Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Keith Thompson Newsgroups: comp.lang.c Subject: Re: va_start without the first argument? Date: Sat, 11 Mar 2017 11:56:41 -0800 Organization: None to speak of Lines: 30 Message-ID: References: <6efb4ec5-8a50-4ecd-95ac-3328682a7a03@googlegroups.com> <1c6010ab-c0e6-468b-8b9d-94cbe2aa4ac8@googlegroups.com> <3fb4148c-8b5b-468c-8399-e5a5fc8575ee@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: mx02.eternal-september.org; posting-host="624f8955d1629b31024313bb1680f18f"; logging-data="7526"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/dDIsYlIGgsJMIrMm+VNXe" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) Cancel-Lock: sha1:+LrVuKsRlOvbAHGJfsmB4gwr6W8= sha1:UV287C7BQc9oifNAZbrdMe71a8o= Xref: csiph.com comp.lang.c:105813 BartC writes: > On 11/03/2017 18:53, jacobnavia wrote: [...] >> Gcc followed the much more complicated but more efficient route of >> making 3 different heaps of arguments: >> >> 1) Arguments passed in integer registers. >> 2) Arguments passed in floating point registers. >> 3) Arguments passed in RAM (stack). >> >> Pointers and integers up to register size go into (1). All floating >> point goes into heap > > The heap? No. > (2) (the xmm registers) and in (3) we find all >> arguments that come after any of the first two is exhausted. jacob isn't using the word "heap" in its technical sense. I think "group" would have been clearer. What he said was that "All floating point goes into heap (2)", i.e., the group of arguments that are passed in FP registers. -- Keith Thompson (The_Other_Keith) kst-u@mib.org Working, but not speaking, for JetHead Development, Inc. "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister"