From nobody Wed May 7 00:55:49 2025
Delivered-To: importer@patchew.org
Authentication-Results: mx.zohomail.com;
dkim=pass;
spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as
permitted sender)
smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org;
dmarc=pass(p=none dis=none) header.from=linaro.org
ARC-Seal: i=1; a=rsa-sha256; t=1625231244; cv=none;
d=zohomail.com; s=zohoarc;
b=JPv1Aka2d38GfTetyOfbxy6CdzHPr74QzjvgZ0NsLrAI7VQpixpBawl/OKBEOdu/3IioUFmL8ip70MYlnAk2lFjIRLgP52AeM4x/jCfAol1L5YE0vGkMraIS+7E9Kzb5QQBBMC4hJxDgM85gfnez80D+8pdaMrigcADGev7E6xA=
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com;
s=zohoarc;
t=1625231244;
h=Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To;
bh=UQPi/kUp+uvcW0U/4IEHWBFHwSt442+bKNNaejrY1JA=;
b=STVo8Iw4yHWN5cecPxySPqqmjZwMKbalFG1PepmM1qzmxF079CAGNPJcCbXWa3eBpSffg/oZDSckyqbOWTC3CHTMMi9vMEGOKGCw81aakbvGGIuMsYNBQHWmr68VEAUp8H4Kt70mvQbE+im0tBjN3GRrYj2d+0a65XCPbQZcIDY=
ARC-Authentication-Results: i=1; mx.zohomail.com;
dkim=pass;
spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as
permitted sender)
smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org;
dmarc=pass header.from=<peter.maydell@linaro.org> (p=none dis=none)
Return-Path: <qemu-devel-bounces+importer=patchew.org@nongnu.org>
Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by
mx.zohomail.com
with SMTPS id 1625231244478524.905051062473;
Fri, 2 Jul 2021 06:07:24 -0700 (PDT)
Received: from localhost ([::1]:34474 helo=lists1p.gnu.org)
by lists.gnu.org with esmtp (Exim 4.90_1)
(envelope-from <qemu-devel-bounces+importer=patchew.org@nongnu.org>)
id 1lzIt9-0005B1-GG
for importer@patchew.org; Fri, 02 Jul 2021 09:07:23 -0400
Received: from eggs.gnu.org ([2001:470:142:3::10]:33164)
by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)
(Exim 4.90_1) (envelope-from <peter.maydell@linaro.org>)
id 1lzIm7-0007cS-Jn
for qemu-devel@nongnu.org; Fri, 02 Jul 2021 09:00:07 -0400
Received: from mail-wm1-x32a.google.com ([2a00:1450:4864:20::32a]:52065)
by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)
(Exim 4.90_1) (envelope-from <peter.maydell@linaro.org>)
id 1lzIm3-0007fC-AM
for qemu-devel@nongnu.org; Fri, 02 Jul 2021 09:00:07 -0400
Received: by mail-wm1-x32a.google.com with SMTP id r3so6635255wmq.1
for <qemu-devel@nongnu.org>; Fri, 02 Jul 2021 06:00:02 -0700 (PDT)
Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148])
by smtp.gmail.com with ESMTPSA id s3sm3333351wro.30.2021.07.02.06.00.01
for <qemu-devel@nongnu.org>
(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
Fri, 02 Jul 2021 06:00:01 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google;
h=from:to:subject:date:message-id:in-reply-to:references:mime-version
:content-transfer-encoding;
bh=UQPi/kUp+uvcW0U/4IEHWBFHwSt442+bKNNaejrY1JA=;
b=qhwi38u3kF8PAc2ahkAFJB8e10w2GHECZZO3vrpxGpmqcRIGDGtV49bcnzP6Cp5WY9
n38azQX4zd5mDHRCci3EKNiV24Gi9jhNDf6LugRsdBh5DyHpvGSa6VKWxih9YB+LX9Pd
/BxoOJUsBQPboOxjrKJRUAeTb9p8ialijUg7aQr5eD/3vZUstXfPra3YSfUldaj4Hkeg
JXNkNyiPzo1/kcxhDMN9iceRGz54pRDiREZi6rZggSGhjsM/4Q73n0q7jWX8r1svXvL6
cC0OwVy+j7eYrN+sBTyA6wSlbjR8f9atCJgx/Xl+TkGUB0XW16fR9/D9m1wlwxZmOynR
pcOg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20161025;
h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to
:references:mime-version:content-transfer-encoding;
bh=UQPi/kUp+uvcW0U/4IEHWBFHwSt442+bKNNaejrY1JA=;
b=n62+sdVBg1NcB8esgqw20TDlDYtTSSvieSez2nCFx8T2p5G9QUBSFiUMqszlSv90z+
blMWdGcdDuuo/EIQ+zfZ5+xaOrGqU/DxFZZecX8wXhdvrhH6fefKqJkzNIxDuNAFWeOz
h0dE+4uLjdm640d3t0bdhlKdZ+fuJxjF386fzuas46Qy/91uGkVBbEsNG0rZ3IAEWcBO
b+AYmWsJm0EysOjsDurnA0nFenKHvQnLTKWbYed+GYwwH8u4OA+Xfz2yrRazTKOEeFOX
GNRvxFeVbU4Zh9kpZdyN74hv41yuc75uAFS6/fEq8y8JaQ9Rqcds4TIxB66xJMAVnGDd
J4bA==
X-Gm-Message-State: AOAM531FwoMLsbTLBYROL2CkjxxvTkfCPwaFIo/6ILdturKzgcJ4rW8C
gInPQuqfarry/YBT9aHoDbK5zMmZUCXDIzHS
X-Google-Smtp-Source:
ABdhPJwaExxHujyLhRLozI7jOLR5NqyMCDGJEIOmCosW0QKuiDQnt0War2i6Q+Hj73OvpS1rxjTXyw==
X-Received: by 2002:a1c:4b10:: with SMTP id y16mr5251436wma.121.1625230801845;
Fri, 02 Jul 2021 06:00:01 -0700 (PDT)
From: Peter Maydell <peter.maydell@linaro.org>
To: qemu-devel@nongnu.org
Subject: [PULL 08/24] target/arm: Fix bugs in MVE VRMLALDAVH, VRMLSLDAVH
Date: Fri, 2 Jul 2021 13:59:38 +0100
Message-Id: <20210702125954.13247-9-peter.maydell@linaro.org>
X-Mailer: git-send-email 2.20.1
In-Reply-To: <20210702125954.13247-1-peter.maydell@linaro.org>
References: <20210702125954.13247-1-peter.maydell@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17
as permitted sender) client-ip=209.51.188.17;
envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org;
helo=lists.gnu.org;
Received-SPF: pass client-ip=2a00:1450:4864:20::32a;
envelope-from=peter.maydell@linaro.org; helo=mail-wm1-x32a.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: 2.1.23
Precedence: list
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <https://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org
Sender: "Qemu-devel" <qemu-devel-bounces+importer=patchew.org@nongnu.org>
X-ZohoMail-DKIM: pass (identity @linaro.org)
X-ZM-MESSAGEID: 1625231245289100001
Content-Type: text/plain; charset="utf-8"
The initial implementation of the MVE VRMLALDAVH and VRMLSLDAVH
insns had some bugs:
* the 32x32 multiply of elements was being done as 32x32->32,
not 32x32->64
* we were incorrectly maintaining the accumulator in its full
72-bit form across all 4 beats of the insn; in the pseudocode
it is squashed back into the 64 bits of the RdaHi:RdaLo
registers after each beat
In particular, fixing the second of these allows us to recast
the implementation to avoid 128-bit arithmetic entirely.
Since the element size here is always 4, we can also drop the
parameterization of ESIZE to make the code a little more readable.
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210628135835.6690-3-peter.maydell@linaro.org
---
target/arm/mve_helper.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)
diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
index 05552ce7eee..85a552fe070 100644
--- a/target/arm/mve_helper.c
+++ b/target/arm/mve_helper.c
@@ -18,7 +18,6 @@
*/
=20
#include "qemu/osdep.h"
-#include "qemu/int128.h"
#include "cpu.h"
#include "internals.h"
#include "vec_internal.h"
@@ -1100,40 +1099,45 @@ DO_LDAV(vmlsldavsw, 4, int32_t, false, +=3D, -=3D)
DO_LDAV(vmlsldavxsw, 4, int32_t, true, +=3D, -=3D)
=20
/*
- * Rounding multiply add long dual accumulate high: we must keep
- * a 72-bit internal accumulator value and return the top 64 bits.
+ * Rounding multiply add long dual accumulate high. In the pseudocode
+ * this is implemented with a 72-bit internal accumulator value of which
+ * the top 64 bits are returned. We optimize this to avoid having to
+ * use 128-bit arithmetic -- we can do this because the 74-bit accumulator
+ * is squashed back into 64-bits after each beat.
*/
-#define DO_LDAVH(OP, ESIZE, TYPE, XCHG, EVENACC, ODDACC, TO128) \
+#define DO_LDAVH(OP, TYPE, LTYPE, XCHG, SUB) \
uint64_t HELPER(glue(mve_, OP))(CPUARMState *env, void *vn, \
void *vm, uint64_t a) \
{ \
uint16_t mask =3D mve_element_mask(env); \
unsigned e; \
TYPE *n =3D vn, *m =3D vm; =
\
- Int128 acc =3D int128_lshift(TO128(a), 8); \
- for (e =3D 0; e < 16 / ESIZE; e++, mask >>=3D ESIZE) { =
\
+ for (e =3D 0; e < 16 / 4; e++, mask >>=3D 4) { =
\
if (mask & 1) { \
+ LTYPE mul; \
if (e & 1) { \
- acc =3D ODDACC(acc, TO128(n[H##ESIZE(e - 1 * XCHG)] * \
- m[H##ESIZE(e)])); \
+ mul =3D (LTYPE)n[H4(e - 1 * XCHG)] * m[H4(e)]; \
+ if (SUB) { \
+ mul =3D -mul; \
+ } \
} else { \
- acc =3D EVENACC(acc, TO128(n[H##ESIZE(e + 1 * XCHG)] *=
\
- m[H##ESIZE(e)])); \
+ mul =3D (LTYPE)n[H4(e + 1 * XCHG)] * m[H4(e)]; \
} \
- acc =3D int128_add(acc, int128_make64(1 << 7)); \
+ mul =3D (mul >> 8) + ((mul >> 7) & 1); \
+ a +=3D mul; \
} \
} \
mve_advance_vpt(env); \
- return int128_getlo(int128_rshift(acc, 8)); \
+ return a; \
}
=20
-DO_LDAVH(vrmlaldavhsw, 4, int32_t, false, int128_add, int128_add, int128_m=
akes64)
-DO_LDAVH(vrmlaldavhxsw, 4, int32_t, true, int128_add, int128_add, int128_m=
akes64)
+DO_LDAVH(vrmlaldavhsw, int32_t, int64_t, false, false)
+DO_LDAVH(vrmlaldavhxsw, int32_t, int64_t, true, false)
=20
-DO_LDAVH(vrmlaldavhuw, 4, uint32_t, false, int128_add, int128_add, int128_=
make64)
+DO_LDAVH(vrmlaldavhuw, uint32_t, uint64_t, false, false)
=20
-DO_LDAVH(vrmlsldavhsw, 4, int32_t, false, int128_add, int128_sub, int128_m=
akes64)
-DO_LDAVH(vrmlsldavhxsw, 4, int32_t, true, int128_add, int128_sub, int128_m=
akes64)
+DO_LDAVH(vrmlsldavhsw, int32_t, int64_t, false, true)
+DO_LDAVH(vrmlsldavhxsw, int32_t, int64_t, true, true)
=20
/* Vector add across vector */
#define DO_VADDV(OP, ESIZE, TYPE) \
--=20
2.20.1