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Groups > comp.arch.embedded > #29638
| From | Stefan Reuther <stefan.news@arcor.de> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Making more of the C standard library mandatory for freestanding implementations |
| Date | 2020-05-08 17:33 +0200 |
| Message-ID | <r94561.46o.1@stefan.msgid.phost.de> (permalink) |
| References | (1 earlier) <r8upn1$89t$1@reader2.panix.com> <r8urd0$7el$1@solani.org> <r8uuj1$3j8$1@reader2.panix.com> <r91ibh.48o.1@stefan.msgid.phost.de> <r91fqu$kk0$1@reader2.panix.com> |
Am 07.05.2020 um 19:17 schrieb Grant Edwards: > On 2020-05-07, Stefan Reuther <stefan.news@arcor.de> wrote: >> I'm actually pretty surprised that memcpy is NOT required part of a >> freestanding implementation (hadn't looked for a while...) because >> compilers actually call memcpy even if the programmer does not call >> it, for structure assignment. >> >> https://gcc.godbolt.org/z/wGNKDZ > > Yea, that's an acknowleged and documented "feature" of GCC: > > https://gcc.gnu.org/onlinedocs/gcc/Standards.html > > See the penultimate paragraph in section 2.1. I get similar code from ARM msvc, x86-64 clang, and armv8-a clang, so gcc is not an outlier here. >> In addition to that, compilers call a bunch of other little helper >> functions (e.g. long long division), so they will have a way to pull >> functions out of a library if needed. > > I don't think anybody claimed that there are no low-level compiler > support library functions required when linking in "freestanding" > mode. Those are typically reserved for use by the compiler and not > visible to the user. The point I tried to make is that there's little reason to worry that there is a compiler that links in all of libc if memcpy is used, because compilers have a means of linking these functions as needed. TL;DR: I don't see any technical roadblocks that would prevent requiring more utility functions for a freestanding implementation. Stefan
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Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-06 18:19 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-06 16:47 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-06 19:16 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-06 18:10 +0000
Re: Making more of the C standard library mandatory for freestanding implementations James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-05-06 15:10 -0400
Re: Making more of the C standard library mandatory for freestanding implementations Richard Damon <Richard@Damon-Family.org> - 2020-05-06 16:08 -0400
Re: Making more of the C standard library mandatory for freestanding implementations Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-05-06 13:22 -0700
Re: Making more of the C standard library mandatory for freestanding implementations Richard Damon <Richard@Damon-Family.org> - 2020-05-06 22:29 -0400
Re: Making more of the C standard library mandatory for freestanding implementations David Brown <david.brown@hesbynett.no> - 2020-05-07 15:43 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-06 22:36 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-06 20:57 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2020-05-06 23:25 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-06 21:34 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-07 10:17 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-05-07 18:45 +0300
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-07 10:16 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2020-05-07 21:39 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-07 21:44 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Paul Rubin <no.email@nospam.invalid> - 2020-05-07 12:54 -0700
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-06 22:34 +0200
Re: Making more of the C standard library mandatory for freestanding implementations upsidedown@downunder.com - 2020-05-07 09:13 +0300
Re: Making more of the C standard library mandatory for freestanding implementations Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-05-07 18:47 +0300
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-07 15:51 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-05-08 10:09 +0300
Re: Making more of the C standard library mandatory for freestanding implementations Stefan Reuther <stefan.news@arcor.de> - 2020-05-07 18:00 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-07 17:17 +0000
Re: Making more of the C standard library mandatory for freestanding implementations David Brown <david.brown@hesbynett.no> - 2020-05-07 20:23 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Stefan Reuther <stefan.news@arcor.de> - 2020-05-08 17:33 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-08 15:56 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-08 20:31 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-08 18:53 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-08 21:32 +0200
Re: Making more of the C standard library mandatory for freestanding implementations David Brown <david.brown@hesbynett.no> - 2020-05-09 00:13 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Richard Damon <Richard@Damon-Family.org> - 2020-05-08 18:45 -0400
Re: Making more of the C standard library mandatory for freestanding implementations Grant Edwards <invalid@invalid.invalid> - 2020-05-08 22:59 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Richard Damon <Richard@Damon-Family.org> - 2020-05-09 08:29 -0400
Re: Making more of the C standard library mandatory for freestanding implementations David Brown <david.brown@hesbynett.no> - 2020-05-09 16:10 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-05-09 20:15 +0300
Re: Making more of the C standard library mandatory for freestanding implementations David Brown <david.brown@hesbynett.no> - 2020-05-10 12:37 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Stefan Reuther <stefan.news@arcor.de> - 2020-05-09 09:52 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Florian Weimer <fw@deneb.enyo.de> - 2020-05-08 18:48 +0200
Re: Making more of the C standard library mandatory for freestanding implementations Andrew Smallshaw <andrews@sdf.org> - 2020-05-08 17:01 +0000
Re: Making more of the C standard library mandatory for freestanding implementations Philipp Klaus Krause <pkk@spth.de> - 2020-05-08 20:05 +0200
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