From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <dev-bounces@dpdk.org>
Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124])
by inbox.dpdk.org (Postfix) with ESMTP id 86388A0547;
Sat, 13 Mar 2021 02:10:10 +0100 (CET)
Received: from [217.70.189.124] (localhost [127.0.0.1])
by mails.dpdk.org (Postfix) with ESMTP id 54B48406B4;
Sat, 13 Mar 2021 02:10:10 +0100 (CET)
Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182])
by mails.dpdk.org (Postfix) with ESMTP id 6CDB04067C
for <dev@dpdk.org>; Sat, 13 Mar 2021 02:10:08 +0100 (CET)
Received: by linux.microsoft.com (Postfix, from userid 1086)
id 7E344209B364; Fri, 12 Mar 2021 17:10:07 -0800 (PST)
DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7E344209B364
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com;
s=default; t=1615597807;
bh=2/cJj4z9Hi8hzSDh4KH4969yZLqADmkQRrwqAFU+SvA=;
h=Date:From:To:Cc:Subject:References:In-Reply-To:From;
b=WfMudat308MQC5uyLmOII+gmhg8mdpZ9NvLohP6r9H8iProgPHeApIrZKforjv1+m
MwAOCDEsPmj5D8DRRYxgu1QOf6dkM9btRkplT0D4cG7QvtEGbEoWYN+zD9ghVG8wDG
K2xCszMhyTUSU8aWd2jKb9rWm0BbjXSKFk83dhsU=
Date: Fri, 12 Mar 2021 17:10:07 -0800
From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: Morten =?iso-8859-1?Q?Br=F8rup?= <mb@smartsharesystems.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>, dev@dpdk.org,
anatoly.burakov@intel.com, Ray Kinsella <mdr@ashroe.eu>,
Neil Horman <nhorman@tuxdriver.com>
Message-ID: <20210313011007.GA20712@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
References: <1615358466-12761-1-git-send-email-roretzla@linux.microsoft.com>
<20210310104942.66ef440e@hermes.local>
<20210310225238.GA10267@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
<98CBD80474FA8B44BF855DF32C47DC35C61674@smartserver.smartshare.dk>
<20210312182419.GC8084@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
<98CBD80474FA8B44BF855DF32C47DC35C6167A@smartserver.smartshare.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35C6167A@smartserver.smartshare.dk>
User-Agent: Mutt/1.5.21 (2010-09-15)
Subject: Re: [dpdk-dev] [PATCH] librte_eal/common: fix return type of
rte_bsf64
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
<mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
<mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>
On Fri, Mar 12, 2021 at 10:13:30PM +0100, Morten Brørup wrote:
> > >
> > > Please also update the similar math functions in rte_common.h, so the
> > return type is consistent across these functions:
> > > - rte_bsf32()
> > > - rte_bsf32_safe()
> > > - rte_fls_u32()
> > > - rte_bsf64()
> > > - rte_fls_u64()
> > > - rte_log2_u32()
> > > - rte_log2_u64()
> >
> > agreed, happy to review the whole set and deal with it all at once.
>
> Ups. I should have omitted rte_bsf32_safe() from the list. It returns a Boolean.
if we can agree that we can use C11 as a base we could just do away with
all this dumb 32-bit vs 64-bit static selection at the call site (at
least for rte_bsf32() and rte_bsf64() and probably others).
i could just introduce the following macro and deprecate the current
inline functions.
#define rte_bsf(v) \
(uint32_t)_Generic((v), \
uint8_t: __builtin_ctz, \
uint16_t: __builtin_ctz, \
uint32_t: __builtin_ctz, \
default: __builtin_ctzll)(v)
uint8_t a = ...;
uint16_t b = ...;
uint32_t c = ...;
uint64_t d = ...;
the following would jw as intended, though given the range of the value
that may be returned we could narrow the cast to uint8_t so we don't
have to sprinkle casts in places where usage like uint8_t x = rte_bsf(v);
exists.
rte_bsf(a);
rte_bsf(b);
rte_bsf(c);
rte_bsf(d);
anyway, if people care let me know otherwise i'm just going to review
and fix what is already there.