From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matan Azrad Subject: Re: [PATCH v3 1/2] eal: add API to align integer to previous power of 2 Date: Wed, 4 Apr 2018 17:11:22 +0000 Message-ID: References: <20180217104934.17291-1-pbhagavatula@caviumnetworks.com> <20180404101606.5156-1-pbhagavatula@caviumnetworks.com> <20180404164207.GA21153@ltp-pvn> 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 EUR03-DB5-obe.outbound.protection.outlook.com (mail-eopbgr40065.outbound.protection.outlook.com [40.107.4.65]) by dpdk.org (Postfix) with ESMTP id 360E71C81E for ; Wed, 4 Apr 2018 19:11:30 +0200 (CEST) In-Reply-To: <20180404164207.GA21153@ltp-pvn> 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" From: Pavan Nikhilesh, Wednesday, April 4, 2018 7:42 PM > Hi Matan, >=20 > On Wed, Apr 04, 2018 at 04:10:36PM +0000, Matan Azrad wrote: > > Hi Pavan > > > > Shouldn't the new APIs be tagged with the experimental tag as agreed? >=20 > Can't tag it experimental as it causes cyclic dependency (need to include > rte_compact.h). You probably mean rte_compat.h. It is ok to add it, what is the issue with that? > Besides it's a simple proven math API I don't think it will change anytim= e > soon. It has already discussed: https://dpdk.org/dev/patchwork/patch/35211/ I think you need to add it anyway. > Thanks, > Pavan >=20 > > > > Besides that, > > Acked-by: Matan Azrad > > > > From: Pavan Nikhilesh, Wednesday, April 4, 2018 1:16 PM > > > Add 32b and 64b API's to align the given integer to the previous powe= r of > 2. > > > > > > Signed-off-by: Pavan Nikhilesh > > > --- > > > v3 Changes: > > > - Move commonly used code to rte_combine(32/64)ms1b so that it can > > > be reused. > > > > > > 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 = power of > 2. > > > > > > lib/librte_eal/common/include/rte_common.h | 92 > > > ++++++++++++++++++++++++++---- > > > 1 file changed, 81 insertions(+), 11 deletions(-) > > > > > > diff --git a/lib/librte_eal/common/include/rte_common.h > > > b/lib/librte_eal/common/include/rte_common.h > > > index c7803e41c..7e147dcf2 100644 > > > --- a/lib/librte_eal/common/include/rte_common.h > > > +++ b/lib/librte_eal/common/include/rte_common.h > > > @@ -223,6 +223,51 @@ extern int > RTE_BUILD_BUG_ON_detected_error; } > > > while(0) #endif > > > > > > +/** > > > + * Combines 32b inputs most significant set bits into the least > > > + * significant bits to construct a value with the same MSBs as x > > > + * but all 1's under it. > > > + * > > > + * @param x > > > + * The integer whose MSBs need to be combined with its LSBs > > > + * @return > > > + * The combined value. > > > + */ > > > +static inline uint32_t > > > +rte_combine32ms1b(register 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; > > > +} > > > + > > > +/** > > > + * Combines 64b inputs most significant set bits into the least > > > + * significant bits to construct a value with the same MSBs as x > > > + * but all 1's under it. > > > + * > > > + * @param v > > > + * The integer whose MSBs need to be combined with its LSBs > > > + * @return > > > + * The combined value. > > > + */ > > > +static inline uint64_t > > > +rte_combine64ms1b(register 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; > > > +} > > > + > > > /*********** Macros to work with powers of 2 ********/ > > > > > > /** > > > @@ -250,15 +295,28 @@ static inline uint32_t rte_align32pow2(uint32_= t > x) { > > > x--; > > > - x |=3D x >> 1; > > > - x |=3D x >> 2; > > > - x |=3D x >> 4; > > > - x |=3D x >> 8; > > > - x |=3D x >> 16; > > > + x =3D rte_combine32ms1b(x); > > > > > > return x + 1; > > > } > > > > > > +/** > > > + * 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 rte_combine32ms1b(x); > > > + > > > + return x - (x >> 1); > > > +} > > > + > > > /** > > > * Aligns 64b input parameter to the next power of 2 > > > * > > > @@ -272,16 +330,28 @@ static inline uint64_t rte_align64pow2(uint64_= t > v) { > > > 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; > > > + v =3D rte_combine64ms1b(v); > > > > > > return v + 1; > > > } > > > > > > +/** > > > + * 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 rte_combine64ms1b(v); > > > + > > > + return v - (v >> 1); > > > +} > > > + > > > /*********** Macros for calculating min and max **********/ > > > > > > /** > > > -- > > > 2.16.3 > >