From: Jan Beulich <jbeulich@suse.com>
To: jacob navia <jacob@jacob.remcomp.fr>
Cc: Peter Bergner <bergner@linux.ibm.com>,
binutils@sourceware.org, Andrew Waterman <andrew@sifive.com>
Subject: Re: Defined illegal instruction
Date: Mon, 12 Feb 2024 08:29:14 +0100 [thread overview]
Message-ID: <924c9ff6-4583-40b7-8099-4c48baf4dbaf@suse.com> (raw)
In-Reply-To: <80629157-361A-457F-81E1-21D2D23DD99F@jacob.remcomp.fr>
On 10.02.2024 13:56, jacob navia wrote:
> OK. So now we have:
>
> unimp and
> c.unimp
>
> Both generate 16 bit zeroes if the C extension is present.
>
> If the C extension is not present,
> unimp generates
>
> csrw cycle, x0
>
> If we want to generate the defined unimplemented instruction in 32 bis we write
>
> .long 0
>
> As in the power PC.
Except that on RISC-V (and other architectures separating code from data
by special labels, like Arm) you want to use .insn. Iirc this also ensures
debug line info would be properly emitted, if enabled.
Jan
next prev parent reply other threads:[~2024-02-12 7:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-09 17:03 jacob navia
2024-02-09 17:21 ` Peter Bergner
2024-02-10 0:03 ` Andrew Waterman
2024-02-10 12:56 ` jacob navia
2024-02-11 0:50 ` Andrew Waterman
2024-02-12 7:29 ` Jan Beulich [this message]
[not found] ` <C47C292B-6017-4D1C-BEEC-E4D9D88BBD8E@jacob.remcomp.fr>
2024-02-13 7:20 ` Jan Beulich
2024-02-13 9:05 ` jacob navia
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=924c9ff6-4583-40b7-8099-4c48baf4dbaf@suse.com \
--to=jbeulich@suse.com \
--cc=andrew@sifive.com \
--cc=bergner@linux.ibm.com \
--cc=binutils@sourceware.org \
--cc=jacob@jacob.remcomp.fr \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).