From: Richard Henderson <richard.henderson@linaro.org>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Subject: Re: [PATCH 1/4] target/i386: use TSTEQ/TSTNE to test low bits
Date: Wed, 28 Feb 2024 12:28:57 -1000 [thread overview]
Message-ID: <b4d8cebd-6ad3-4a21-9ee0-207b6bd2fde5@linaro.org> (raw)
In-Reply-To: <20240228111151.287738-2-pbonzini@redhat.com>
On 2/28/24 01:11, Paolo Bonzini wrote:
> When testing the sign bit or equality to zero of a partial register, it
> is useful to use a single TSTEQ or TSTNE operation. It can also be used
> to test the parity flag, using bit 0 of the population count.
>
> Do not do this for 32- and 64-bit values however, to avoid
> large immediates.
>
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> ---
> target/i386/tcg/translate.c | 28 ++++++++++++++++++++--------
> target/i386/tcg/emit.c.inc | 5 ++---
> 2 files changed, 22 insertions(+), 11 deletions(-)
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
r~
next prev parent reply other threads:[~2024-02-28 22:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-28 11:11 [PATCH 0/4] target/i386: use TSTEQ/TSTNE in x86 frontend Paolo Bonzini
2024-02-28 11:11 ` [PATCH 1/4] target/i386: use TSTEQ/TSTNE to test low bits Paolo Bonzini
2024-02-28 22:28 ` Richard Henderson [this message]
2024-02-28 11:11 ` [PATCH 2/4] target/i386: use TSTEQ/TSTNE to check flags Paolo Bonzini
2024-02-28 22:34 ` Richard Henderson
2024-02-28 11:11 ` [PATCH 3/4] target/i386: remove mask from CCPrepare Paolo Bonzini
2024-02-28 22:36 ` Richard Henderson
2024-02-28 11:11 ` [PATCH 4/4] tcg/optimize: optimize TSTNE using smask and zmask Paolo Bonzini
2024-02-28 23:10 ` Richard Henderson
2024-02-29 9:35 ` Paolo Bonzini
2024-02-29 17:17 ` Richard Henderson
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