Mill Computing, Inc. Forums Announcements Events Ivan Godard and Mill at the 2015 European LLVM Conference Reply To: Ivan Godard and Mill at the 2015 European LLVM Conference

LarryP
Participant
Post count: 78

@david, re 68-bit literals,

Quite possibly. If you look at the flow-side decoding, outlined in:
http://millcomputing.com/wiki/Decode#Flow_Stream, you’ll see that it’s very different from the exu side encode/decode that Ivan described in the encoding talk.

Flow-side has both Manifests (up to 32 bits) and extensions (up to 3x morsel width, member dependent, 5 bits on gold), which suggests that each const operation could drop a 32 bit (or on gold potentially 32 + 3*5 = 57 bit) constant. Mill members with enough flow-side slots can thus drop a whole lot of bits of constant per instruction.

What I’m less clear on — and hope to learn — is how the results of multiple const operations can be combined into a 64-bit (or evidently slightly longer) constant, not only in the same instruction, but in time to be used in opPhase, for the (ganged subtract/less-than) comparison in Ivan’s single-instruction example above. Ivan’s rather busy today, I’d imagine! 😉
But maybe one of the other Millcomputing gurus will answer in the near future.

  • This reply was modified 7 years, 5 months ago by  LarryP.