From d4d882496dfba26f945e7dabc70de693807a0e7e Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Thu, 26 Apr 2018 09:17:43 +0100 Subject: [PATCH] start filling in --- isa_conflict_resolution.mdwn | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/isa_conflict_resolution.mdwn b/isa_conflict_resolution.mdwn index d72c0a54e..1002440fd 100644 --- a/isa_conflict_resolution.mdwn +++ b/isa_conflict_resolution.mdwn @@ -235,6 +235,22 @@ separate page? review this para?**) TBD paraphrase and clarify +Coming out of the software-related proposal by Jacob, which hinged on +the idea of a global gcc / binutils database that kept and coordinated +architectural encodings, was to quite simply make the mvendorid and +marchid CSRs have WARL (writeable) characteristics. For instances +where mvendorid and marchid are readable, that would be taken to be +a Standards-mandatory "declaration" that the architecture has *no* +Custom Extensions. + +This incredibly simple non-invasive idea has some unique and distinct +advantages over other proposals: + +* Existing designs - even though the specification is not finalised + (but has "frozen" aspects) - would be completely unaffected: the + change is to the "wording" of the specification to "retrospectively" + fit reality. + > In an earlier part of the thread someone kindly pointed out that MISA > already switches out entire sets of instructions [which interacts at the > "decode" phase]. However it was noted after a few days of investigating -- 2.30.2