[libre-riscv-dev] morphing 6600 code to use power decoder

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon Apr 13 19:27:41 BST 2020

On Mon, Apr 13, 2020 at 6:46 PM <whygee at f-cpu.org> wrote:
> On 2020-04-13 16:16, Luke Kenneth Casson Leighton wrote:
> > https://groups.google.com/forum/#!topic/comp.arch/qeMsE7UxvlI
> > https://libre-soc.org/3d_gpu/architecture/6600scoreboard/
> > https://www.youtube.com/watch?v=ohHbWRLDCfs
> >
> > this is quite a significant core change to the 6600 scoreboard engine,
> > so i'm soliciting outside help in reviewing it.  ironically (and very
> > much to the point) i realised an error towards the end of the
> > description.
> I couldn't be sure to understand all the subtleties.

CompUnits are a forward-progress looped Finite-State-Machine.  Issue,
Read, Write, Issue, Read, Write.  that's now Issue, {Read1/2/3},
{Write1/2}, Issue {Read1/2/3}, {Write1/2} repeat repeat.

Dependency Matrices: Reads stop Writes, Writes stop Reads.  now there
are multiple read-regs, any one of those multiple Read-Regs must stop
Writes, any one of those multiple Write-Regs must stop Reads.

> However remove the comment from "Tom"/Temar
> who is a click-harvesting bot on youtube.


> Anyway : impressive work !

appreciated.  now i have to implement it.  and modify all the
dependent code that uses it.  sigh.  it'll be about a month's work.


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