From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9C1BC433EF for ; Mon, 15 Nov 2021 04:01:01 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 06A2F630EC for ; Mon, 15 Nov 2021 04:01:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 06A2F630EC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:57740 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mmTAx-00008G-ST for qemu-devel@archiver.kernel.org; Sun, 14 Nov 2021 23:00:59 -0500 Received: from eggs.gnu.org ([209.51.188.92]:33496) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mmT9y-0007sF-VA for qemu-devel@nongnu.org; Sun, 14 Nov 2021 22:59:58 -0500 Received: from mail.loongson.cn ([114.242.206.163]:43842 helo=loongson.cn) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mmT9t-00024R-Dg for qemu-devel@nongnu.org; Sun, 14 Nov 2021 22:59:58 -0500 Received: from [10.20.42.193] (unknown [10.20.42.193]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxmuQS25FhbQgAAA--.281S3; Mon, 15 Nov 2021 11:59:14 +0800 (CST) Subject: Re: [PATCH v10 04/26] target/loongarch: Add fixed point arithmetic instruction translation To: Richard Henderson , qemu-devel@nongnu.org References: <1636700049-24381-1-git-send-email-gaosong@loongson.cn> <1636700049-24381-5-git-send-email-gaosong@loongson.cn> <7e6e5c26-2c1a-e4b5-a724-c2db33a36180@linaro.org> From: gaosong Message-ID: <5c3c3107-da7f-7e13-189e-866c7ff1acde@loongson.cn> Date: Mon, 15 Nov 2021 11:59:14 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <7e6e5c26-2c1a-e4b5-a724-c2db33a36180@linaro.org> Content-Type: multipart/alternative; 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envelope-from=gaosong@loongson.cn; helo=loongson.cn X-Spam_score_int: -52 X-Spam_score: -5.3 X-Spam_bar: ----- X-Spam_report: (-5.3 / 5.0 requ) BAYES_00=-1.9, HTML_MESSAGE=0.001, NICE_REPLY_A=-3.402, SPF_HELO_PASS=-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: , Cc: Xiaojuan Yang , laurent@vivier.eu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is a multi-part message in MIME format. --------------36DBB13C8EDA14317D441ED6 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Hi Richard, On 2021/11/12 下午10:05, Richard Henderson wrote: > On 11/12/21 7:53 AM, Song Gao wrote: >> +# >> +# Fields >> +# >> +%rd      0:5 >> +%rj      5:5 >> +%rk      10:5 >> +%sa2     15:2 >> +%si12    10:s12 >> +%ui12    10:12 >> +%si16    10:s16 >> +%si20    5:s20 > > You should only create separate field definitions like this when they > are complex: e.g. the logical field is disjoint or there's a need for > !function. > >> + >> +# >> +# Argument sets >> +# >> +&fmt_rdrjrk         rd rj rk >> +&fmt_rdrjsi12       rd rj si12 >> +&fmt_rdrjrksa2      rd rj rk sa2 >> +&fmt_rdrjsi16       rd rj si16 >> +&fmt_rdrjui12       rd rj ui12 >> +&fmt_rdsi20         rd si20 > > Some of these should be combined.  The width of the immediate is a > detail of the format, not the decoded argument set.  Thus you should have > > &fmt_rdimm     rd imm > &fmt_rdrjimm   rd rj imm > &fmt_rdrjrk    rd rj rk > &fmt_rdrjrksa  rd rj rk sa > 'The width of the immediate is a detail of the format' means: &fmt_rdrjimm rd rj imm @fmt_rdrjimm .... ...... imm:12 rj:5 rd:5 &fmt_rdrjimm @fmt_rdrjimm14 .... .... imm:14 rj:5 rd:5 &fmt_rdrjimm @fmt_rdrjimm16 .... .. imm:16 rj:5 rd:5 &fmt_rdrjimm and we print in the disassembly, liks this output_rdrjimm(DisasContext *ctx, arg_fmt_rdrjimm * a, const char *mnemonic) { output(ctx, mnemonic, "%s, %s, 0x%x", regnames[a->rd], regnames[a->rj], a->imm); } is that right? >> +alsl_w           0000 00000000 010 .. ..... ..... .....   >> @fmt_rdrjrksa2 >> +alsl_wu          0000 00000000 011 .. ..... ..... .....   >> @fmt_rdrjrksa2 >> +alsl_d           0000 00000010 110 .. ..... ..... .....   >> @fmt_rdrjrksa2 > > The encoding of these insns is that the shift is sa+1. > > While you compensate for this in gen_alsl_*, we print the "wrong" > number in the disassembly.  I think it would be better to do > > %sa2p1     15:2 !function=plus_1 > @fmt_rdrjrksa2p1  .... ........ ... .. rk:5 rj:5 rd:5 \ >                   &fmt_rdrjrksa sa=%sa2p1 > 1. We print sa in disassembly output_rdrjrksa(DisasContext *ctx, arg_fmt_rdrjsa* a, const char *memonic) { output(ctx, memonic, "%s, %s, %s, 0x0x", regnames[a->rd], regnames[a->rj], a->sa) } 2. We use sa on gen_alsl_* not (sa2+1). 3 bytepick_w use the same print functions. but the Field/Argurment/Format is %sa2 15:2 &fmt_rdrjrksa rd rj sa @fmt_rdrjrk sa2 .... ........ ... sa:2 rk:5 rj:5 rd:5 &fmt_rdrjrksa Is my understanding right? Thanks. Song Gao --------------36DBB13C8EDA14317D441ED6 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit

Hi Richard,

On 2021/11/12 下午10:05, Richard Henderson wrote:
On 11/12/21 7:53 AM, Song Gao wrote:
+#
+# Fields
+#
+%rd      0:5
+%rj      5:5
+%rk      10:5
+%sa2     15:2
+%si12    10:s12
+%ui12    10:12
+%si16    10:s16
+%si20    5:s20

You should only create separate field definitions like this when they are complex: e.g. the logical field is disjoint or there's a need for !function.

+
+#
+# Argument sets
+#
+&fmt_rdrjrk         rd rj rk
+&fmt_rdrjsi12       rd rj si12
+&fmt_rdrjrksa2      rd rj rk sa2
+&fmt_rdrjsi16       rd rj si16
+&fmt_rdrjui12       rd rj ui12
+&fmt_rdsi20         rd si20

Some of these should be combined.  The width of the immediate is a detail of the format, not the decoded argument set.  Thus you should have

&fmt_rdimm     rd imm
&fmt_rdrjimm   rd rj imm
&fmt_rdrjrk    rd rj rk
&fmt_rdrjrksa  rd rj rk sa 

'The width of the immediate is a detail of the format'  means:

&fmt_rdrjimm         rd  rj imm 

@fmt_rdrjimm         .... ...... imm:12  rj:5 rd:5     &fmt_rdrjimm
@fmt_rdrjimm14         .... .... imm:14  rj:5 rd:5     &fmt_rdrjimm 
@fmt_rdrjimm16           .... .. imm:16  rj:5 rd:5     &fmt_rdrjimm

and we print in the disassembly, liks this 

output_rdrjimm(DisasContext *ctx, arg_fmt_rdrjimm * a,  const char *mnemonic)
{
    output(ctx, mnemonic, "%s, %s, 0x%x", regnames[a->rd], regnames[a->rj], a->imm);
}

is that right?
+alsl_w           0000 00000000 010 .. ..... ..... .....   @fmt_rdrjrksa2
+alsl_wu          0000 00000000 011 .. ..... ..... .....   @fmt_rdrjrksa2
+alsl_d           0000 00000010 110 .. ..... ..... .....   @fmt_rdrjrksa2

The encoding of these insns is that the shift is sa+1.

While you compensate for this in gen_alsl_*, we print the "wrong" number in the disassembly.  I think it would be better to do

%sa2p1     15:2 !function=plus_1
@fmt_rdrjrksa2p1  .... ........ ... .. rk:5 rj:5 rd:5 \
                  &fmt_rdrjrksa sa=%sa2p1 

1. We print sa in disassembly 
output_rdrjrksa(DisasContext *ctx, arg_fmt_rdrjsa* a, const char *memonic)
{
    output(ctx, memonic, "%s, %s, %s, 0x0x", regnames[a->rd], regnames[a->rj], a->sa)
}

2. We use sa on gen_alsl_*  not  (sa2+1). 

3 bytepick_w use the same print functions. but the Field/Argurment/Format is 
%sa2      15:2
&fmt_rdrjrksa   rd rj sa
@fmt_rdrjrk sa2  .... ........ ...  sa:2  rk:5 rj:5 rd:5  &fmt_rdrjrksa

Is my understanding right?

Thanks.
Song Gao
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