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From: Huacai Chen <chenhuacai@kernel.org>
To: Xi Ruoyao <xry111@xry111.site>
Cc: Huacai Chen <chenhuacai@loongson.cn>,
	loongarch@lists.linux.dev, Xuefeng Li <lixuefeng@loongson.cn>,
	Tiezhu Yang <yangtiezhu@loongson.cn>, Guo Ren <guoren@kernel.org>,
	Xuerui Wang <kernel@xen0n.name>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] LoongArch: Add unaligned access support
Date: Mon, 17 Oct 2022 08:16:53 +0800	[thread overview]
Message-ID: <CAAhV-H4vGt4MTXCyiSnn7cQFrxR-amLC4nKe7-EcLyT8G-Ciqg@mail.gmail.com> (raw)
In-Reply-To: <c1b674a37a1a04f9c84df1e9a227db68bf78e922.camel@xry111.site>

Hi, Ruoyao,

On Sun, Oct 16, 2022 at 11:05 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> On Sun, 2022-10-16 at 21:34 +0800, Huacai Chen wrote:
>
> > Loongson-2 series (Loongson-2K500, Loongson-2K1000)
>
> "2K1000LA"? "2K1000" is puzzling because of a name conflict with the
> MIPS-based model.
Technically this is correct, both MIPS-based and LoongArch-based
Loongson-2K1000 have no hardware support.

>
> /* snip */
>
> > +static inline unsigned long read_fpr(unsigned int fd)
> > +{
> > +#define READ_FPR(fd, __value)          \
> > +{                                      \
>
> Unnecessary curly brace pair.
OK,thanks.

>
> > +       __asm__ __volatile__(           \
> > +       "movfr2gr.d\t%0, $f%1\n\t"      \
> > +       : "=r"(__value) : "i"(fd));     \
> > +}
>
> I'm not sure if this is a correct use of "i" constraint.  Maybe we
> should just concatenate the string?
OK, thanks.

Huacai
>
> "movfr2gr.d\t%0, $f" #fd "\n\t"
>
> > +
> > +       unsigned long __value;
> > +
> > +       switch (fd) {
>
> I don't like this "very long" switch statement, but it seems we have no
> way to make it better...
>
> > +       case 0:
> > +               READ_FPR(0, __value);
> > +               break;
> > +       case 1:
> > +               READ_FPR(1, __value);
> > +               break;
> > +       case 2:
> > +               READ_FPR(2, __value);
> > +               break;
>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University

  reply	other threads:[~2022-10-17  0:17 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-16 13:34 [PATCH] LoongArch: Add unaligned access support Huacai Chen
2022-10-16 15:04 ` Xi Ruoyao
2022-10-17  0:16   ` Huacai Chen [this message]
2022-10-17  5:49     ` WANG Xuerui
2022-10-17  7:12 ` Arnd Bergmann
2022-10-17  7:31   ` Huacai Chen
2022-10-17  7:38     ` Arnd Bergmann
2022-10-17  8:05       ` WANG Xuerui
2022-10-17  8:22         ` Arnd Bergmann
2022-10-17  8:13       ` Xi Ruoyao

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