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[187.189.51.143]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-3f5d4e12e4fsm1946137fac.2.2025.12.11.08.15.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 11 Dec 2025 08:15:02 -0800 (PST) Message-ID: <9b0836f8-6937-427e-b6d2-efe83dd23597@linaro.org> Date: Thu, 11 Dec 2025 10:15:00 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 08/18] target/i386/tcg: simplify effective address calculation To: Paolo Bonzini , qemu-devel@nongnu.org References: <20251210131653.852163-1-pbonzini@redhat.com> <20251210131653.852163-9-pbonzini@redhat.com> From: Richard Henderson Content-Language: en-US In-Reply-To: <20251210131653.852163-9-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2001:4860:4864:20::29; envelope-from=richard.henderson@linaro.org; helo=mail-oa1-x29.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 12/10/25 07:16, Paolo Bonzini wrote: > Split gen_lea_v_seg_dest into three simple phases (extend from > 16 bits, add, final extend), with optimization for known-zero bases > to avoid back-to-back extensions. > > Signed-off-by: Paolo Bonzini > --- > target/i386/tcg/translate.c | 64 ++++++++++++------------------------- > 1 file changed, 20 insertions(+), 44 deletions(-) > > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c > index 0cb87d02012..2ab3c2ac663 100644 > --- a/target/i386/tcg/translate.c > +++ b/target/i386/tcg/translate.c > @@ -627,54 +627,30 @@ static TCGv eip_cur_tl(DisasContext *s) > static void gen_lea_v_seg_dest(DisasContext *s, MemOp aflag, TCGv dest, TCGv a0, > int def_seg, int ovr_seg) > { > - switch (aflag) { > -#ifdef TARGET_X86_64 > - case MO_64: > - if (ovr_seg < 0) { > - tcg_gen_mov_tl(dest, a0); > - return; > + int easize; > + bool has_base; > + > + if (ovr_seg < 0) { > + ovr_seg = def_seg; > + } > + > + has_base = ovr_seg >= 0 && (ADDSEG(s) || ovr_seg >= R_FS); I guess def_seg is -1 for LEA, so ovr_seg can still be -1. I wonder if it would be clearer to avoid this duplication of segment earlier in decode? Anyway, for here, maybe clearer as has_base = ovr_seg >= R_FS || (ovr_seg >= 0 && ADDSEG(s)); even though the end result is the same. Nice cleanup. Reviewed-by: Richard Henderson r~