From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 30 Jul 2024 13:11:22 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1sYklG-004RZr-2u for lore@lore.pengutronix.de; Tue, 30 Jul 2024 13:11:22 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1sYklG-00044L-9b for lore@pengutronix.de; Tue, 30 Jul 2024 13:11:22 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RF4dwRXopTNSXKT1nszVf4DARG6Ioq2DjHhStGz5JrQ=; b=QogSzb3wEgMHfRhT9fIe06Bs9e Bs+zYfKfqxsaIVN0IRcJIohaYLf8BIfY6h8rs18KLzpM2VFTYGqyB7UECPLfXNwZR+CUuupoxyXlI 67rO8xy5W2jVLGm0u2h4pg1u1J57MAS976UCNlW134ARaibcLmVkQvsS4b5VQ+94A6qLWYLHEjKsu tKymmV2tS1mxtZayqd295wSpDMqA506ZAcmSiAkRctSNKO+uIB0e9Y44b9J2rSCsbM7O4ipUxk2Tt /90XdD5AfmYhmW5aCFASj1NIKIPzJ+raNPkH1+ggMSuQqPbG+oq21hVw0rtod6+Fm6qQ5Ly9KTeNc nFtdIBqw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sYkkp-0000000Eqkr-2CpL; Tue, 30 Jul 2024 11:10:55 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sYkkl-0000000EqjF-42lJ for barebox@lists.infradead.org; Tue, 30 Jul 2024 11:10:53 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1sYkkk-00041O-MT; Tue, 30 Jul 2024 13:10:50 +0200 Message-ID: <7f41a2ea-e6da-45a0-9df6-550df630794d@pengutronix.de> Date: Tue, 30 Jul 2024 13:10:50 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Sascha Hauer Cc: barebox@lists.infradead.org References: <20240730071929.2016537-1-a.fatoum@pengutronix.de> <20240730071929.2016537-5-a.fatoum@pengutronix.de> Content-Language: en-US From: Ahmad Fatoum In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240730_041052_037524_CE90095D X-CRM114-Status: GOOD ( 19.70 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.3 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 04/10] mci: turn bool members into bitfield in struct mci X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) On 30.07.24 11:06, Sascha Hauer wrote: > On Tue, Jul 30, 2024 at 09:19:23AM +0200, Ahmad Fatoum wrote: >> In preparation for adding more boolean flags, turn the current two bools >> into two bits sharing the same u8-sized member. >> >> Signed-off-by: Ahmad Fatoum >> --- >> include/mci.h | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/include/mci.h b/include/mci.h >> index 773aed896c96..4f1ff9dc57c8 100644 >> --- a/include/mci.h >> +++ b/include/mci.h >> @@ -568,8 +568,8 @@ struct mci { >> unsigned csd[4]; /**< card's "card specific data register" */ >> unsigned cid[4]; /**< card's "card identification register" */ >> unsigned short rca; /**< relative card address */ >> - bool sdio; /**< card is a SDIO card */ >> - bool high_capacity; /**< high capacity card is connected (OCR -> OCR_HCS) */ >> + u8 sdio:1; /**< card is a SDIO card */ >> + u8 high_capacity:1; /**< high capacity card is connected (OCR -> OCR_HCS) */ > > This doesn't seem to be necessary. They share the same byte in either > way. From a quick test: They don't share the same byte, but the size didn't change because of padding. More members are added into the padding space in subsequent commits, which would affect structure size. > > struct foo { > u16 a; > bool b; > bool c; > u32 d; > }; > > struct bar { > u16 a; > u8 b:1; > u8 c:1; > u32 d; > }; > > printf("%d %d\n", sizeof(struct foo), sizeof(struct bar)); > > The result is 8 for both structs. > > Sascha > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |