Re: [PATCH] LoongArch: Improve memory ops

From: Xi Ruoyao
Date: Mon Apr 10 2023 - 10:38:14 EST


On Mon, 2023-04-10 at 22:19 +0800, Rui Wang wrote:
> On Mon, Apr 10, 2023 at 8:20 PM Xi Ruoyao <xry111@xxxxxxxxxxx> wrote:
> >
> > On Mon, 2023-04-10 at 19:57 +0800, WANG rui wrote:
> > > +       /* align up address */
> > > +       andi    t1, a0, 7
> > > +       sub.d   a0, a0, t1
> >
> > bstrins.d a0, zero, 2, 0
> >
> > Likewise for other aligning operations if the temporary is not used.
>
> I think we're on the same page. I had previously tested this on the
> user-space version[1], but it's not a performance-critical area.

The point is "if you can reduce one instruction and one register usage
with no harm, why not do it?" :)

AFAIK bstrins.d should be available on all 64-bit LoongArch CPUs.


--
Xi Ruoyao <xry111@xxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University