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

Luke Kenneth Casson Leighton lkcl at lkcl.net
Thu Apr 9 02:21:54 BST 2020


On Thursday, April 9, 2020, <whygee at f-cpu.org> wrote:

>
> Could you please elaborate on your system ?
> Is there some sort of buffer to store the immediates
> while waiting for other operands to be ready ?


it's literally as described in Mitch's book chapters.  minor alterations
are documented here
https://libre-soc.org/3d_gpu/architecture/6600scoreboard/

you can see in the CompUnit, a latch for immediates and a latch for reg
operands.

one bit says "latch the immediate instead of operand2 as the 2nd input to
the ALU".

very simple.

l.



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