Path: csiph.com!eternal-september.org!feeder.eternal-september.org!nntp.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: Microcontroller software stacks (was Re: this girl calls c ugly) Date: Sun, 21 Jun 2026 14:13:23 -0700 Organization: A noiseless patient Spider Lines: 39 Message-ID: <86h5mv8umk.fsf@linuxsc.com> References: <10v7b32$2u85v$1@dont-email.me> <10vjsg2$259m3$3@dont-email.me> <10vkk65$l8v$1@reader1.panix.com> <10vlvie$2ne3j$2@dont-email.me> <10vmh2e$b44$1@reader1.panix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Sun, 21 Jun 2026 21:13:24 +0000 (UTC) Injection-Info: dont-email.me; logging-data="1130726"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19p2WQnjnYozL4J/Y6R6oeS4WOVUg1Ysyg="; posting-host="2b3d50cfcc30094bddf35dd8855beef6" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:LzSntiPveHmRekJ6nsvKBquBlOM= sha1:DmkR2+rExV/krdP442N3hOqEs1w= sha256:QiT/mZj+JbALa3ldaYUoAQyaBcVBGsBhwYpAJgDzz+A= sha1:clRMwa2DVHrrn3/KIwfNwNIXOds= Xref: csiph.com comp.lang.c:400174 scott@slp53.sl.home (Scott Lurndal) writes: > One might also define data structures for control and status > registers using bitfield structs. Yeah. This kind of application (among others) I consider one of the motivating forces behind bitfields. [Some whitespace trimming done in the excerpt below.] > e.g. for the SATA UAHC_GLB_OOBR register: > > union UAHC_GBL_OOBR { > uint32_t u; > struct UAHC_GBL_OOBR_s { > #if __BYTE_ORDER == __BIG_ENDIAN > uint32_t we : 1; /**< R/W/H - Write enable. */ > uint32_t cwmin : 7; /**< R/W/H - COMWAKE minimum value [...] */ > uint32_t cwmax : 8; /**< R/W/H - COMWAKE maximum value [...] */ > uint32_t cimin : 8; /**< R/W/H - COMINIT minimum value [...] */ > uint32_t cimax : 8; /**< R/W/H - COMINIT maximum value [...] */ > #else > uint32_t cimax : 8; > uint32_t cimin : 8; > uint32_t cwmax : 8; > uint32_t cwmin : 7; > uint32_t we : 1; > #endif > } s; > }; To me it seems kind of goofy to use uint32_t for the bitfields type. I would just use unsigned, which is just as sure to work as intended, isn't it? (Personal note: I tried sending an email to you at the address in your news posting, but my mailer complained about the address. If it's okay could I ask you to send me an email at the address in my news posting? Whatever you decide, thanks.)