From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 4F94443B76; Tue, 5 Mar 2024 19:22:24 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id D57A440271; Tue, 5 Mar 2024 19:22:23 +0100 (CET) Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by mails.dpdk.org (Postfix) with ESMTP id B295940270 for ; Tue, 5 Mar 2024 19:22:22 +0100 (CET) Received: by linux.microsoft.com (Postfix, from userid 1086) id D3ABA20B74C0; Tue, 5 Mar 2024 10:22:21 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D3ABA20B74C0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1709662941; bh=vF5nkaIORGNFa1geFzMyG4TuD5cRwp6JhjBJvSm4hT4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oTppvBf4QhcRapDEi2XOTpyernuN2iyPZaw0GVB6AUGOypfGkGQSs1uZAgPcEKg2n mc6ihZQoThpNHUaOUAj/Yc2g8S9bj/mvkl+v4MwMbydszHbMPvOeaD226dLAAscjtu hwxGS9Wvd5dwYSKGnBF/bbgUDyTGjRXbFpk3+7Ow= Date: Tue, 5 Mar 2024 10:22:21 -0800 From: Tyler Retzlaff To: Mattias =?iso-8859-1?Q?R=F6nnblom?= Cc: Mattias =?iso-8859-1?Q?R=F6nnblom?= , dev@dpdk.org, Heng Wang Subject: Re: [RFC 2/7] eal: add generic bit manipulation macros Message-ID: <20240305182221.GA24679@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> References: <20240302135328.531940-1-mattias.ronnblom@ericsson.com> <20240302135328.531940-3-mattias.ronnblom@ericsson.com> <20240304164224.GB16065@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> <5c43fd54-6e59-4882-9efa-f3b3dff98b11@lysator.liu.se> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5c43fd54-6e59-4882-9efa-f3b3dff98b11@lysator.liu.se> User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Tue, Mar 05, 2024 at 07:08:36PM +0100, Mattias Rönnblom wrote: > On 2024-03-04 17:42, Tyler Retzlaff wrote: > >On Sat, Mar 02, 2024 at 02:53:23PM +0100, Mattias Rönnblom wrote: > >>Add bit-level test/set/clear/assign macros operating on both 32-bit > >>and 64-bit words by means of C11 generic selection. > >> > >>Signed-off-by: Mattias Rönnblom > >>--- > > > >_Generic is nice here. should we discourage direct use of the inline > >functions in preference of using the macro always? either way lgtm. > > > > That was something I considered, but decided against it for RFC v1. > I wasn't even sure people would like _Generic. > > The big upside of having only the _Generic macros would be a much > smaller API, but maybe a tiny bit less (type-)safe to use. i'm curious what misuse pattern you anticipate or have seen that may be less type-safe? just so i can look out for them. i (perhaps naively) have liked generic functions for their selection of the "correct" type and for _Generic if no leg/case exists compiler error (as opposed to e.g. silent truncation). > > Also, _Generic is new for DPDK, so who knows what issues it might > cause with old compilers. i was thinking about this overnight, it's supposed to be standard C11 and my use on various compilers showed no problem but I can't recall if i did any evaluation when consuming as a part of a C++ translation unit so there could be problems. > > Thanks. > > >Acked-by: Tyler Retzlaff > > > >> lib/eal/include/rte_bitops.h | 81 ++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 81 insertions(+) > >> > >>diff --git a/lib/eal/include/rte_bitops.h b/lib/eal/include/rte_bitops.h > >>index 9a368724d5..afd0f11033 100644 > >>--- a/lib/eal/include/rte_bitops.h > >>+++ b/lib/eal/include/rte_bitops.h > >>@@ -107,6 +107,87 @@ extern "C" { > >> #define RTE_FIELD_GET64(mask, reg) \ > >> ((typeof(mask))(((reg) & (mask)) >> rte_ctz64(mask))) > >>+/** > >>+ * Test bit in word. > >>+ * > >>+ * Generic selection macro to test the value of a bit in a 32-bit or > >>+ * 64-bit word. The type of operation depends on the type of the @c > >>+ * addr parameter. > >>+ * > >>+ * This macro does not give any guarantees in regards to memory > >>+ * ordering or atomicity. > >>+ * > >>+ * @param addr > >>+ * A pointer to the word to modify. > >>+ * @param nr > >>+ * The index of the bit. > >>+ */ > >>+#define rte_bit_test(addr, nr) \ > >>+ _Generic((addr), \ > >>+ uint32_t *: rte_bit_test32, \ > >>+ uint64_t *: rte_bit_test64)(addr, nr) > >>+ > >>+/** > >>+ * Set bit in word. > >>+ * > >>+ * Generic selection macro to set a bit in a 32-bit or 64-bit > >>+ * word. The type of operation depends on the type of the @c addr > >>+ * parameter. > >>+ * > >>+ * This macro does not give any guarantees in regards to memory > >>+ * ordering or atomicity. > >>+ * > >>+ * @param addr > >>+ * A pointer to the word to modify. > >>+ * @param nr > >>+ * The index of the bit. > >>+ */ > >>+#define rte_bit_set(addr, nr) \ > >>+ _Generic((addr), \ > >>+ uint32_t *: rte_bit_set32, \ > >>+ uint64_t *: rte_bit_set64)(addr, nr) > >>+ > >>+/** > >>+ * Clear bit in word. > >>+ * > >>+ * Generic selection macro to clear a bit in a 32-bit or 64-bit > >>+ * word. The type of operation depends on the type of the @c addr > >>+ * parameter. > >>+ * > >>+ * This macro does not give any guarantees in regards to memory > >>+ * ordering or atomicity. > >>+ * > >>+ * @param addr > >>+ * A pointer to the word to modify. > >>+ * @param nr > >>+ * The index of the bit. > >>+ */ > >>+#define rte_bit_clear(addr, nr) \ > >>+ _Generic((addr), \ > >>+ uint32_t *: rte_bit_clear32, \ > >>+ uint64_t *: rte_bit_clear64)(addr, nr) > >>+ > >>+/** > >>+ * Assign a value to a bit in word. > >>+ * > >>+ * Generic selection macro to assign a value to a bit in a 32-bit or 64-bit > >>+ * word. The type of operation depends on the type of the @c addr parameter. > >>+ * > >>+ * This macro does not give any guarantees in regards to memory > >>+ * ordering or atomicity. > >>+ * > >>+ * @param addr > >>+ * A pointer to the word to modify. > >>+ * @param nr > >>+ * The index of the bit. > >>+ * @param value > >>+ * The new value of the bit - true for '1', or false for '0'. > >>+ */ > >>+#define rte_bit_assign(addr, nr, value) \ > >>+ _Generic((addr), \ > >>+ uint32_t *: rte_bit_assign32, \ > >>+ uint64_t *: rte_bit_assign64)(addr, nr, value) > >>+ > >> /** > >> * Test if a particular bit in a 32-bit word is set. > >> * > >>-- > >>2.34.1