From: Jan Beulich <jbeulich@suse.com>
To: Nelson Chu <nelson@rivosinc.com>
Cc: Binutils <binutils@sourceware.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Andrew Waterman <andrew@sifive.com>,
Jim Wilson <jim.wilson.gcc@gmail.com>,
Kito Cheng <kito.cheng@sifive.com>
Subject: Re: [PATCH] RISC-V: don't disassemble unrecognized insns as .byte
Date: Mon, 30 Jan 2023 08:51:08 +0100 [thread overview]
Message-ID: <4fd5ad07-919e-1502-8688-9ade69af2a64@suse.com> (raw)
In-Reply-To: <CAPpQWtBF+ND85kZ-pZRiYgrnJ95s1gXdgii-gzwsE20o8o_1nA@mail.gmail.com>
On 30.01.2023 02:40, Nelson Chu wrote:
> On Fri, Jan 27, 2023 at 9:14 PM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> Insn width granularity being 16 bits, produce 16 bits of data per output
>> element for the non-special-cased insn widths. Besides being slightly
>> more natural (in particular having the first element carry everything
>> that's needed for determining insn length), this is also slightly more
>> compact.
>
> Sounds reasonable and good, so please commit, thanks.
Given ...
>> ---
>> I think output would be even more neat if .<N>byte were suppressed when
>> generic code already prints the raw insn (or maybe something like
>> <unknown> was printed instead).
>>
>> As to the special case code for 2-, 4-, and 8-byte insns: Any thoughts
>> towards zero-padding the numbers there as well? That would make yet more
>> noticable what the insn width is; in particular - see e.g. ".8byte 0x3f"
>> in full disassembly of the testcases modified here - it would avoid the
>> value looking like it was for a more narrow one.
>>
>> Taking it yet one step further - how about printing unknown insns as
>> ".insn ...", matching what gas would consume?
>
> I don't remember how long ago, Kito did discuss this idea with me, but
> since we haven't supported mapping symbols at that time, it's been
> forgotten until this patch. Anyway, I vote to dump the unrecognized
> instructions into .insn directives, so if there is no objection,
> please go ahead.
>
> Also cc Kito, he should have almost forgotten about this :-)
both of you think this is a good direction to follow, I won't even bother
committing the patch here, but make one to switch to emitting .insn right
away. With some luck later this week ...
Jan
prev parent reply other threads:[~2023-01-30 7:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-27 13:14 Jan Beulich
2023-01-30 1:40 ` Nelson Chu
2023-01-30 1:51 ` Maciej W. Rozycki
2023-01-30 3:03 ` Nelson Chu
2023-01-30 3:33 ` Maciej W. Rozycki
2023-01-31 1:51 ` Nelson Chu
2023-01-30 2:07 ` Kito Cheng
2023-01-30 7:51 ` Jan Beulich [this message]
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