[Libre-soc-bugs] [Bug 689] MMU PortInterface raises addr_ok_o even on a misaligned access exception

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=689

Luke Kenneth Casson Leighton <lkcl at lkcl.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|enhancement                 |major
           Priority|---                         |High

--- Comment #1 from Luke Kenneth Casson Leighton <lkcl at lkcl.net> ---
yes, that's critically important that no possible indicator of success or
permitting of proceeding to a stage that REQUIRES 100% guaranteed completion.

this is down to the "House Contract Of Sale" protocol, which is:

* Offer
* Exchange
* Complete.

Wishbone is a "TAKE IT OR LEAVE IT" Contract.  you get someone walking
up to you on the street, saying, "buy my goods at reduced price! take it
or leave it!".

Speculative multi-issue execution *cannot* work on top of a take-it-or-leave-it
Contract.  you *have* to have a "conditional offer" phase. ONLY past the
"Exchange" point does it become a 100% cast-iron guaranteed requirement to
"Complete".

addr_ok_o is is part of the "Exchange" process, stating
that there are no objections to proceeding to "Complete"

if addr_ok_o is being raise at the *same time* as an indication that the
"Offer" is *REJECTED* (exc_happened) then that's extremely serious.

-- 
You are receiving this mail because:
You are on the CC list for the bug.