From: Christoph Hellwig <hch@infradead.org>
To: Jim Wilson <jimw@sifive.com>
Cc: Eric Lin <tesheng@andestech.com>,
dslin1010@gmail.com, alankao@andestech.com,
Palmer Dabbelt <palmer@sifive.com>,
rick@andestech.com, kclin@andestech.com,
Paul Walmsley <paul.walmsley@sifive.com>,
linux-riscv@lists.infradead.org
Subject: Re: About __udivdi3
Date: Tue, 6 Aug 2019 01:31:35 -0700 [thread overview]
Message-ID: <20190806083135.GA12410@infradead.org> (raw)
In-Reply-To: <CAFyWVaYd1vGFLJj6hh+a5Ufubh3tvwER+-ShQXA3faEJbEFe3A@mail.gmail.com>
On Mon, Aug 05, 2019 at 08:01:27PM -0700, Jim Wilson wrote:
> On Mon, Aug 5, 2019 at 7:13 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
> > > > It seems __udivdi3 only supports 64-bit platform.
> > > > Do you have any comments? Thanks.
> >
> > It sounds like you're describing a potential issue with gcc, rather than
> > the kernel. If that's so, then the gcc mailing list(s) would be a better
> > place to discuss this: https://gcc.gnu.org/lists.html
>
> The kernel doesn't link with libgcc.a. It has its own copy of udivdi3
> when needed.
Linus still maintains his stance to not support 64 by 64-bit divisions
on 32-bit platforms, and thus Linux does not support it. You can do
64 by 32-bit divisions using the awkward do_div macros, but that's it.
This is supposed to apply to all 32-bit platforms, not just RISC-V.
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next prev parent reply other threads:[~2019-08-06 8:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190805055844.GE4292@andestech.com>
2019-08-06 1:37 ` About __udivdi3 Eric Lin
2019-08-06 2:13 ` Paul Walmsley
2019-08-06 2:59 ` Eric Lin
2019-08-06 3:01 ` Jim Wilson
2019-08-06 3:45 ` Nicolas Pitre
2019-08-06 8:31 ` Christoph Hellwig [this message]
2019-08-06 15:08 ` Palmer Dabbelt
2019-08-06 17:53 ` Paul Walmsley
2019-08-06 17:59 ` Palmer Dabbelt
2019-08-06 18:37 ` Nicolas Pitre
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