[Libre-soc-dev] NLnet Ongoing Grant

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sun Sep 3 01:28:18 BST 2023


i cannot entirely reveal why due to commercial confidentiality,
but after some thought and Jacob's meticulous detailed estimates
i think we need to pull the FP Unit entirely from the
Ongoing Grant bug #961, park it for "Future" (given that for
proper justice Jacob's estimates come out at EUR 24,000
and that's not even including TestIssuer integration)
and replace it with the following chain-dependent list of
tasks:

* removing use of PO1 and replacing with PO9
* creating EXT200-263 under PO9
* moving all LD/ST-post-update to EXT200-263, with their exact
 respective *pre-update* EXT000-063 encodings
 (example: lhz is EXT040, therefore lhzp *is* EXT240, no
  arguing, no question: it just *is*)
* freeing up the LDST_IMM SVP64 "post-update" bit and allocating
 it instead to Vector-Immediate (with elwidths on VIs)
* using the reserved Normal/Arithmetic mode also for VI
* finishing LDST-EXTRA-322

this is a lot of work, definitely equal to the current EUR 8,000
available budget, especially given that it involves:

* specification writing and checking
* insndb updating (two ways: PO9 itself *and* the new EXT2xx
* a new PowerDecoder (for EXT2xx)
* test_caller* unit tests
* writing the LD/ST-post-update mdwn files (Nicholas, new member)
* ISACaller updates
* binutils updates (to SVP64 as well as a new EXT2xx area)

there is also the strong possibility of Dmitry managing to make
a Visitor-version nmigen Decoder, 100% compatible with the
existing PowerDecoder (still using PowerOp Dmitry, that's
very important) which is a task under cavatools (approved MoU),
which would make creating EXT2xx a LOT easier, but we shall
see how it goes.



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