From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matan Azrad Subject: Re: [PATCH v2 1/2] eal: add API to align integer to previous power of 2 Date: Mon, 19 Feb 2018 12:09:46 +0000 Message-ID: References: <20180217104934.17291-1-pbhagavatula@caviumnetworks.com> <20180219113643.10337-1-pbhagavatula@caviumnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "dev@dpdk.org" To: Pavan Nikhilesh , "jerin.jacob@caviumnetworks.com" , "keith.wiles@intel.com" , Thomas Monjalon Return-path: Received: from EUR02-HE1-obe.outbound.protection.outlook.com (mail-eopbgr10074.outbound.protection.outlook.com [40.107.1.74]) by dpdk.org (Postfix) with ESMTP id 53C6B7CEF for ; Mon, 19 Feb 2018 13:09:48 +0100 (CET) In-Reply-To: <20180219113643.10337-1-pbhagavatula@caviumnetworks.com> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi Pavan > From: Pavan Nikhilesh, Monday, February 19, 2018 1:37 PM > Add 32b and 64b API's to align the given integer to the previous power of= 2. >=20 > Signed-off-by: Pavan Nikhilesh > --- > v2 Changes: > - Modified api name to `rte_align(32/64)prevpow2` from > `rte_align(32/64)lowpow2`. > - corrected fuction to return if the integer is already aligned to powe= r of 2. >=20 > lib/librte_eal/common/include/rte_common.h | 43 > ++++++++++++++++++++++++++++++ > 1 file changed, 43 insertions(+) >=20 > diff --git a/lib/librte_eal/common/include/rte_common.h > b/lib/librte_eal/common/include/rte_common.h > index c7803e41c..b2017ee5c 100644 > --- a/lib/librte_eal/common/include/rte_common.h > +++ b/lib/librte_eal/common/include/rte_common.h > @@ -259,6 +259,27 @@ rte_align32pow2(uint32_t x) > return x + 1; > } >=20 > +/** > + * Aligns input parameter to the previous power of 2 > + * > + * @param x > + * The integer value to algin > + * > + * @return > + * Input parameter aligned to the previous power of 2 > + */ > +static inline uint32_t > +rte_align32prevpow2(uint32_t x) > +{ > + x |=3D x >> 1; > + x |=3D x >> 2; > + x |=3D x >> 4; > + x |=3D x >> 8; > + x |=3D x >> 16; > + > + return x - (x >> 1); > +} Nice. Since you are using the same 5 lines from the rte_align32pow2() function, I= think this part can be in a separate function to do reuse. Also the "fill ones 32" function can be used for other purpose. What do you think? =20 > /** > * Aligns 64b input parameter to the next power of 2 > * > @@ -282,6 +303,28 @@ rte_align64pow2(uint64_t v) > return v + 1; > } >=20 > +/** > + * Aligns 64b input parameter to the previous power of 2 > + * > + * @param v > + * The 64b value to align > + * > + * @return > + * Input parameter aligned to the previous power of 2 > + */ > +static inline uint64_t > +rte_align64prevpow2(uint64_t v) > +{ > + v |=3D v >> 1; > + v |=3D v >> 2; > + v |=3D v >> 4; > + v |=3D v >> 8; > + v |=3D v >> 16; > + v |=3D v >> 32; > + > + return v - (v >> 1); > +} > + > /*********** Macros for calculating min and max **********/ >=20 > /** > -- > 2.16.1