Re: [PATCH 08/17] alpha: Implement xor_unlock_is_negative_byte

Linus Torvalds
2023-09-16T02:16:03Z

On Fri, 15 Sept 2023 at 19:01, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> No, I think "mov src,dst" is just a pseudo-op for "or src,src,dst",
> there's no actual "mov" instruction, iirc.

Bah. I looked it up. It's actually supposed to be "BIS r31,src,dst".

Where "BIS" is indeed what most sane people call just "or". I think
it's "BIt Set", but the assembler will accept the normal "or" mnemonic
too.

There's BIC ("BIt Clear") too. Also known as "and with complement".

I assume it comes from some VAX background. Or maybe it's just a NIH
thing and alpha wanted to be "special".

Linus