From: Paolo Bonzini <pbonzini@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Subject: Re: [PATCH 1/2] target/i386: fix cmpxchg with 32-bit register destination
Date: Thu, 15 Sep 2022 01:50:25 +0200 [thread overview]
Message-ID: <ed0fa748-5560-9ea5-ea06-bc8213b9942f@redhat.com> (raw)
In-Reply-To: <91fe80d5-724b-6adc-ef74-60655c8a25cf@linaro.org>
On 9/12/22 09:55, Richard Henderson wrote:
>
> * Compute...
>
> Why bother passing NULL, and fixing it up at each use...
>
>> +static void gen_op_mov_reg_v(DisasContext *s, MemOp ot, int reg, TCGv
>> t0)
>> +{
>> + gen_op_deposit_reg_v(s, ot, reg, NULL, t0);
>> }
>
> ... when you can just as easily pass in the register here?
Because dest can be fixed up to either cpu_regs[reg - 4] for high-byte
registers, or cpu_regs[reg] for everything else.
> We have an outstanding bug report that suggests that the move to eax must use the deposit in both cases:
>
> https://gitlab.com/qemu-project/qemu/-/issues/508
Ok, so that's two bugs. But both of them can indeed be fixed with
gen_op_deposit_reg_v.
Paolo
next prev parent reply other threads:[~2022-09-14 23:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-11 22:26 [PATCH 0/2] target/i386: two fixes for cmpxchg Paolo Bonzini
2022-09-11 22:26 ` [PATCH 1/2] target/i386: fix cmpxchg with 32-bit register destination Paolo Bonzini
2022-09-12 7:55 ` Richard Henderson
2022-09-14 23:50 ` Paolo Bonzini [this message]
2022-09-11 22:26 ` [PATCH 2/2] target/i386: cmpxchg only overwrites ZF Paolo Bonzini
2022-09-12 7:58 ` Richard Henderson
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=ed0fa748-5560-9ea5-ea06-bc8213b9942f@redhat.com \
--to=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=richard.henderson@linaro.org \
/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 NNTP newsgroup(s).