Risc V greatly underperforms

Laurent Desnogues laurent.desnogues at gmail.com
Mon Sep 20 13:34:18 UTC 2021

On Mon, Sep 20, 2021 at 12:07 PM Vincent Lefevre <vincent at vinc17.net> wrote:
> And even the 6502 had an ADC instruction with carry-in and carry-out.
> This is the most logical and intuitive behavior, as from a hardware
> point of view, the carry-in and carry-out are handled *for free*.

This is not completely correct: as soon as you have an out of order
micro architecture with register renaming, you'll have to add hardware
to also rename flags, so it's not 100% free. But I agree that the
price to pay definitely is worth it.


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