some results nonzero". The application of mapreduce to Vectorised cr operations allows far more sophisticated analysis, particularly in conjunction with the new crweird operations see [[sv/cr_int_predication]]. +If a "cumulated" CR based analysis of results is desired (a la VSX CR6) then a followup instruction must be performed, setting "reduce" mode on the Vector of CRs, using cr ops (crand, crnor)to do so. This provides far more flexibility in analysing vectors than standard Vector ISAs. Normal Vector ISAs are typically restricted to "were all results nonzero" and "were some results nonzero". The application of mapreduce to Vectorised cr operations allows far more sophisticated analysis, particularly in conjunction with the new crweird operations see [[sv/cr_int_predication]]. Note in particular that the use of a separate instruction in this way ensures that high performance multi-issue OoO inplementations do not have the computation of the cumulative analysis CR as a bottleneck and hindrance, regardless of the length of VL.