From: Richard Henderson <richard.henderson@linaro.org>
To: "Philippe Mathieu-Daudé" <f4bug@amsat.org>,
"Song Gao" <gaosong@loongson.cn>
Cc: peter.maydell@linaro.org, thuth@redhat.com,
qemu-devel@nongnu.org, maobibo@loongson.cn, laurent@vivier.eu,
alistair.francis@wdc.com, pbonzini@redhat.com
Subject: Re: [PATCH 07/20] target/loongarch: Add fixed point arithmetic instruction translation
Date: Fri, 2 Jul 2021 07:46:29 -0700 [thread overview]
Message-ID: <6079cde9-f274-40e2-77ac-3a942455d58a@linaro.org> (raw)
In-Reply-To: <2912e517-dba0-04f8-80e2-edc0a9b1a27d@amsat.org>
On 7/2/21 1:51 AM, Philippe Mathieu-Daudé wrote:
> static bool trans_mul_d(DisasContext *ctx, int rd, int rj, int rk)
> {
> TCGv t0, t1;
>
> check_loongarch_64(ctx);
>
> if (a->rd == 0) {
> /* Treat as NOP. */
> return true;
> }
>
> t0 = tcg_temp_new();
> t1 = tcg_temp_new();
>
> gen_load_gpr(t0, a->rj);
> gen_load_gpr(t1, a->rk);
Another improvement over mips is possible, while we're at it:
TCGv get_gpr(int regno)
{
if (regno == 0) {
return tcg_constant_tl(0);
} else {
return cpu_gpr[regno];
}
}
t0 = get_gpr(a->rj);
t1 = get_gpr(a->rk);
>
> tcg_gen_mul_i64(cpu_gpr[a->rd], t0, t1);
>
> tcg_temp_free(t0);
> tcg_temp_free(t1);
and now the frees are not necessary.
You do have to be careful that you consume the input before you write back to
cpu_gpr[a->rd]. Previously you had a copy, but now t0 and t1 reference the live register.
And of course you cannot write to either t0 or t1, because one of them might be the
constant 0.
r~
next prev parent reply other threads:[~2021-07-02 14:47 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 12:04 [PATCH 00/20] Add LoongArch linux-user emulation support Song Gao
2021-06-28 12:04 ` [PATCH 01/20] target/loongarch: Add README Song Gao
2021-06-28 18:40 ` Philippe Mathieu-Daudé
2021-06-29 7:33 ` Song Gao
2021-06-29 11:13 ` Alex Bennée
2021-06-30 1:09 ` Song Gao
2021-06-29 11:52 ` Peter Maydell
2021-06-30 1:22 ` Song Gao
2021-06-28 12:04 ` [PATCH 02/20] target/loongarch: Add CSR registers definition Song Gao
2021-06-28 12:04 ` [PATCH 03/20] target/loongarch: Add core definition Song Gao
2021-06-28 18:44 ` Philippe Mathieu-Daudé
2021-06-29 7:39 ` Song Gao
2021-06-28 12:04 ` [PATCH 04/20] target/loongarch: Add interrupt handling support Song Gao
2021-06-28 12:04 ` [PATCH 05/20] target/loongarch: Add memory management support Song Gao
2021-06-28 12:04 ` [PATCH 06/20] target/loongarch: Add main translation routines Song Gao
2021-06-28 18:46 ` Philippe Mathieu-Daudé
2021-06-29 8:50 ` Song Gao
2021-06-29 12:26 ` Alex Bennée
2021-06-30 1:04 ` Song Gao
2021-06-28 12:04 ` [PATCH 07/20] target/loongarch: Add fixed point arithmetic instruction translation Song Gao
2021-07-01 20:31 ` Philippe Mathieu-Daudé
2021-07-02 8:15 ` Song Gao
2021-07-02 8:51 ` Philippe Mathieu-Daudé
2021-07-02 9:16 ` Song Gao
2021-07-02 14:46 ` Richard Henderson [this message]
2021-07-05 0:45 ` Song Gao
2021-06-28 12:04 ` [PATCH 08/20] target/loongarch: Add fixed point shift " Song Gao
2021-06-28 12:04 ` [PATCH 09/20] target/loongarch: Add fixed point bit " Song Gao
2021-06-28 12:04 ` [PATCH 10/20] target/loongarch: Add fixed point load/store " Song Gao
2021-06-28 12:04 ` [PATCH 11/20] target/loongarch: Add fixed point atomic " Song Gao
2021-06-28 12:04 ` [PATCH 12/20] target/loongarch: Add fixed point extra " Song Gao
2021-06-28 12:04 ` [PATCH 13/20] target/loongarch: Add floating point arithmetic " Song Gao
2021-06-28 12:04 ` [PATCH 14/20] target/loongarch: Add floating point comparison " Song Gao
2021-06-28 12:04 ` [PATCH 15/20] target/loongarch: Add floating point conversion " Song Gao
2021-06-28 12:04 ` [PATCH 16/20] target/loongarch: Add floating point move " Song Gao
2021-06-28 12:04 ` [PATCH 17/20] target/loongarch: Add floating point load/store " Song Gao
2021-06-28 12:04 ` [PATCH 18/20] target/loongarch: Add branch " Song Gao
2021-06-28 12:04 ` [PATCH 19/20] target/loongarch: Add disassembler Song Gao
2021-06-28 12:04 ` [PATCH 20/20] target/loongarch: Add linux-user emulation support Song Gao
2021-06-29 13:42 ` Peter Maydell
2021-06-30 1:41 ` maobibo
2021-06-30 9:36 ` Alex Bennée
2021-07-01 1:07 ` maobibo
2021-07-01 6:47 ` Thomas Huth
2021-07-01 7:08 ` maobibo
2021-07-01 10:35 ` Alex Bennée
2021-07-01 10:53 ` Peter Maydell
2021-07-01 12:05 ` maobibo
2021-06-30 1:59 ` Song Gao
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=6079cde9-f274-40e2-77ac-3a942455d58a@linaro.org \
--to=richard.henderson@linaro.org \
--cc=alistair.francis@wdc.com \
--cc=f4bug@amsat.org \
--cc=gaosong@loongson.cn \
--cc=laurent@vivier.eu \
--cc=maobibo@loongson.cn \
--cc=pbonzini@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=thuth@redhat.com \
/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).