From: lkcl Date: Mon, 11 Dec 2023 02:51:30 +0000 (+0000) Subject: (no commit message) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e669f099abf841d43948a828003693d1506c2501;p=libreriscv.git --- diff --git a/openpower/sv/normal.mdwn b/openpower/sv/normal.mdwn index f2ead2270..21bc84066 100644 --- a/openpower/sv/normal.mdwn +++ b/openpower/sv/normal.mdwn @@ -214,6 +214,13 @@ such as crand, cror or [[sv/cr_int_predication]] crweirder may be used, and ffirst applied to the crop instead of to the arithmetic vector. Note that crops are covered by the [[sv/cr_ops]] Mode format. +Important to note is that reduce mode is implied by Data-Dependent Fail-First. +In other words where normally if the destination is Scalar, the looping +terminates at the first result, Data-Dependent Fail-First *continues* +just as it does in reduce mode. This allows effectively *conditional* +reduction (one register is both a source and destination) where testing of +each result gives an option to exit. + Use of Fail-on-first with Vertical-First Mode is not prohibited but is not really recommended. The effect of truncating VL may have unintended and unexpected consequences on subsequent instructions.